Question 19N.1B.SL.TZ0.b(i)
| Date | November 2019 | Marks available | [Maximum mark: 3] | Reference code | 19N.1B.SL.TZ0.b(i) |
| Level | SL | Paper | 1B | Time zone | TZ0 |
| Command term | Determine, Show | Question number | b(i) | Adapted from | N/A |
Determine the initial rate of reaction of limestone with nitric acid from the graph.
Show your working on the graph and include the units of the initial rate.
[3]
tangent drawn at time zero ✔
g day−1 ✔
0.16 ✔
NOTE: Accept other reasonable units for initial rate eg, mol dm−3 s−1, mol dm−3 min−1, g s−1 OR g min−1.
M3 can only be awarded if the value corresponds to the correct unit given in M2.
Accept values for the initial rate for M3 in the range: 0.13 − 0.20 g day−1 OR 1.5 × 10−6 g s−1 − 2.3 × 10−6 g s−1 OR 7.5 × 10−8 − 1.2 × 10−7 mol dm−3 s−1 OR 4.5 × 10−6 − 6.9 × 10−6 mol dm−3 min−1 OR 9.0 × 10−5 − 1.4 × 10−4 g min−1 OR a range based on any other reasonable unit for rate.
Ignore any negative rate value.
Award [2 max] for answers such as 0.12/0.11 g day−1, incorrectly obtained by using the first two points on the graph (the average rate between t = 0 and 1 day).
Award [1 max] for correctly calculating any other average rate.
