# Unit 1 Chemical Changes and Structure Revision Notes

Size: px
Start display at page:

Transcription

1 Unit 1 Revision Notes Rates of reaction The rate of reaction can be increased by: increasing the concentration of a solution decreasing the particle size of a solid increasing the temperature adding a catalyst. The average rate of reaction can be calculated from a graph of the change in mass or volume against time. Measuring a change in mass g Time (s) Average rate of reaction = change in mass change in time Average rate over first 10 s = Average rate between 10 s and 20 s = = 0.40 = = 0.04 gs -1 = 0.02 gs -1 Average rate over first 20 s = Average rate between 10 s and 50 s = = 0.60 = = 0.03 gs -1 = gs -1 1

2 Measuring a change in volume Average rate of reaction = change in volume change in time Average rate of reaction = 65 0 = = 0.76 cm 3 s -1 Interpreting a graph that follows the course of a reaction. Gradient (or steepness) of line indicates rate (the steeper the line the faster the rate). The end of the reaction is marked by the line levelling out, quantity of product (or reactant) no longer changing. Total volume of gas produced in eample above = 65 cm 3 Note: Always give a positive value for rate. Units for rate (from a graph) = unit for y-ais followed by unit for -ais -1 or (from a table) = unit for recorded variable (dependent variable) followed by unit for time -1 In the eamples shown above the rate of reaction decreases as the reaction progresses, this is due to a reduction in the concentration of the reactants as the reaction proceeds. Note: if the gas being collected is insoluble in water then the apparatus in the diagram shown below can be used to show the change in volume with time. 2

3 Atomic structure and bonding related to properties of materials Atomic structure Atoms contain three types of subatomic particles. e.g. a lithium atom nucleus 1 st energy level (can hold a maimum of 2 electrons). 2 nd energy level (can hold a maimum of 8 electrons). Electron arrangement = 2,1 electron proton neutron Particle Mass Charge neutron 1 amu neutral proton 1 amu positive electron almost zero negative Atoms are neutral number of protons = number of electrons Nuclide notation mass number atomic number 7 3 Li mass number = number of protons + number of neutrons atomic number = number of protons Isotopes - atoms with the same number of protons but a different number of neutrons - atoms with the same atomic number but a different mass number e.g. isotopes of chlorine % 17 25% Relative atomic mass the average mass of the isotopes present taking into account their relative proportions. e.g. relative atomic mass of chlorine = (35 75) + (37 25) 100 = = = 35.5 amu Note: the relative atomic mass (RAM) of an element is closer to the mass of the most abundant isotope. owever, RAM for Br = 80 amu 79 Br 50% and 81 Br 50% 3

4 4

5 Notes on Elements and the Periodic Table Elements are arranged in order of increasing atomic number. It is the electron arrangement of an atom that determines its chemical properties. Isotopes have identical chemical properties because they have the same electron arrangement. Atoms of elements in the same group have the same number of electrons in their outer energy levels and as a result have similar chemical properties. The elements in Group 0 (the Noble gases) are the most stable elements in the Periodic Table. The Noble gases have full outer energy levels. The diatomic elements are ydrogen (2), Nitrogen (N2), ygen (2), Fluorine (F2), Chlorine (2), Bromine (Br2) and Iodine (I2) NF and down. An atom (or ion) with a full outer energy level is more stable than one which does not have a full outer energy level. Covalent bonding Atoms can achieve a stable electron arrangement by sharing outer electrons forming a covalent bond. e.g. hydrogen, 2 The shared pair of electrons is attracted to the nuclei of the two bonded atoms. Both ydrogen atoms now have an electron arrangement of 2 (a full outer energy level like elium). More than one bond can be formed between atoms leading to double and triple covalent bonds. Dot and cross diagram Electron cloud diagram Structural formula ygen, 2 ygen, 2 ygen, 2 X X X X X X X X X X X X Nitrogen, N2 Nitrogen, N2 Nitrogen, N2 X X N X X X N X X N X N X N N 5

6 Covalent substances can form either discrete molecular or giant network structures. Covalent molecular Diagrams show how outer electrons are shared to form the covalent bond(s) in a molecule and the shape of simple two-element compounds. Dot and cross diagram Electron cloud diagram Shape Structural formula ydrogen fluoride F F F F linear Molecular formula: F Carbon dioide C C C C linear Molecular formula: C2 Water bent Molecular formula: 2 6

7 Sulphur dichloride Ammonia Phosphorus trichloride Dot and cross diagram Electron cloud diagram Shape Structural formula S N S N bent N S trigonal pyramidal Molecular formula: S2 Molecular formula: N3 S N P P P P trigonal pyramidal Molecular formula: P3 7

8 Methane Dot and cross diagram Electron cloud diagram Shape Structural formula C C C tetrahedral C Molecular formula: C4 Tetrachloromethane P C C tetrahedral C Molecular formula: C4 8

9 Bonding in covalent substances and the related trend in melting points Covalent molecular e.g. carbon dioide weak forces of attraction Covalent molecular substances have low melting points due to only weak forces of strong covalent bonds attraction between molecules being broken. Covalent network e.g. diamond strong covalent bonds Covalent network structures have very high melting points because the network of strong covalent bonds must be broken. Ions Atoms can achieve a stable electron arrangement by losing or gaining electrons and forming ions. e.g. a sodium atom, Na, with an electron arrangement of 2,8,1 can lose an electron to become a sodium ion,, with more stable electron arrangement of 2,8. Key - nucleus + - energy level - electron Na 2,8,1 2,8 This reaction can be shown as an ion-electron equation: Na + e - and a chlorine atom,, with an electron arrangement of 2,8,7 can gain an electron to become a chloride ion, -, with more stable electron arrangement of 2,8,8. + 2,8,7-2,8,8 This reaction can be shown as an ion-electron equation: + e - - The charge on an ion of an element in group 1 to 0 can be determined using the pattern in the table below. Group Charge on ion not applicable not applicable Note: The charge on transition metal ions can vary and is given as roman numerals in the name, e.g. in copper(ii) chloride the copper ion has a 2+ charge, Cu 2+. 9

