MIDTERM DATES: Atoms and the Periodic Table Define and identify elements and compounds

Transcription

1 Chemistry 10 with Mrs. Howland MIDTERM STUDY GUIDE FORMAT: 60 multiple choice (1 pt each) 5 short answer or calculation problem OPEN RESPONSE (8 pts each) MIDTERM DATES: MY MIDTERM Lab Safety and Equipment / Metrics & Measurement Identify the EIGHT (8) pieces of common laboratory equipment we learned in class. Convert between units of measure within the metric system (i.e. cm to m, km to mm, etc.) Explain the difference between precision and accuracy Calculate percent error. Explain what data represents the expected and experimental values. Identify # of significant figures in a given number Write a number in scientific notation Properties of Matter Classify matter according to properties (HINT: Use concepts from flowchart for physical/chemical, mixtures, homogenous/heterogeneous mixtures, substances, atoms, compounds, etc.). Provide examples for each type of classification. Describe colloid, solution, and alloy. Identify physical properties (i.e. melting point, boiling point, ductility, density, luster, solubility, hardness, color, odor, malleability, viscosity) Identify chemical properties (i.e. flammability, corrosiveness, reactivity, rust, ph,) Identify physical and chemical changes and explain differences between them Density Define and identify the correct units for mass, volume, and density Explain how to measure the mass and volume for blocks, cylinders, and irregularly-shaped objects Calculate volume of blocks, cylinders, and irregularly-shaped objects Identify the formula and variables for density, including correct units Use the formula for density (density = mass/volume) to solve for density, mass, or volume from word problems Atoms and the Periodic Table Define and identify elements and compounds

2 Define and identify atoms, ions, and isotopes Define and determine the atomic mass, atomic number, mass number, # protons, # neutrons, and # electrons for a given element Define and explain the characteristics of protons, electrons, and neutrons Explain the basics of atomic theory (Bohr model, etc.) Define properties: malleable, ductile, conductor Classify elements based on location on periodic table, explain the characteristics of each (metals, metalloids, non-metals, alkali metals, alkaline earth metals, halogens, noble gases, transition metals, inner transition metals (rare earth metals) Define atomic radius, ionization energy, electron affinity, electronegativity Compare groups of elements and classify (high/low or small/big) according to trends for atomic radius, ionization energy, electron affinity, electronegativity Chemical Bonding Explain the octet rule Define valence electrons and identify # of valence electrons for representative elements using the periodic table Define anions and cations and explain how they get their charges Explain which types of elements tend to form ionic bonds and the characteristics of ionic compounds Explain which types of elements tend to form covalent bonds and the characteristics of molecular compounds Explain the characteristics of substances with metallic bonds Draw Lewis Dot structures for elements, ionic compounds, and molecular compounds Nomenclature and Chemical Formulas Predict ionic charge for monoatomic ions using periodic table Identify monatomic and polyatomic ions (using list of 10 common polyatomic ions) Name ionic compounds from a given chemical formula Use criss-cross method to write chemical formula for ionic compounds from a given chemical name Explain how charges on ions cancel out to form a neutral ionic compounds, and why Name binary molecular compounds from a given formula (HINT: use prefixes correctly, following all rules) Write chemical formula for binary molecular compounds from a given compound name Chemical Quantities (partial unit) Define mole and Avogadro s number Determine/calculate molar mass for elements and compounds Identify conversion units for Avogadro s number and the mole Identify conversion units for molar mass and the mole Convert single-step dimensional analysis between particles and moles, and between moles and mass OPEN RESPONSE QUESTIONS (FIVE ~5~ OF THESE WILL BE ON THE MIDTERM!)

3 Lab Safety and Equipment / Metrics & Measurement 1) Accuracy is often expressed as an average of several measurements. Look at the target below. In your opinion, how well do the measurements on the target represent: (Justify your opinion.) a. Accuracy? b. Precision? Properties of Matter 1) Several properties for zinc (Zn) are listed below: brittle at room temperature, but malleable between 100 C and 150 C bluish-white in color burns in air at high temperatures, giving off zinc oxide (ZnO) gas conducts heat and electricity sinks in water (density) reacts with acids and bases exposed surfaces tarnish in moist air a. Identify two physical properties of zinc from the list. Explain why the properties you identified are physical properties and not chemical properties. b. Identify two chemical properties of zinc from the list. Explain why the properties you identified are chemical properties and not physical properties. Density

4 1) A scientist has three unlabeled samples of pure metals. He wants to determine the identity of each metal. a. Identify which one of the following properties the scientist should use to determine the identity of the pure metal in each sample: color, melting point, mass, or volume. b. Explain why the property you identified in part (a) can be used to determine the identity of the pure metal in each sample. The scientist cuts each of the samples of pure metal into two smaller pieces. c. Is the property that is used to determine the identity of the metal affected when each sample is cut into two pieces? Explain your answer The scientist can also use density to determine the identity of the pure metal in each sample. d. Describe how the scientist can determine the density of the pure metal in each sample. Atoms and the Periodic Table 1) Chlorine and bromine are both found in the same group in the periodic table. Name this group. Are these elements metals or nonmetals? How many valence electrons do they have? Name a property that these two elements would be expected to share.

