GCSE Mark Scheme Chemistry 1 Foundation only questions Summer 2010

Transcription

1 GCSE Mark Scheme Chemistry 1 Foundation only questions Summer (i) 3 yes B (1) no C (1) metal D (1) (ii) 1 conducts heat / malleable / ductile high boiling point conducts sonorous high density 1

2 2 (i) 1 plates tectonic plates (ii) 1 slowly (iii) 2 earthquakes (1) volcanoes (1) 2

3 3 (i) 1 iron / oxygen Fe / O 2 iron powder FE / O (ii) 1 iron oxide FeO / Fe 2 O 3 oxide (iii) 1 high temperature burns / very hot / hot needs qualifying (iv) 2 identifying the two substances lithium carbonate and copper chloride (1) identify the correct positions for the substances lithium carbonate at the top and copper chloride at the bottom of the sparkler (1) 3

4 4 (i) 2 hydrogen (1) oxygen (1) H 2 / H O 2 / O (ii) 1 NH 4 NO 3 must be correct ammonium nitrate (iii) 1 D 4

5 5 (i) 1 75 nm (ii) 2 to coat the inner surface of refrigerators (1) in sterilizing sprays to clean operating theatres in hospitals (1) 5

6 6 (i) / 346 (ii) I 1 increase II 1 increases III 1 global warming greenhouse effect climate change 6

7 7 (i) 2 H 3 PO 4 (2) [ HPO (1) / 3 4 (1)] (ii) I 1 MgO Mg 2+ O 2- II 1 CaBr 2 Ca 2+ Br 2 / Ca 2+ (Br ) 2 7

8 8 (i) 3 all points plotted correctly (2) any five points plotted correctly (1) curve of best fit through all points (1) consequential curve (ii) 1 38 ± 1.0 consequential (iii) minute (iv) 2 40 (1) volume of gas depends on the mass of magnesium used / acid in excess in both experiments (1) 8

9 GCSE Mark Scheme Chemistry 1 Common questions Summer (i) 2 B and F (1) both have one electron in their outer shell / same number of electrons in their outer shell (1) sodium and potassium / Na and K / 2, 8, 1 and 2, 8, 8, 1 'finishes in 1' both in Group 1 (ii) 2 A (1) oxygen / O / O 2 2, 6 two electron shells (1) two orbits has two numbers (iii) I 1 B 2, 8, 1 Na II 1 fluorine / bromine / iodine / astatine F / Br / I / At F 2 / Br 2 / I 2 / At 2 chlorine / Cl / Cl 2 9

10 10 2 (i) 2 A (1) biggest increase in temperature (1) temperature increases highest final temperature (ii) 2 bubbles / colour change / precipitate formation any two for (1) each fizzing / brown solid formed colour new substances / products formed substance disappears 10

11 11 3 (i) I 1 2Na + Cl 2 2NaCl i.e. fourth equation (1) II 1 yellow orange (ii) I 2 potassium iodide + chlorine (1) potassium chloride + iodine (1) KI + Cl 2 (1) KCl + I 2 (1) (ignore balancing) KI solution / CI 2 gas potassium iodide solution / chlorine gas II 1 chlorine is toxic poisonous iodine is toxic harmful / dangerous 11

12 GCSE Mark Scheme Chemistry 1 Higher only questions Summer (i) I 1 magma molten rock lava II 1 igneous (ii) 1 earthquakes mountain ranges ocean trenches oceanic rifts subduction / tsunami 12

13 5 (i) 2 B (1) conducts electricity (1) density needs qualifying e.g. less dense than water mp 98 / density 0.97 (ii) 2 A (1) boiling point lower than room temperature or 20 o C (1) density needs qualifying e.g. very low gas at room temperature gas 13

14 6 (i) 1 any number between 1 and 100 / range any appropriate range (ii) 2 sterilising sprays (to clean operating theatres in hospital) / refrigerator surfaces / wound dressing / deodorant socks / hospital clothing any two for (1) each 14

15 FT HT Sub-section Mark Answer Accept Neutral answer Do not accept 7 (i) I 1 increase II = 43 ± 0.5 per reading therefore ± 1.0 for change (range 42 44) (ii) 2 increased burning of (fossil) fuels (or named fuel) (1) more cars more power stations deforestation (1) (iii) I 1 increase in winter / decrease in summer II 1 more fuel burnt in winter / fewer plants in winter / less photosynthesis in winter / seasonal uptake by plants less in winter less sunshine in winter any one 15

16 8 (i) I 2 curve to the right of graph A (1) aiming towards 30 cm 3 / levelling off at 30 cm 3 (1) II 2 curve to the left of graph A (1) levelling off at 60 cm 3 before 30 s (1) (ii) 2 more energy / move faster (1) greater chance of a collision / more (effective) collisions in a unit /set time (1) more collisions / successful collisions 16

17 9 (i) I 2 4(413) + 2(498) (1) 2648 (1) answer only (2) II 2 2(805) + 4(464) (1) 3466 (1) answer only (2) (ii) 1 energy needed to break the bonds is less than the energy given out in making bonds / 818 / overall energy change has negative value any one more energy given out than taken in 818 / heat given out 17

18 10 (i) I 1 potassium K II 3 2K + 2H 2 O 2KOH + H 2 2M + 2H 2 O 2MOH + H 2 consequential marking for Group 1 element reactants (1) products (1) balancing if both reactants and products are correct (1) (ii) I 1 Na 2 CO 3 (1) Na + 2CO 3 2 / (Na + ) 2 CO 3 2 II 3 add hydrochloric acid (to both) (1) sodium carbonate bubbles/fizzes (1) no observation seen with sodium chloride (1) or add (ph) indicator (to both) (1) sodium carbonate ph > 7 / alkaline (1) sodium chloride ph = 7 / neutral (1) silver nitrate (1) white ppt with NaCl (1) -2 max 18