10 Nuclide notation for ions mass number atomic number Ca 2+ charge on ion There is an imbalance in the number of positive protons and negative electrons within an ion, hence the charge. Ionic compounds Ionic compounds form a lattice structure of oppositely charged ions in the solid state e.g. sodium chloride Ionic bonds are the electrostatic attraction between positive and negative ions Ionic compounds have high melting points because strong ionic bonds must be broken in order to break down the lattice. The lattice can also be broken down by being dissolved. Conduction of electricity For a substance to conduct electricity it must contain charged particles that are free to move. Covalent substances do not contain charged particles therefore do not conduct. Ionic compounds conduct electricity, only when molten or in solution due to the breakdown of the lattice resulting in the ions being free to move. Ionic compounds do not conduct electricity when solid because the ions are not free to move. They are held in a lattice. Simple eperiments to measure electrical conductivity of solids of melts of liquids including solutions A A A An ammeter A or a bulb can be used in these eperiments. EAT 10

11 Formulae and reaction quantities The formulae of most elements are given by their symbol (e.g. silicon, Si). The formulae of the diatomic elements (NF and down) are given by their symbol followed by a subscript two (e.g. bromine, Br2). Diatomic molecules are molecules which contain two atoms (e.g. hydrogen fluoride, F). The formula of a covalent molecular substance gives the number of atoms present in the molecule. The formula of a covalent network or ionic compound gives the simplest ratio of atoms or ions in the substance. Cross-valency method The formulae for substances containing two elements can be worked out using the cross-valency method. The valencies for elements in group 1-0 are given in the table below. Group Valency not applicable Formula for silicon hydride; Formula for calcium sulfide; Symbols Si Symbols Ca S Valencies 4 1 Valencies 2 2 Formula ratio 1 4 Formula ratio 2 2 Simplify ratio 1 1 Formula Si4 Formula CaS Where the compound is ionic the charges on the ions can be added e.g. Ca 2+ S 2- Formula for silicon sulfide; Formula for aluminium oide; Symbols Si S Symbols Al Valencies 4 2 Valencies 3 2 Formula ratio 2 4 Formula ratio 2 3 Simplify ratio 1 2 Formula Si2 Formula Al23 When possible, cancel down to the simplest ratio e.g. the formula for silicon sulphide is Si2 not Si24. When showing the charges a bracket is used where there is more than one of a particular ion e.g. (Al 3+ )2( 2- )3 11

12 Formulae of compounds which have prefies in their name If the name of the compound contains a prefi we do not use the cross-valency method. We use the prefi to write the formula. Prefi mono di tri tetra penta hea Number of atoms or ions e.g. silicon dioide, Si2 or dinitrogen tetroide, N24. Note: if part of the name has no prefi it is assumed that only 1 atom or ion of this type is present. Formulae of compounds containing transition metal ions The charge on transition metal ions can vary and is given as roman numerals within the name of the compound. Roman numeral I II III IV V VI Number e.g. iron(iii) oide, (Fe 3+ )2( 2- )3 Formulae of compounds with ions which contain more than one kind of atom The formulae for these ions can be found in a table on page 8 of the National 5 Chemistry Data Booklet Scottish Qualifications Authority 2013, which has been reproduced below. As we can see from all the eamples of ionic formulae given above, when writing these formulae we must ensure that the negative and positive charges balance and the compound is electrically neutral. e.g. sodium carbonate, ( )2C the sodium ion has 1 positive charge, the carbonate ion has 2 negative charges, therefore two sodium ions are needed to balance the charge on one carbonate ion. or calcium nitrate, Ca 2+ (N3 - )2 where two nitrate ions are needed to balance the charge on one calcium ion. 12

13 Chemical equations A chemical equation can be used to describe a reaction, showing the chemicals which react (reactants) and the chemicals which are produced (products). reactants products e.g. word equation sodium + water sodium hydroide + hydrogen formula equation with state symbols Na(s) + 2(l) (aq) + - (aq) + 2(g) State symbols solid (s), liquid (l), gas (g) and water based (aqueous) solution (aq). Balancing equations During a chemical reaction no atoms are lost or gained. A balanced equation shows the same number and type of atoms on each side of the equation. e.g. methane + oygen carbon dioide + water ] Number of atoms of each element Gram formula mass C C C The number of atoms of each type is not balanced. C By placing a 2 in front of the water the total number of s and s on the right hand side is altered and the hydrogen atoms are now balanced. By placing a 2 in front of the oygen the total number of s on the left hand side is altered and the equation is now balanced. The gram formula mass (GFM) of any substance can be calculated using the chemical formula and relative atomic masses of its constituent elements. Relative atomic masses of elements can be found on page 7 of the National 5 Chemistry Data Booklet. e.g. GFM of methane, C4 GFM = (1 C) + (4 ) = (1 12) + (4 1) = = 16g GFM of water, 2 GFM = (2 ) + (1 ) = (2 1) + (1 16) = = 18g Moles The gram formula mass is defined as the mass of one mole of a substance. A balanced equation gives the molar ratio of the reactants and products. e.g. C C Molar ratio: 1 mole 2 moles 1 mole 2 moles 13

