Wzorowane na: Chemistry SL Paper 1B, November 2025, TZ3, pytanie 2(a). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Informacja do zadań 2a-2b.
Two students were asked to determine the concentration of a solution of potassium hydroxide,
Student A measured out the two solutions with a 50 measuring cylinder, combining them in a 150 glass beaker to give eleven mixtures, each with a total volume of 40.0 , and the highest temperature of every mixture was recorded.
| Volume of ± 0.5 / | Volume of ± 0.5 / | Highest temperature ± 1 / °C |
|---|---|---|
| 0.0 | 40.0 | 20 |
| 4.0 | 36.0 | 23 |
| 8.0 | 32.0 | 27 |
| 12.0 | 28.0 | 30 |
| 16.0 | 24.0 | 32 |
| 20.0 | 20.0 | 32 |
| 24.0 | 16.0 | 30 |
| 28.0 | 12.0 | 27 |
| 32.0 | 8.0 | 25 |
| 36.0 | 4.0 | 22 |
| 40.0 | 0.0 | 20 |
(i) Suggest one hazard to health or safety in Student A's procedure.
(ii) Student A plotted the highest temperature of each mixture against the volume of nitric acid.
With a ruler, draw two straight lines of best fit: one following the rising set of points and the other following the falling set, then extend both until they meet.
(i) nitric acid / potassium hydroxide solution is corrosive «and can burn the skin or damage the eyes» ✔
OR
the glass beaker / thermometer may break «and cut the skin» ✔
(ii) two straight lines drawn with a ruler: the rising line through «or close to» the points from 0.0 to 12.0 and the falling line through the points from 20.0 to 40.0 , both extended until they cross «at about 17 and 34 °C» ✔
(i) [1] for any specific hazard: corrosive acid or alkali (accept 'burns' or 'irritates the skin or eyes'), broken glass, hot liquid. (ii) [1] for both lines passing close to their data points, not through the point at 16.0 cm3, and extended to the intersection; accept a rising line that takes the 16.0 cm3 point into account but passes above it; lines that are not straight or are obviously drawn without a ruler score zero. On screen, accept a description of the intersection, or its coordinates (about 17 cm3 and 34 °C), in place of drawn lines.
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Policz na kartce jak na maturze, odsłoń klucz i porównaj. Potem odhacz, żeby wiedzieć, co masz już za sobą.
ZrobioneOdhaczanie zapisuje się na Twoim koncie, więc wymaga darmowego konta. Zajmuje chwilę i wracasz do tego samego zadania.