B D A C. response: it mixed with the water.

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1 1. (a) Award ONE mark for correctly completing all four rows of the table: 1 Solid soil vitamin tablet plastic beads salt Beaker B D A C (b) Award ONE mark for a response indicating the solid dissolved: 1 salt/it dissolved; it formed a solution. ONE mark may be awarded for a response stating that the vitamin tablet dissolved if the pupil has identified that the vitamin tablet is in beaker C in part a). response that does not explain what happened to the solid: it disappeared. it mixed with the water. (c) Award ONE mark for: 1 Beaker D. ONE mark may be awarded for: vitamin tablet. (d) Award ONE mark for: 1 (e) Award ONE mark for an indication that Safara should evaporate the water: 1 evaporate the water; by evaporation. ONE mark may be awarded for a response explaining the beaker should be moved to a warmer place and/or left to dry: move the beaker on to a (sunny/warm) John Buchan Middle School 1

2 window sill; put the beaker on a radiator; by heating it. response where it is ambiguous what is evaporating: evaporate the mixture; evaporate it [it refers to the salt]. filter the solution. [5] 2. (a) Award ONE mark for all three liquids correctly identified [in any order]: 1m water; and oil; and vinegar. (b) Award ONE mark for an unambiguous indication of Bag A: 1m Bag A; brown sugar and water. (c) Award ONE mark for an understanding that the fizzing shows that a gas or 1m new material is being made (that is taking up more space): bubbles of gas have been made; gas is being given off; because the bicarbonate and vinegar react. John Buchan Middle School 2

3 the gas spreads out. Do not give credit for a response that includes incorrect science: there is more air [a gas is produced but this is not air]. Do not give credit for an incorrect response that describes a characteristic of one material, rather than the reaction between two materials: soda is fizzy. it is fizzing [given]; it is bubbling [no indication of a new material being made]. (d) Award ONE mark for an unambiguous indication of Bag C: 1m Bag C; bicarbonate of soda and vinegar. 3. (a) (i),(ii) Award ONE mark for each of: 2 sugar salt (b) Award ONE mark for: 1 filter and evaporate [in this order]. (c) Award ONE mark for: 1 solution John Buchan Middle School 3

4 (d) Award ONE mark for an awareness of a limit to the amount of solid which can 1 dissolve in the water: there is a limit to how much/the amount/mass of sugar/solid which can dissolve. the limit has been reached; the water will not hold any more sugar; the water is full up/has no more space; the solution was saturated. Do not give credit for: no more solid will dissolve [given in question]; cannot add any more; there is not enough water. (e) Award ONE mark for an appreciation that twice as much solute will dissolve 1 in twice as much solvent; twice as much sugar would dissolve; 8 (more) spoonfuls; Allow answers between 8 and less than 10 (more) spoonfuls and answers between 16 and less than 20 in total. Do not give credit for: it would all dissolve; 16. [6] John Buchan Middle School 4

5 4. (a) Award ONE mark for indicating the mistake Luis has made, or conversely, 1 indicating how he should take the temperature of the water: the thermometer is out of the water; put the thermometer in the water; leave the thermometer in the water while taking the reading. he has taken it out; he did not leave the thermometer in. response indicating he has removed the thermometer too soon: he has not left it long enough. he should look carefully not enough water. (b) Award ONE mark for recognition of the independent variable, eg: 1 the temperature of (water). heat of water; the warmth of the water. response which does not clearly describe the independent variable: water. Do not give credit for a response that includes incorrect science which redefines the independent variable: amount of water. John Buchan Middle School 5

6 (c) Award ONE mark for an awareness of one of the factors to be controlled: 1 volume of water; amount/kind of water; amount of sugar; type/size of sugar grain; how he stirs; how sugar is added. sugar; containers. response which is ambiguous: keep the water the same. Do not give credit for measurement strategies which would improve accuracy: keep the thermometer in water. (d) Award ONE mark for: 1 40ºC. Do not give credit for: 12ºC. (e) Award ONE mark for: 1 Yes and an indication of how the evidence of temperature and time support the prediction, eg: the time to dissolve gets less as the temperature increases; at the hottest temperature the time is less; when the temperature was 60ºC the sugar dissolved more quickly; at 30ºC it takes more time to dissolve than at 60ºC. it is quickest at 60ºC; the three tests show that the sugar dissolves more quickly when the water is hotter. John Buchan Middle School 6

7 if neither box is ticked, but the creditworthy explanation indicates that Jack s prediction is supported by the evidence, the mark may be awarded. Do not give credit if the no box is ticked. response which restates the time variable: it dissolves more easily. response which does not specify the time variable: the hotter the temperature, the smaller the numbers. response which reads off one set of data without any comparison: because the temperature was 60ºC and it took 10 minutes to dissolve; it s quick at 60ºC. [5] 5. (a) Award TWO marks for all three ticks correctly placed: 2 Material Solid Liquid Gas Citric acid powder Bicarbonate of soda powder Water If you are unable to award two marks, award ONE mark for any two ticks correctly placed. (b) Award TWO marks for a response that describes the following events in the 2 context of the experiment in the given order: 1) the water evaporates; 2) the citric acid remains in the container/dish: evaporate the water and the citric acid will stay in the container; put the water and citric acid mixture somewhere warm. The water will turn to vapour and the citric acid will remain. they heat the mixture. The citric acid powder is left behind. John Buchan Middle School 7

8 or If you are unable to award two marks, award ONE mark for a response 1 that describes one event: evaporate the water from the container; the citric acid forms crystals once the water is gone. a response that indicates they move the container to a warmer place (to increase the rate of evaporation): move the container/mixture to a warmer place; put the bowl on the radiator. Do not credit the first marking point for a response that includes incorrect science indicating the citric acid may evaporate with the water: evaporate the solution. Do not credit the first marking point for an insufficient response that is unclear or ambiguous as to what is evaporating: evaporate it. [4] 6. (a) Award ONE mark for: C. a response within the range of C inclusive. just over one hundred, just over 100 C. (b) Award ONE mark for an indication that the temperature stays 1 constant (while there is water in the container): the temperature will stay the same; the temperature will stay at 102 C until all the water has boiled. it stays at 100 C [if 100 C is given in part a]. John Buchan Middle School 8

9 Give credit for a correct response that goes beyond the key stage 2 programme of study indicating a slight increase in temperature, if qualified by a recognition of the increasing salt concentration: the temperature may increase (slightly) due to the increasing concentration of salt. [2] John Buchan Middle School 9