14 Relationship between number of moles and mass Relationship between number of moles, volume and concentration m n n GFM v c n = number of moles m = mass, in grams, g GFM = gram formula mass, g Calculate the mass of 2.5 moles of magnesium chloride. n = number of moles v = volume, in litres, l c = concentration, in moles per litre, moll -1 Note: volumes given in cm 3 must be converted to litres (1 cm 3 = l, cm 3 = litres) 1000 Calculate the number of moles present in 200 cm 3 of a 1.5 moll -1 solution of glucose. m = n GFM = = g GFM of Mg2 = (1 Mg) + (2 ) = (1 24.5) + (2 35.5) = = 95.5g n = v c v = 200cm 3 = 200 = 0.2 l = = 0.3 moles Calculate the number of moles present in 69 g of potassium carbonate. Calculate the concentration of a 500 cm 3 solution of 5.85 g of Na. n = m GFM = = 0.5g GFM of (K + )2C3 2- = (2 K) + (1 C) + (3 ) = (2 39) + (1 12) + (3 16) = = 138g c = n v = = 0.2moll -1 n = m = 5.85 = 0.1 moles GFM 58.5 GFM of Na = (1 Na) + (1 ) = (1 23) + (1 35.5) = = 58.5g v = 500 = 0.5l 1000 Calculate the volume of 1.5 moll -1 glucose solution which would contain 0.3 moles. v = n c = = 0.2l = 200cm 3 14

15 What mass of calcium hydroide is required to produce 500 cm 3 of 0.1 moll -1 calcium hydroide solution? m = n GFM = = 3.7 g n = v c v = 500 = 0.5 l = = 0.05 moles GFM of Ca 2+ ( - )2 = (1 Ca) + (2 ) + (2 ) = (1 40) + (2 16) + (2 1) = = 74 g Calculations based on balanced equations Calculate the mass of hydrogen produced when 4 9 g of magnesium reacts with an ecess of dilute sulphuric acid. Mg(s) + 2S4(aq) MgS4(aq) + 2(g) 1 mole 1 mole 24.5 g 2 g 4.9 g = 0.4 g Rust, iron(iii) oide, that forms on cars can be treated using rust remover which contains phosphoric acid. When painted on, rust remover changes iron(iii) oide into iron(iii) phosphate. Calculate the mass of iron(iii) oide that will be removed by 250 cm 3 of 2 moll 1 phosphoric acid. Fe23(s) + 23P4(aq) 2FeP4(s) mole 2 moles v = 250 cm 3 = 0.25 l c = 2 moll -1 n = v c = = 0.5 moles moles 2 = 0.25 moles m = n gfm GFM of Fe23 = (2 Fe) + (3 ) = = (2 56) + (3 16) = 40 g = = 160 g 15

16 Acids and bases The p scale p is related to the concentration of hydrogen and hydroide ions in pure water, acids and alkalis. The relationship between p and concentration of + (aq) ions can be eplored by carrying out a dilution eperiment. The table below summaries what can be observed and calculated from one such eperiment in which repeated ten-fold dilution of a solution of 1 moll -1 hydrochloric acid was carried out. DILUTIN TWARDS p 7 Colour of Universal indicator [(aq)] in moll [ + (aq)] in moll p From the table above, we can see that there is a relationship between p and the concentration of + (aq) ions. [ + (aq)] = p The p is a measure of the hydrogen ion concentration. Water is neutral and has a p of 7. A very small proportion of water molecules will dissociate into an equal number of hydrogen and hydroide ions. In water, 2(l) + (aq) + - (aq) [ + (aq)] = [ - (aq)] = The results of a repeated ten-fold dilution of a solution of 1 moll -1 sodium hydroide solution are shown in the table below. DILUTIN TWARDS p 7 Colour of Universal indicator [Na(aq)] in moll [ - (aq)] in moll p [ + (aq)] in moll A neutral solution has an equal concentration of hydrogen and hydroide ions. A solution with a greater concentration of hydrogen ions than hydroide ions is an acid. A solution with a greater concentration of hydroide ions than hydrogen ions is an alkali. The effect of dilution of an acid or alkali with water is related to the concentrations of hydrogen and hydroide ions. 16

17 Formation of acids Acids are formed when soluble non-metal oides dissolve in water and increase the hydrogen ion concentration. e.g. sulfur dioide + water sulfurous acid S2(g) + 2(l) 2 + (aq) + S3(aq) carbon dioide + water carbonic acid C2(g) + 2(l) 2 + (aq) + C3(aq) Formation of alkalis Alkalis are formed when soluble metal-oides dissolve in water and increase hydroide ion concentration. e.g. sodium oide + water sodium hydroide ( )2 2- (s) + 2(l) 2 (aq) (aq) calcium oide + water calcium hydroide Ca (s) + 2(l) Ca 2+ (aq) (aq) Formulae of common acids and alkalis Acid Formula without charge Formula showing ions hydrochloric acid (aq) + (aq) + - (aq) nitric acid N3(aq) + (aq) + N3 - (aq) sulphuric acid 2S4(aq) 2 + (aq) + S4 2- (aq) Alkalis Formula without charge Formula showing ions lithium hydroide Li(aq) Li + (aq) + - (aq) potassium hydroide K(aq) K + (aq) + - (aq) ammonium hydroide N4(aq) N4 + (aq) + - (aq) 17

