Chemistry 溫習題目 8

[匿名]

2015-06-15 1:11 am

1. A few drops of ammonia solution are added separately to the following metal ion solutions.
K+(aq), Mg2+(aq), Fe2+(aq), Cu2+(aq)
a) Which metal ion(s) will form coloured precipitate(s)? Name and state the colour of the precipitate(s).
b) Which metal ion(s) will form white precipitate(s)? Write ionic equation(s) for the formation of the white precipitate(s).
c) What ion in ammonia solution is responsible for the formation of the white and coloured precipitates? Write an equation for the formation of this ion in ammonia solution.
d) Suggest a common use of ammonia in daily life.

2. You are given a bottle of sulphuric acid and a bottle of hydrochloric acid of the same concentration. Describe how you would identify them by
a) physical method, and
b) chemical method.

回答 (1)

polarbearhmh

2015-06-15 1:52 am

✔ 最佳答案

1.

a) Fe²⁺(aq) and Cu²⁺(aq) ions will form dark green and pale blue precipitates respectively.

b) Mg²⁺(aq) will form white precipitate.
Mg²⁺(aq) + 2OH⁻(aq) → Mg(OH)₂ (s)

c) hydroxide ion. (or OH⁻(aq) )
NH₃(aq) + H₂O(l) ⇌ NH₄⁺(aq) + OH⁻(aq)

d)
Integrants of window cleaners.

2.

a) Measure the pH values of the two acids by pH meter. The acid with higher pH values is hydrochloric acid.

b) Add calcium to the two excess volumes of acids. Calcium dissolves completely in hydrochloric acid but does not dissolve completely in sulphuric acid (forming insoluble CaSO₄).

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