Chemistry · May / June 2023 · Paper 62 · Question 2
0620
As printed in the paper
The question as text
A student investigates how the rate of the reaction between aqueous iron(III) nitrate and aqueous sodium thiosulfate changes with temperature. The student does five experiments using the apparatus shown in Fig. 2.1. eye 5 cm3 of aqueous sodium thiosulfate printed sheet printed text 50 cm3 of aqueous iron(III) nitrate 100 cm3 beaker Fig. 2.1
Read automatically from the paper; the printed page above is exact.
Show the answer and mark scheme
2(a)[4]
M1 all five times correct (116, 80, 69, 46, 21)
M2 all times shown in seconds only
M3 all temperatures correct (20.5, 27.0, 30.0, 37.0, 46.5)
M4 all temperatures shown to 1 dp
2(b)[4]
M1 y-axis scale in linear and points extend over halfway up scale
M2 and M3 all points plotted correctly
M4 best fit line
2(c)[1]
experiment 5
2(d)[2]
M1 working shown on graph at 55 s
M2 correct value for temperature from their graph
2(e)[2]
M1 insulation / reduces heat loss
M2 temperature remains (more) constant / changes less / does not change / is maintained
2(f)(i)[1]
(burette) (more) accurate (than a measuring cylinder)
2(f)(ii)[1]
reaction starts while still adding the sodium thiosulfate / slow (to add)
2(g)[1]
otherwise it will react while it is being heated / temperature increases while it is reacting / reaction starts at a lower temperature
2(h)[2]
M1 times shorter / decrease
M2 less depth to look through
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