18 Neutralisation reactions A base is a substance that neutralises an acid. acid + metal oide salt + water e.g. Word equation: hydrochloric acid + sodium oide sodium chloride + water Formula equation: (aq) + Na(s) Na(aq) + 2(l) Ionic formula equation: + (aq) + - (aq) + ( )2 2- (s) (aq) + - (aq) + 2(l) Balanced ionic equation: 2 + (aq) (aq) + ( )2 2- (s) 2 (aq) (aq) + 2(l) The reacting species are determined by omission of spectator ions. 2 + (aq) (aq) + ( )2 2- (s) 2 (aq) (aq) + 2(l) acid + alkali salt + water e.g. Word equation: nitric acid + potassium hydroide potassium nitrate + water Formula equation: N3(aq) + K(aq) KN3(aq) + 2(l) Ionic formula equation: + (aq) + N3 - (aq) + K + (aq) + - (aq) K + (aq) + N3 - (aq) + 2(l) Balanced ionic equation: + (aq) + N3 - (aq) + K + (aq) + - (aq) K + (aq) + N3 - (aq) + 2(l) The reacting species are determined by omission of spectator ions. + (aq) + N3 - (aq) + K + (aq) + - (aq) K + (aq) + N3 - (aq) + 2(l) acid + metal carbonate salt + water + carbon doide e.g. Word equation: sulfuric acid + calcium carbonate calcium sulfate + water + carbon dioide Formula equation: 2S4(aq) + CaC3(s) CaS4(aq) + 2(l) + C2(g) Ionic formula equation: 2 + (aq) + S4 2- (aq) + Ca 2+ (aq) + C3 2- (aq) Ca 2+ (aq) + S4 2- (aq) + 2(l) + C2(g) Balanced ionic equation: 2 + (aq) + S4 2- (aq) + Ca 2+ (aq) + C3 2- (aq) Ca 2+ (aq) + S4 2- (aq) + 2(l) + C2(g) The reacting species are determined by omission of spectator ions. 2 + (aq) + S4 2- (aq) + Ca 2+ (aq) + C3 2- (aq) Ca 2+ (aq) + S4 2- (aq) + 2(l) + C2(g) C C2 Remember: Spectator ions are present but they don t take part in the action. These ions appear unchanged on both sides of the equation. 18

19 Naming the salt produced during neutralisation As we can see from the eamples above, the first part of the name of the salt comes from the positive ion within the base. The second part of the name of the salt is derived from the acid. Name of acid hydrochloric acid nitric acid sulfuric acid Name of salt... chloride... nitrate... sulfate Titration Titration is an analytical technique used to determine the accurate volumes involved in chemical reactions such as neutralisation. An indicator is used to show the end-point of the reaction. e.g. Rough 1st titre 2nd titre titre hydrochloric acid 0 1 moll -1 Initial burette reading/cm Final burette reading/cm 3 Volume used/cm cm 3 sodium hydroide solution + indicator Using the results in the table, calculate the concentration of the sodium hydroide solution. (aq) + Na(aq) 2(l) + Na(aq) 1 mole 1mole Average titre = v = 25.0 cm 3 v = 10 cm 3 = 25.0 cm 3 = l = l c = 0.1 moll -1 n = v c = = moles moles moles c = n = v = 0.25 moll -1 19

### Topic 4 National Chemistry Summary Notes. Formulae, Equations, Balancing Equations and The Mole

Topic 4 National Chemistry Summary Notes Formulae, Equations, Balancing Equations and The Mole LI 1 The chemical formula of a covalent molecular compound tells us the number of atoms of each element present

### Chemistry Assessment Unit AS 1

Centre Number 71 Candidate Number ADVANCED SUBSIDIARY (AS) General Certificate of Education January 2011 Chemistry Assessment Unit AS 1 assessing Basic Concepts in Physical and Inorganic Chemistry [AC111]

### WRITING CHEMICAL FORMULA

WRITING CHEMICAL FORMULA For ionic compounds, the chemical formula must be worked out. You will no longer have the list of ions in the exam (like at GCSE). Instead you must learn some and work out others.

### IB Chemistry 1 Mole. One atom of C-12 has a mass of 12 amu. One mole of C-12 has a mass of 12 g. Grams we can use more easily.

The Mole Atomic mass units and atoms are not convenient units to work with. The concept of the mole was invented. This was the number of atoms of carbon-12 that were needed to make 12 g of carbon. 1 mole

### MOLES AND MOLE CALCULATIONS

35 MOLES ND MOLE CLCULTIONS INTRODUCTION The purpose of this section is to present some methods for calculating both how much of each reactant is used in a chemical reaction, and how much of each product

### Science 20. Unit A: Chemical Change. Assignment Booklet A1

Science 20 Unit A: Chemical Change Assignment Booklet A FOR TEACHER S USE ONLY Summary Teacher s Comments Chapter Assignment Total Possible Marks 79 Your Mark Science 20 Unit A: Chemical Change Assignment

### W1 WORKSHOP ON STOICHIOMETRY

INTRODUCTION W1 WORKSHOP ON STOICHIOMETRY These notes and exercises are designed to introduce you to the basic concepts required to understand a chemical formula or equation. Relative atomic masses of

Candidate Style Answer Chemistry A Unit F321 Atoms, Bonds and Groups High banded response This Support Material booklet is designed to accompany the OCR GCE Chemistry A Specimen Paper F321 for teaching

### Chapter 6 Assessment. Name: Class: Date: ID: A. Multiple Choice Identify the choice that best completes the statement or answers the question.

Name: Class: Date: ID: A Chapter 6 Assessment Multiple Choice Identify the choice that best completes the statement or answers the question. 1. When an atom loses an electron, it forms a(n) a. anion. c.

