Advertisements
Advertisements
Question
Potassium nitrate on strong heating decomposes as under :
2KNO3 → 2KNO2 + O2
Calculate : Weight of oxygen formed when 5.05g of potassium nitrate decomposes completely.
(K = 39, 0 = 16, N = 14)
Advertisements
Solution
Given equation is: 2KNO3 → 2KNO2 + O2
Molecular mass of KNO3 is : (Atomic mass of K + Atomic mass of N + Atomic mass of O) = (39 + 14 + 16 x 3 ) = 101
Molecular mass of of KNO2 = (39 + 14 + 16 x 2) = 85
Now, decomposition of 101g of KNO3 yield = 16g of O2
So, decomposition of 5.05 g of KNO3 will yield = 16 x 5 .05 / 101 = 0.8 g
Hence, when 5.05g of potassium nitrate decomposes completely 0.8 g of oxygen is formed.
APPEARS IN
RELATED QUESTIONS
Aluminium carbide reacts with water according to the following equation :
`Al_4C_3 + 12H_2O-> 4Al(OH)_3 + 3CH_4`
1)What mass of aluminium hydroxide is formed from 12g of aluminium carbide?
2) What volume of methane at s.t.p. is obtained from 12g of aluminium carbide?
[Relatively molecular weight of `Al_4Cl_3 = 144; Al(OH)_3 = 78]`
Calculate the relative molecular mass of Ammonium sulphate.
(use K = 39, Cl = 35.5, O = 16, C = 12, H = 1, Na = 23, N = 14, S= 32)
Empirical formula of a compound is CH2O. If its empirical formula is equal to its vapour density, calculate the molecular formula of the compound.
Calculate the percentage of water in ferrous sulphate crystals.
[Fe = 56, S = 32, O =16, H = 1].
Concentrated nitric acid oxidizes phosphorous to phosphoric acid according to the following equation :
P + 5HNO3 → H3PO4 + H2O + 5NO2
What mass of nitric acid will be consumed at the same time?
When excess lead nitrate solution was added to a solution of sodium sulphate, 15.1g of lead sulphate was precipitated. What mass of sodium sulphate was present in the original solution?
Na2SO4 + Pb(NO3)2 → PbSO4 + 2NaNO3
(H = 1, C = 12, O = 16, Na = 23, S = 32, Pb = 207)
The reaction of potassium permanganate (VII) with acidified iron (II) sulphate is given below:
2KMno4 + 10FeSO4 + 8H2O → K2SO4 + 2MnSO4 + 5Fe2(SO4)3 + 8H2O
If 15.8g of potassium permanganate (VII) was used in the reaction, calculate the mass of iron (II) sulphate used in the above reaction.
Find the weight of 0.2 mole of H2 gas.
Correct the statement, if required.
Under similar conditions of temperature and pressure, two volumes of hydrogen combined with two volumes of oxygen will give two volumes of water vapour.
A gas cylinder filled with hydrogen holds 5 g of the gas. The same cylinder holds 85 g of gas X under the same temperature and pressure. Calculate the vapour density of gas X.
