Q. The diagrams show five different atoms, A, B, C, D and E. (a) Which atom, A, B, C, D or E: (i) has an atomic number (proton number) of 3 Atom () has a mass number of 2 Atom () (iii) is in Group 2 of the periodic table? Atom () Atom (b) Which two atoms from A, B, C, D and E are isotopes of the same element? and Atom Page
() (c) Which particle in an atom has a negative charge?... () (Total 5 marks) Q2. Pure carbon can exist in two forms, diamond and graphite. (a) Complete the diagram to show the electronic structure of a carbon atom. A carbon atom has 6 electrons. Show the electrons as crosses (x). () (b) A drill bit is used to cut holes through materials. The cutting end of this drill bit is covered with very small diamonds. Page 2
Flickr By Wanderlinse [CC By 2.0], via (i) What property of diamond makes it suitable for use on the cutting end of a drill bit? () Explain, as fully as you can, why diamond has this property. Use your knowledge of the structure and bonding of diamond and the information shown opposite to help you to answer this question. (3) (c) Explain why graphite is a good conductor of electricity and why diamond does not conduct electricity.... Page 3
.................. St Edmund's Girls' School... (3) (Total 8 marks) Q3.This question is about atoms and molecules. (a) Complete the table to show the relative masses of the particles in atoms. Name of particle Relative mass Proton... Neutron Electron... (2) (b) The diagram shows an oxygen atom. Use the correct number to complete each sentence. 8 6 8 24 Page 4
The atomic (proton) number of the oxygen atom shown above is.... The mass number of the oxygen atom shown above is.... (2) (c) (i) Draw a ring around the correct answer to complete each sentence. isotopes. Oxygen atoms with different numbers of neutrons are called molecules. polymers. () An oxygen atom with a different number of neutrons has 0 neutrons. Draw a ring around the symbol which represents this atom. () (d) A water molecule contains hydrogen and oxygen atoms. (i) Use the correct answer to complete the sentence. a compound an element a mixture Water is.... () Draw a ring around the correct structure of a water molecule. H O H O H H O H O () (iii) Draw a ring around the type of bonding in a water molecule. covalent ionic metallic () Page 5
(iv) Draw a ring around the correct answer to complete each sentence. gaining The bonds in a water molecule are formed by losing electrons. sharing () (Total 0 marks) Q4.The diagram shows a small part of the structure of silicon dioxide. (a) Use the diagram above to answer the question. Draw a ring around the correct answer to complete each sentence. two In silicon dioxide, each silicon atom is bonded with three oxygen atoms. four ionic. The bonds in silicon dioxide are covalent. metallic. (2) (b) Page 6
Oleksiy Mark/iStock Silicon dioxide is used as the inside layer of furnaces. Suggest why....... () (c) Nanowires can be made from silicon dioxide. Draw a ring around the correct answer to complete the sentence. brittle. The word nano means the wires are very thick. thin. () (Total 4 marks) Q5.The following steps show how to use a type of glue. Step Measure out equal amounts of the liquids from tubes A and B. Page 7
Step 2 Mix the liquids to make the glue. Put a thin layer of the glue onto each of the surfaces to be joined. Step 3 Put the pieces together and hold them with tape. Step 4 Leave the glue to set. (a) When liquids A and B are mixed a chemical reaction takes place. This reaction is exothermic. What does exothermic mean?............ (2) Page 8
(b) St Edmund's Girls' School The time taken for the glue to set at different temperatures is given in the table below. Temperature in C Time taken for the glue to set 20 3 days 60 6 hours 90 hour (i) Use the correct answer from the box to complete each sentence. decreases increases stays the same When the temperature is increased the time taken for the glue to set When the temperature is increased the rate of the setting reaction (2) Tick ( ) two reasons why an increase in temperature affects the rate of reaction. Reason Tick ( ) It gives the particles more energy It increases the concentration of the particles It increases the surface area of the particles It makes the particles move faster (2) (Total 6 marks) Q6. (a) The symbol equation for the decomposition of hydrogen peroxide is: Page 9
2H2O2 2H2O + O2 Complete the word equation for the decomposition of hydrogen peroxide. Hydrogen peroxide... +... () (b) A student did an experiment to see how quickly hydrogen peroxide decomposes. The student used the apparatus shown below to measure the volume of oxygen. (i) Draw a straight line of best fit to complete the graph. () Page 0
Draw a circle around the anomalous point on the graph. () (iii) What is the volume of oxygen given off after 5 seconds?... cm 3 () (iv) How did the volume of oxygen change between 0 and 25 seconds? () (c) The student wanted to make the reaction faster. Draw a ring around the correct answer to complete each sentence. higher. (i) To make the reaction faster, the temperature should be lower. the same. () more dilute. To make the reaction faster, the hydrogen peroxide should be more concentrated. the same. () (d) The diagram represents the bonding in oxygen. O=O Page