### ATOMS. Multiple Choice Questions

Chapter 3 ATOMS AND MOLECULES Multiple Choice Questions 1. Which of the following correctly represents 360 g of water? (i) 2 moles of H 2 0 (ii) 20 moles of water (iii) 6.022 10 23 molecules of water (iv)

### The Periodic Table: Periodic trends

Unit 1 The Periodic Table: Periodic trends There are over one hundred different chemical elements. Some of these elements are familiar to you such as hydrogen, oxygen, nitrogen and carbon. Each one has

### Exam 2 Chemistry 65 Summer 2015. Score:

Name: Exam 2 Chemistry 65 Summer 2015 Score: Instructions: Clearly circle the one best answer 1. Valence electrons are electrons located A) in the outermost energy level of an atom. B) in the nucleus of

### Mole Notes.notebook. October 29, 2014

1 2 How do chemists count atoms/formula units/molecules? How do we go from the atomic scale to the scale of everyday measurements (macroscopic scale)? The gateway is the mole! But before we get to the

### Chemistry Diagnostic Questions

Chemistry Diagnostic Questions Answer these 40 multiple choice questions and then check your answers, located at the end of this document. If you correctly answered less than 25 questions, you need to

### 7.4. Using the Bohr Theory KNOW? Using the Bohr Theory to Describe Atoms and Ions

7.4 Using the Bohr Theory LEARNING TIP Models such as Figures 1 to 4, on pages 218 and 219, help you visualize scientific explanations. As you examine Figures 1 to 4, look back and forth between the diagrams

### List the 3 main types of subatomic particles and indicate the mass and electrical charge of each.

Basic Chemistry Why do we study chemistry in a biology course? All living organisms are composed of chemicals. To understand life, we must understand the structure, function, and properties of the chemicals

### Instructions Answer all questions in the spaces provided. Do all rough work in this book. Cross through any work you do not want to be marked.

GCSE CHEMISTRY Higher Tier Chemistry 1H H Specimen 2018 Time allowed: 1 hour 45 minutes Materials For this paper you must have: a ruler a calculator the periodic table (enclosed). Instructions Answer all

### TOPIC 7. CHEMICAL CALCULATIONS I - atomic and formula weights.

TOPIC 7. CHEMICAL CALCULATIONS I - atomic and formula weights. Atomic structure revisited. In Topic 2, atoms were described as ranging from the simplest atom, H, containing a single proton and usually

### B) atomic number C) both the solid and the liquid phase D) Au C) Sn, Si, C A) metal C) O, S, Se C) In D) tin D) methane D) bismuth B) Group 2 metal

1. The elements on the Periodic Table are arranged in order of increasing A) atomic mass B) atomic number C) molar mass D) oxidation number 2. Which list of elements consists of a metal, a metalloid, and

### Formulae, stoichiometry and the mole concept

3 Formulae, stoichiometry and the mole concept Content 3.1 Symbols, Formulae and Chemical equations 3.2 Concept of Relative Mass 3.3 Mole Concept and Stoichiometry Learning Outcomes Candidates should be

### Chapter 2 Atoms, Molecules, and Ions

Chapter 2 Atoms, Molecules, and Ions 1. Methane and ethane are both made up of carbon and hydrogen. In methane, there are 12.0 g of carbon for every 4.00 g of hydrogen, a ration of 3:1 by mass. In ethane,

### Name Class Date. What is ionic bonding? What happens to atoms that gain or lose electrons? What kinds of solids are formed from ionic bonds?

CHAPTER 1 2 Ionic Bonds SECTION Chemical Bonding BEFORE YOU READ After you read this section, you should be able to answer these questions: What is ionic bonding? What happens to atoms that gain or lose

### Chapter 2 The Chemical Context of Life

Chapter 2 The Chemical Context of Life Multiple-Choice Questions 1) About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living

### IB Chemistry. DP Chemistry Review

DP Chemistry Review Topic 1: Quantitative chemistry 1.1 The mole concept and Avogadro s constant Assessment statement Apply the mole concept to substances. Determine the number of particles and the amount

### Chapter 1: Moles and equations. Learning outcomes. you should be able to:

Chapter 1: Moles and equations 1 Learning outcomes you should be able to: define and use the terms: relative atomic mass, isotopic mass and formula mass based on the 12 C scale perform calculations, including

### Chapter 4: Structure and Properties of Ionic and Covalent Compounds

Chapter 4: Structure and Properties of Ionic and Covalent Compounds 4.1 Chemical Bonding o Chemical Bond - the force of attraction between any two atoms in a compound. o Interactions involving valence

### Chemistry 151 Final Exam

Chemistry 151 Final Exam Name: SSN: Exam Rules & Guidelines Show your work. No credit will be given for an answer unless your work is shown. Indicate your answer with a box or a circle. All paperwork must

### Cambridge International Examinations Cambridge International General Certificate of Secondary Education

Cambridge International Examinations Cambridge International General Certificate of Secondary Education *0123456789* CHEMISTRY 0620/03 Paper 3 Theory (Core) For Examination from 2016 SPECIMEN PAPER 1 hour

### Chemistry CA 2 Practice

hemistry 2 Practice Some questions (c) 2015 by Region 10 Educational Service enter. Some questions (c) 2015 by Progress Testing. Page 2 1 Which of the following is the mass in grams of 4.25 10³ mol of

### Atoms, Elements, and the Periodic Table (Chapter 2)

Atoms, Elements, and the Periodic Table (Chapter 2) Atomic Structure 1. Historical View - Dalton's Atomic Theory Based on empirical observations, formulated as Laws of: Conservation of Mass Definite Proportions

### Chapter 16: Tests for ions and gases

The position of hydrogen in the reactivity series Hydrogen, although not a metal, is included in the reactivity series because it, like metals, can be displaced from aqueous solution, only this time the

### Untitled Document. 1. Which of the following best describes an atom? 4. Which statement best describes the density of an atom s nucleus?

Name: Date: 1. Which of the following best describes an atom? A. protons and electrons grouped together in a random pattern B. protons and electrons grouped together in an alternating pattern C. a core

### In the box below, draw the Lewis electron-dot structure for the compound formed from magnesium and oxygen. [Include any charges or partial charges.

Name: 1) Which molecule is nonpolar and has a symmetrical shape? A) NH3 B) H2O C) HCl D) CH4 7222-1 - Page 1 2) When ammonium chloride crystals are dissolved in water, the temperature of the water decreases.

