Zadanie 1c
Wzorowane na: Chemistry HL Paper 3, November 2023, TZ1, pytanie 1(c). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Informacja do zadań 1a-1d.
A food chemistry group investigated how the processing and storage of fruit juice affects its vitamin C (ascorbic acid) content.
Polecenie
The concentration of vitamin C and the pH of five fruit juices were measured.
| Juice | Concentration of vitamin C / mg dm−3 | pH |
|---|---|---|
| Honeydew melon | 27 | 5.84 |
| Peach | 48 | 3.74 |
| Mango | 73 | 4.71 |
| Strawberry | 121 | 3.28 |
| Grapefruit | 160 | 3.52 |
Use the data to deduce whether pH and the concentration of vitamin C are correlated, giving a reason.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
yes AND the correlation coefficient is about −0.7 «a moderate negative correlation: juices with more vitamin C tend to have a lower pH» ✔
OR
yes AND pH generally falls as the concentration of vitamin C rises, with mango as the clearest exception ✔
OR
no AND mango has a middle concentration of vitamin C but the second highest pH / only five juices, with one point that does not follow the trend ✔
Schemat punktowania
[1]: either conclusion, supported by a valid reason that is based on the numbers, calculated or described. A bare 'yes' or 'no' followed only by 'negative', 'weak', 'moderate' or 'strong' correlation earns nothing. Do not accept a claim that r = −0.73 means the correlation is weak.
Komentarz
Either conclusion earns the mark when it is argued from the data; the mark is for the reason, not for the verdict.