1. The fomula for hydrated iron(II) sulphate is FeSO4 . xH2O. On strong heating, 20.1 g of the sulphate produces 9.1 g of water. What is the value of x?
2. Metal X forms an oxide. 27.53g of this oxide contains 24.96g of X. What is the mole ratio of X to oxygen in the oxide?
3.For each of the following experiments, state 1 observable change and write a chemical equation for the reation involved.
(a)Dilute nitric acid is added to magnesium carbonate powder in a beaker.
(b)A small piece of calcium is placed in a Bunsen flame.
(c)A mixture of copper(II)oxide and carbon powder is heated in a test tube.
4. There is a can of fruit juice. The body of the can is made of iron coated with another metal. The top of the can and the ring-pull are made of aluminium. Suggest why it is not advisable to buy cans of fruit juice.
Chemistry
2010-07-27 7:11 am
回答 (1)
2010-07-27 8:23 am
✔ 最佳答案
1. Molar mass of FeSO4 = 55.8 + 32.1 + 16x4 = 151.9 g/mol
Molar mass of H2O = 1x2 + 16 = 18 g/mol
Mole ratio FeSO4 : H2O
= (20.1 - 9.1)/151.9 : 9.1/18
= 0.0724 : 0.506
= 1 : 7
Hence, x = 7
2.
There is insufficient information.
More information (e.g. the relative atomic mass of X) are needed.
3.
(a)
Colourless gas bubbles are formed.
MgCO3(s) + 2HNO3(aq) → Mg(NO3)2(aq) + H2O(l) + CO2(g)
(b)
Calcium burns with a brick red flame. / A white solid is obtained.
2Ca(s) + O2(g) → 2CaO(s)
(c)
A reddish brown solid is obtained.
2CuO(s) + C(s) → 2Cu(s) + CO2(g)
4.
Fruit juice is acidic, which would react with aluminium to form toxic aluminium ions.
參考: andrew
收錄日期: 2021-04-13 17:23:42
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