### Lewis Dot Structures of Atoms and Ions

Why? The chemical properties of an element are based on the number of electrons in the outer shell of its atoms. We use Lewis dot structures to map these valence electrons in order to identify stable electron

### 19.2 Chemical Formulas

In the previous section, you learned how and why atoms form chemical bonds with one another. You also know that atoms combine in certain ratios with other atoms. These ratios determine the chemical formula

### Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.

Introduction to Chemistry Exam 2 Practice Problems 1 Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1.Atoms consist principally of what three

Page 1 of 14 Amount of Substance Key terms in this chapter are: Element Compound Mixture Atom Molecule Ion Relative Atomic Mass Avogadro constant Mole Isotope Relative Isotopic Mass Relative Molecular

### SCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, "Chemistry 11", McGraw-Hill Ryerson, 2001

SCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, "Chemistry 11", McGraw-Hill Ryerson, 2001 1. A small pin contains 0.0178 mol of iron. How many atoms of iron are in the pin? 2. A sample

### Periodic Table Questions

Periodic Table Questions 1. The elements characterized as nonmetals are located in the periodic table at the (1) far left; (2) bottom; (3) center; (4) top right. 2. An element that is a liquid at STP is

### Nomenclature of Ionic Compounds

Nomenclature of Ionic Compounds Ionic compounds are composed of ions. An ion is an atom or molecule with an electrical charge. Monatomic ions are formed from single atoms that have gained or lost electrons.

### Which substance contains positive ions immersed in a sea of mobile electrons? A) O2(s) B) Cu(s) C) CuO(s) D) SiO2(s)

BONDING MIDTERM REVIEW 7546-1 - Page 1 1) Which substance contains positive ions immersed in a sea of mobile electrons? A) O2(s) B) Cu(s) C) CuO(s) D) SiO2(s) 2) The bond between hydrogen and oxygen in

### A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together is called a(n)

Chemistry I ATOMIC BONDING PRACTICE QUIZ Mr. Scott Select the best answer. 1) A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together is

### UNIT (2) ATOMS AND ELEMENTS

UNIT (2) ATOMS AND ELEMENTS 2.1 Elements An element is a fundamental substance that cannot be broken down by chemical means into simpler substances. Each element is represented by an abbreviation called

### Chapter 2 Atoms, Ions, and the Periodic Table

Chapter 2 Atoms, Ions, and the Periodic Table 2.1 (a) neutron; (b) law of conservation of mass; (c) proton; (d) main-group element; (e) relative atomic mass; (f) mass number; (g) isotope; (h) cation; (i)

Contents Getting the most from this book...4 About this book....5 Content Guidance Topic 1 Atomic structure and the periodic table...8 Topic 2 Bonding and structure...14 Topic 2A Bonding....14 Topic 2B

### (b) Formation of calcium chloride:

Chapter 2: Chemical Compounds and Bonding Section 2.1: Ionic Compounds, pages 22 23 1. An ionic compound combines a metal and a non-metal joined together by an ionic bond. 2. An electrostatic force holds

### Atomic Structure. Name Mass Charge Location Protons 1 +1 Nucleus Neutrons 1 0 Nucleus Electrons 1/1837-1 Orbit nucleus in outer shells

Atomic Structure called nucleons Name Mass Charge Location Protons 1 +1 Nucleus Neutrons 1 0 Nucleus Electrons 1/1837-1 Orbit nucleus in outer shells The number of protons equals the atomic number This

### Aqueous Solutions. Water is the dissolving medium, or solvent. Some Properties of Water. A Solute. Types of Chemical Reactions.

Aqueous Solutions and Solution Stoichiometry Water is the dissolving medium, or solvent. Some Properties of Water Water is bent or V-shaped. The O-H bonds are covalent. Water is a polar molecule. Hydration

### Chemistry Post-Enrolment Worksheet

Name: Chemistry Post-Enrolment Worksheet The purpose of this worksheet is to get you to recap some of the fundamental concepts that you studied at GCSE and introduce some of the concepts that will be part

### 7) How many electrons are in the second energy level for an atom of N? A) 5 B) 6 C) 4 D) 8

HOMEWORK CHEM 107 Chapter 3 Compounds Putting Particles Together 3.1 Multiple-Choice 1) How many electrons are in the highest energy level of sulfur? A) 2 B) 4 C) 6 D) 8 2) An atom of phosphorous has how

### Molecules, Compounds, and Chemical Equations (Chapter 3)

Molecules, Compounds, and Chemical Equations (Chapter 3) Chemical Compounds 1. Classification of Elements and Compounds Types of Pure Substances (Figure 3.4) Elements -- made up of only one type of atom

### EDEXCEL IGCSE chemistry (separate award)

EDEXCEL IGCSE chemistry (separate award) Section 1: Principles of chemistry a) States of matter 1.1 understand the arrangement, movement and energy of the particles in each of the three states of matter:

### Test Bank - Chapter 4 Multiple Choice

Test Bank - Chapter 4 The questions in the test bank cover the concepts from the lessons in Chapter 4. Select questions from any of the categories that match the content you covered with students. The

### PART I: MULTIPLE CHOICE (30 multiple choice questions. Each multiple choice question is worth 2 points)

CHEMISTRY 123-07 Midterm #1 Answer key October 14, 2010 Statistics: Average: 74 p (74%); Highest: 97 p (95%); Lowest: 33 p (33%) Number of students performing at or above average: 67 (57%) Number of students

### stoichiometry = the numerical relationships between chemical amounts in a reaction.

1 REACTIONS AND YIELD ANSWERS stoichiometry = the numerical relationships between chemical amounts in a reaction. 2C 8 H 18 (l) + 25O 2 16CO 2 (g) + 18H 2 O(g) From the equation, 16 moles of CO 2 (a greenhouse