Draw a ring around the correct answer to complete each sentence. St Edmund's Girls' School share (i) When two oxygen atoms bond, the atoms transfer electrons. delocalise () ionic The oxygen atoms are joined by metallic bonds. covalent () simple molecules. (iii) Oxygen is made of a giant lattice. macromolecules. () (e) When hydrogen peroxide decomposes water is produced. Which two statements in the table explain why water is a liquid at room temperature? Tick ( ) the two statements. Water has a boiling point of 00 C. Water is made of ions. Statement Tick ( ) Page 2
Water has a melting point lower than room temperature. Water has a giant covalent structure. (2) (Total 2 marks) Q7.(a) Some students did an experiment to find the temperature change when hydrochloric acid reacts with sodium hydrogencarbonate. The results are in the table. Number of spatula measures of sodium hydrogencarbonate Start temperature in C Final temperature in C Change in temperature in C 2 20 6 4 4 20 4 6 6 9 8 8 20 0 0 0 9 9 0 2 20 0 0 (i) Describe, as fully as you can, the trends shown in the students results. Page 3
(3) State the type of energy transfer for this reaction. () (b) Sodium hydrogencarbonate is used as baking powder for making cakes. When the cake mixture is baked the sodium hydrogencarbonate decomposes. The equation for the reaction is: (i) The cake mixture rises when baked. Use the equation to suggest why. Page 4 Michael Valdez/iStock
St Edmund's Girls' School () The same reaction can be reversed to produce sodium hydrogencarbonate from sodium carbonate. Na2CO3 + H2O + CO2 2NaHC O3 Do the reactants need to be heated? Give a reason for your answer. () (c) (i) Calculate the relative formula mass of sodium hydrogencarbonate (NaHCO3). Relative atomic masses (Ar): H=; C=2; O=6; Na=23 Relative formula mass (Mr) =... (2) Calculate the percentage by mass of carbon in sodium hydrogencarbonate. Percentage of carbon =... % () (Total 9 marks) Page 5
M. (a) (i) B A (iii) C (b) D and E (c) electron [5] M2. (a) 2,4 (drawn as crosses) on shells accept dots / e / - etc. (b) (i) hard allow rigid / high melting point do not allow references to bonding ignore strong ignore unreactive ignore structure any three from max 2 if ionic / metallic / molecule / intermolecular bonds or incorrect number of bonds Page 6
giant structure / lattice / macromolecular allow many bonds St Edmund's Girls' School covalent (bonds) (covalent) bonds are strong accept needs lots of energy to break bonds (owtte) (each) carbon / atom forms four bonds or (each) carbon / atom bonded to four other atoms 3 (c) any three from: max 2 if ionic / ions / metallic / molecule it needs to be qualified graphite has delocalised / free electrons do not accept the electrons move unless qualified (around structure etc) or electrons that can move through / around the structure each carbon is joined to three other carbon atoms allow graphite has three bonds or diamond one electron from each atom is free / delocalised has no free / delocalised electrons do not accept the electrons do not move or no electrons that move around the structure all the electrons are used for bonding allow diamond has 4 bonds or each carbon joined to four other carbon atoms 3 [8] Page 7
M3.(a) proton ignore ± electron very small owtte allow zero allow values from / 800 to / 2000 or 0.0005 0.00055 (b) 8 6 (c) (i) Isotopes (d) (i) compound H-O-H (iii) covalent Page 8
(iv) sharing [0] M4.(a) four covalent (b) because it has a high melting point accept it won t melt accept it won t decompose or react allow withstand high temperatures ignore boiling point (c) thin [4] M5.(a) heat / energy given out / transfers to surroundings the mark for given out / transfers to cannot be awarded without heat / energy allow given off (b) (i) decreases Page 9
increases St Edmund's Girls' School it gives the particles more energy it makes the particles move faster [6] M6. (a) oxygen and water both needed for mark allow hydrogen oxide for water in any order ignore formulae (b) (i) best fit line, omitting point at 0s straight line drawn through all correct points circle around point at 0 s allow any indication (iii) 7.5 allow ecf from candidate s line (iv) increases (with time) accept goes from 0 to 2.5 (c) (i) higher Page 20
more concentrated (d) (i) share covalent (iii) simple molecules (e) Water has a boiling point of 00 C Water has a melting point lower than room temperature [2] M7.(a) (i) the more sodium hydrogencarbonate the greater the temperature change accept examples from the table up to 8 spatula measures accept any correct indication of when change occurs then the temperature change is constant if no marks awarded allow mark for: the more sodium hydrogencarbonate the lower the final temperature Page 2
energy is taken in from the surroundings or endothermic (b) (i) gas / carbon dioxide / steam / water is produced accept carbon dioxide is a gas or steam / water is a gas allow gas / air expands when heated no, because (reaction) is exothermicoryes, to start the reaction allow no, because (reactants) were formed by heating ignore references to cooling (c) (i) 84 correct answer with or without working gains 2 marks if no answer or incorrect answer then evidence of 23 + + 2 + (3 6) gains mark 2 4.29 accept rounding to 4.3 or 4 allow ecf from (c)(i) [9] Page 22