F.3 Chem 問題 22分 明天考試用!!

1. B. (1) and (3) only

2. A. photosynthesis

3. A. cannot be decomposed easily

9. B. (1) and (3) only

10. D. sodium

14. C. (2) and (3) only

21. B. (1) and (3) only

22. A. bluish green

23. C. sulphur

25. A. chloride ions

Q1 is wrong.Answer should be B.
Reactivity is related to the ability of the formation of new substances(like a metal with a high reactivity can react with water and give metal hydroxide and hydrogen gas which are new substances.), so it is a chemical property.Heat capacity and conductivity are related to the energy needed to raise the temperature and the ability to allow the electricity, no connection to the formation of new substances so they are physical properties.
Q2 is photosynthesis(A).
In the process of photosynthesis, new substances formed(oxygen and starch),so it is a chemical change. Condensation only change the state of matter so it is a physical change.
Q3 is correct.
Q14 is correct, potassium's density is lower than water.
Q21 is correct.Only hydrogen(element) can burn with a pop sound, if you do burning splint test with steam(also contain hydrogen), will it have pop sound?
Q22 is correct, the flame colour of burning copper compounds is bluish-green.
Q23 I am not very sure>Q25 answer is A(chloride ion).If chloride ion is present, a white precipitate forms.