### Chapter 8: Chemical Equations and Reactions

Chapter 8: Chemical Equations and Reactions I. Describing Chemical Reactions A. A chemical reaction is the process by which one or more substances are changed into one or more different substances. A chemical

### Chemical Reactions in Water Ron Robertson

Chemical Reactions in Water Ron Robertson r2 f:\files\courses\1110-20\2010 possible slides for web\waterchemtrans.doc Properties of Compounds in Water Electrolytes and nonelectrolytes Water soluble compounds

### Sample Exercise 8.1 Magnitudes of Lattice Energies

Sample Exercise 8.1 Magnitudes of Lattice Energies Without consulting Table 8.2, arrange the following ionic compounds in order of increasing lattice energy: NaF, CsI, and CaO. Analyze: From the formulas

### Molarity of Ions in Solution

APPENDIX A Molarity of Ions in Solution ften it is necessary to calculate not only the concentration (in molarity) of a compound in aqueous solution but also the concentration of each ion in aqueous solution.

### Exercise 3.5 - Naming Binary Covalent Compounds:

Chapter Exercise Key 1 Chapter Exercise Key Exercise.1 Classifying Compounds: Classify each of the following substances as either a molecular compound or an ionic compound. a. formaldehyde, CH 2 O (used

### 2 The Structure of Atoms

CHAPTER 4 2 The Structure of Atoms SECTION Atoms KEY IDEAS As you read this section, keep these questions in mind: What do atoms of the same element have in common? What are isotopes? How is an element

### Chapter 2: The Chemical Context of Life

Chapter 2: The Chemical Context of Life Name Period This chapter covers the basics that you may have learned in your chemistry class. Whether your teacher goes over this chapter, or assigns it for you

### 2. ATOMIC, MOLECULAR AND EQUIVALENT MASSES

2. ATOMIC, MOLECULAR AND EQUIVALENT MASSES INTRODUCTION: EQUIVALENT WEIGHT Since hydrogen is the lightest of all elements, it was chosen as a standard for determination of equivalent weights. On this basis,

### Unit 9 Stoichiometry Notes (The Mole Continues)

Unit 9 Stoichiometry Notes (The Mole Continues) is a big word for a process that chemist s use to calculate amounts in reactions. It makes use of the coefficient ratio set up by balanced reaction equations

### Sample Exercise 2.1 Illustrating the Size of an Atom

Sample Exercise 2.1 Illustrating the Size of an Atom The diameter of a US penny is 19 mm. The diameter of a silver atom, by comparison, is only 2.88 Å. How many silver atoms could be arranged side by side

### 47374_04_p25-32.qxd 2/9/07 7:50 AM Page 25. 4 Atoms and Elements

47374_04_p25-32.qxd 2/9/07 7:50 AM Page 25 4 Atoms and Elements 4.1 a. Cu b. Si c. K d. N e. Fe f. Ba g. Pb h. Sr 4.2 a. O b. Li c. S d. Al e. H f. Ne g. Sn h. Au 4.3 a. carbon b. chlorine c. iodine d.

### Study Guide For Chapter 7

Name: Class: Date: ID: A Study Guide For Chapter 7 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The number of atoms in a mole of any pure substance

### (1) e.g. H hydrogen that has lost 1 electron c. anion - negatively charged atoms that gain electrons 16-2. (1) e.g. HCO 3 bicarbonate anion

GS106 Chemical Bonds and Chemistry of Water c:wou:gs106:sp2002:chem.wpd I. Introduction A. Hierarchy of chemical substances 1. atoms of elements - smallest particles of matter with unique physical and

### Balancing Chemical Equations Worksheet

Balancing Chemical Equations Worksheet Student Instructions 1. Identify the reactants and products and write a word equation. 2. Write the correct chemical formula for each of the reactants and the products.

### Chemistry. The student will be able to identify and apply basic safety procedures and identify basic equipment.

Chemistry UNIT I: Introduction to Chemistry The student will be able to describe what chemistry is and its scope. a. Define chemistry. b. Explain that chemistry overlaps many other areas of science. The

### CHEM 150 Exam 1 KEY Name Multiple Choice

CEM 150 Exam 1 KEY Name Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. _B 1. Which of the following is synonymous with "fact"? a. a hypothesis

### CHEMICAL NAMES AND FORMULAS

6 CEMICAL NAMES AND FORMULAS SECTION 6.1 INTRODUCTION TO CEMICAL BONDING (pages 133 137) This section explains how to distinguish between ionic and molecular compounds. It also defines cation and anion

### hij GCSE Additional Science Chemistry 2 Higher Tier Chemistry 2H SPECIMEN MARK SCHEME Version 1.0

hij GCSE Additional Science Chemistry 2 Higher Tier Chemistry 2H SPECIMEN MARK SCHEME Version.0 Copyright 20 AQA and its licensors. All rights reserved. The Assessment and Qualifications Alliance (AQA)

### Unit 6 The Mole Concept

Chemistry Form 3 Page 62 Ms. R. Buttigieg Unit 6 The Mole Concept See Chemistry for You Chapter 28 pg. 352-363 See GCSE Chemistry Chapter 5 pg. 70-79 6.1 Relative atomic mass. The relative atomic mass

### Coimisiún na Scrúduithe Stáit State Examinations Commission

2015. M33 Coimisiún na Scrúduithe Stáit State Examinations Commission LEAVING CERTIFICATE EXAMINATION, 2015 CHEMISTRY ORDINARY LEVEL TUESDAY, 16 JUNE AFTERNOON 2.00 TO 5.00 400 MARKS Answer eight questions

### Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test

Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test NAME Section 7.1 The Mole: A Measurement of Matter A. What is a mole? 1. Chemistry is a quantitative science. What does this term mean?