5 2) Since elements are listed in the periodic table in order of increasing atomic number and arranged so that elements with similar properties fall into the same group, the periodic table can be used to predict similarities and differences between elements. a. Bromine and fluorine are both in group 17 (7A) of the periodic table. Describe two properties of bromine and fluorine that are the same. b. Bromine and fluorine are in different periods in the periodic table. Describe two properties of bromine and fluorine that are different. c. Based on their positions in the periodic table, bromine and fluorine are most likely to form ionic compounds with an element from which group: group 1 (1A), group 14 (4A), or group 18 (8A)? Explain your choice. Chemical Bonding 1) Draw the Lewis Dot Diagram for MgCl 2, then explain: a. How many valence electrons do each element start with? b. What is their ionic charge (AFTER bonding)? c. Are electrons shared or transferred? How? 2) Draw the Lewis Dot Diagram for SO 3, then explain: a. How many valence electrons do each element start with? b. Do the atoms carry a charge? Why or why not? c. Are electrons shared or transferred? How?

6 Chemical Quantities 1) Determine the molar mass for given compound (compound not announced in advance) a. Calculate the moles, given a mass (given mass not announced in advance; example: How many moles of NaCl are in 35g?) b. Calculate the number of particles PRACTICE PROBLEMS: 1) What is the difference between accuracy and precision? 2. What is the formula for calculating percent error? 3. If you measure the mass of a book at 125 grams and the accepted value is really 130 grams, what is your percent error? 4. Convert 125 centimeters (cm) to kilometers (km). 5. Convert meters (m) to centimeters (cm). 6. What is the number of significant figures in each of the following measurements? a g d m b. 7.3 m e g c. 410 cm f s

7 7. Re-write each of the following in scientific notation: a c b d Classify the following properties as chemical or physical. a. blue color b. flammability c. ability to react with acids d. density 9. Classify the following changes as chemical or physical. a. ice melting b. fermentation c. iron rusts d. dissolving in water 10. Define element and compound 11. What is the difference between a substance and a mixture? 12. Give an example of: a. heterogeneous mixture and a homogenous mixture b. What is a colloid? An alloy? Give an example of each. 13. What is the formula for density? 14) What is the density of CO gas if g occupies a volume of 100mL? 15) A block of wood 3cm on each side has a mass of 27 g. What is the density of the block? (Hint, don t forget to find the volume of the wood.)

8 16) An irregularly shaped stone was lowered into a graduated cylinder holding a volume of water equal to 2mL.The height of the water rose to 7mL. If the mass of the stone was 25g, what was its density? (HINT: find the volume of the stone by determining the difference in the water s measurement in the graduated cylinder). 17) List the 3 subatomic particles, their charges, their relative masses and their location in the atom. 18) Complete the following chart: Element Name Atomic # Atomic Mass # protons # electrons (neutral atom) # neutrons Symbol 6 12 Cl Uranium 10 19) What is an ion? 20) What is the difference between a cation and an anion? 21) What is an isotope? 22) What is an atom? How does it compare to a compound? To an ion?

9 23) Define each of the following and explain their periodic trend (how they change acrossthe periodic table): a. electronegativity b. ionization energy c. electron affinity d. atomic radius 24) Distinguish between groups and periods. 25) Which of the following elements have similar properties? Why? Ca, K, Kr, Cl, Br 26) Give the names of the following groups. a. Group 1 b. Group17 c. Group 2 d. Group 18 27) Where are the transition metals? Inner transition metals? 28) Which Group contains the most reactive metals? Reactive nonmetals?

10 29) Give the group and period for the following elements: a. helium b. bromine - c. calcium - d. copper 30) Identify the number of valence electrons present in the following elements: a. Radium b. Iodine c. Cesium d. Aluminum e. vanadium 31) What is the approximate molar mass of Ca(NO3)2? a. 70 b. 82 c. 102 d. 150 e ) Calculate the molar mass for each of the following: a. KMn4 : b. KCl: c. Na2SO4 : 33) Name each of the following ionic compounds: a. LiBr b. MgCl2 is c. ZnSO4 is 34) Name each of the following covalent compounds: a. P2O3 is b. PCl5 is c. OF2 is 35) Write the formula for each of the following: a. diphosphorus pentoxide is b. calcium chloride is 36) Identify the properties of ionic compounds? Covalent compounds?

11 37) Draw the Lewis Structures for the following ionic compounds: a. sodium chloride b. magnesium fluoride 38) Draw the Lewis Structures for the following molecular compounds: a. Carbon monoxide b. Nitrogen trioxide 39) What is the value of Avogadro s number? 40) How many moles of chromate ions are in 5.50 moles of Pb(CrO 4 ) 2? 41) Calculate the mass of 3.57 moles of aluminum. 42) How many moles are in 25.0 g of Fe 2 O 3? 43) Calculate the number atoms in 2.50 moles of Zinc.