### CHEMISTRY BONDING REVIEW

Answer the following questions. CHEMISTRY BONDING REVIEW 1. What are the three kinds of bonds which can form between atoms? The three types of Bonds are Covalent, Ionic and Metallic. Name Date Block 2.

### HOMEWORK 4A. Definitions. Oxidation-Reduction Reactions. Questions

HOMEWORK 4A Oxidation-Reduction Reactions 1. Indicate whether a reaction will occur or not in each of following. Wtiring a balcnced equation is not necessary. (a) Magnesium metal is added to hydrochloric

### Ionic and Metallic Bonding

Ionic and Metallic Bonding BNDING AND INTERACTINS 71 Ions For students using the Foundation edition, assign problems 1, 3 5, 7 12, 14, 15, 18 20 Essential Understanding Ions form when atoms gain or lose

### 19.1 Bonding and Molecules

Most of the matter around you and inside of you is in the form of compounds. For example, your body is about 80 percent water. You learned in the last unit that water, H 2 O, is made up of hydrogen and

### 2014 Spring CHEM101 Ch1-2 Review Worksheet Modified by Dr. Cheng-Yu Lai,

Ch1 1) Which of the following underlined items is not an intensive property? A) A chemical reaction requires 3.00 g of oxygen. B) The density of helium at 25 C is 1.64 10-4 g/cm3. C) The melting point

### Number of moles of solute = Concentration (mol. L ) x Volume of solution (litres) or n = C x V

44 CALCULATIONS INVOLVING SOLUTIONS INTRODUCTION AND DEFINITIONS Many chemical reactions take place in aqueous (water) solution. Quantities of such solutions are measured as volumes, while the amounts

### CHAPTER 5: MOLECULES AND COMPOUNDS

CHAPTER 5: MOLECULES AND COMPOUNDS Problems: 1-6, 9-13, 16, 20, 31-40, 43-64, 65 (a,b,c,e), 66(a-d,f), 69(a-d,f), 70(a-e), 71-78, 81-82, 87-96 A compound will display the same properties (e.g. melting

### Elements, Atoms & Ions

Introductory Chemistry: A Foundation FOURTH EDITION by Steven S. Zumdahl University of Illinois Elements, Atoms & Ions Chapter 4 1 2 Elements Aims: To learn about the relative abundances of the elements,

### Bonding Practice Problems

NAME 1. When compared to H 2 S, H 2 O has a higher 8. Given the Lewis electron-dot diagram: boiling point because H 2 O contains stronger metallic bonds covalent bonds ionic bonds hydrogen bonds 2. Which

### Writing, Balancing and Predicting Products of Chemical Reactions.

Writing, Balancing and Predicting Products of Chemical Reactions. A chemical equation is a concise shorthand expression which represents the relative amount of reactants and products involved in a chemical

### @ Oxford Fajar Sdn. Bhd. (008974-T) 2012. Matter. 1.1 Atoms and Molecules 1.2 Mole Concept 1.3 Stoichiometry

1 Matter 1.1 Atoms and Molecules 1.2 Mole Concept 1.3 Stoichiometry 2 Chemistry for Matriculation Semester 1 1.1 Atoms and Molecules LEARNING OUTCOMES Describe proton, electron and neutron in terms of

### Name Block Date Ch 17 Atomic Nature of Matter Notes Mrs. Peck. atoms- the smallest particle of an element that can be identified with that element

Name Block Date Ch 17 Atomic Nature of Matter Notes Mrs. Peck atoms- the smallest particle of an element that can be identified with that element are the building blocks of matter consists of protons and

### Question Bank Electrolysis

Question Bank Electrolysis 1. (a) What do you understand by the terms (i) electrolytes (ii) non-electrolytes? (b) Arrange electrolytes and non-electrolytes from the following substances (i) sugar solution

### Nomenclature and the Periodic Table To name compounds and to determine molecular formulae from names a knowledge of the periodic table is helpful.

Nomenclature and the Periodic Table To name compounds and to determine molecular formulae from names a knowledge of the periodic table is helpful. Atomic Number = number of protons Mass Number = number

### Writing and Balancing Chemical Equations

Name Writing and Balancing Chemical Equations Period When a substance undergoes a chemical reaction, chemical bonds are broken and new bonds are formed. This results in one or more new substances, often

### Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1. A chemical equation. (C-4.4)

Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1 1. 2. 3. 4. 5. 6. Question What is a symbolic representation of a chemical reaction? What 3 things (values) is a mole of a chemical

### neutrons are present?

AP Chem Summer Assignment Worksheet #1 Atomic Structure 1. a) For the ion 39 K +, state how many electrons, how many protons, and how many 19 neutrons are present? b) Which of these particles has the smallest

### Trends of the Periodic Table Diary

Trends of the Periodic Table Diary Trends are patterns of behaviors that atoms on the periodic table of elements follow. Trends hold true most of the time, but there are exceptions, or blips, where the

### PERIODIC TABLE OF GROUPS OF ELEMENTS Elements can be classified using two different schemes.

1 PERIODIC TABLE OF GROUPS OF ELEMENTS Elements can be classified using two different schemes. Metal Nonmetal Scheme (based on physical properties) Metals - most elements are metals - elements on left

### The Mole Concept. The Mole. Masses of molecules

The Mole Concept Ron Robertson r2 c:\files\courses\1110-20\2010 final slides for web\mole concept.docx The Mole The mole is a unit of measurement equal to 6.022 x 10 23 things (to 4 sf) just like there

### 100% ionic compounds do not exist but predominantly ionic compounds are formed when metals combine with non-metals.

2.21 Ionic Bonding 100% ionic compounds do not exist but predominantly ionic compounds are formed when metals combine with non-metals. Forming ions Metal atoms lose electrons to form +ve ions. Non-metal