(English Medium) ICSE Class 10 - CISCE Question Bank Solutions

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)

What weight of sulphuric acid will be required to dissolve 3g of magnesium carbonate?
[Mg = 24, C =12, 0 = 16 ]
MgCO₃ + H₂SO₄ → MgSO₄ + H₂O+ CO₂

Calculate the percentage of water in ferrous sulphate crystals.
[Fe = 56, S = 32, O =16, H = 1].

An organic compound has the following percentage composition: C = 12.76%, H = 2.13%, Br = 85.11%. The vapour density of the compound is 94. Find out its molecular formula.

10g of NaCl solution is mixed with 17g of silver nitrate solution. Calculate the weight of silver chloride precipitated.
AgNO₃ + NaCl → AgCI + NaNO₃

Find the total percentage of oxygen in magnesium nitrate crystal Mg(NO₃)₂.6H₂O.
[H = 1, N = 14, O = 16, Mg = 24]

What is the mass of nitrogen in 1000Kg of urea [CO(NH2)2] ?
[H = 1, C= 12, N= 14, O = 16]

Calculate the percentage of boron (B) in borax (Na₂B₄O₇.10H₂O). [H = 1, B = 11, O = 16, Na = 23],
answer correct to 1 decimal place.

If the relative molecular mass of A is 90, what is the molecular formula of A?

Water can split into hydrogen and oxygen under suitable conditions. The equations representing the change is:  2H₂O(I) → 2H₂ (g) + O₂(g)
Ammonia burns in oxygen and the combustion in the presence of a catalyst may be represented as:
2NH₃ (g) +2^1/2O₂ (g) → 2NO (g) + 3H₂O (I)
What mass of steam is produced when 1.5 g of nitrogen monoxide is formed?

Concentrated nitric acid oxidises phosphorus to phosphoric acid according to the following equation:

\[\ce{P + 5HNO3 -> H3PO4 + H2O + 5NO2}\]

1. What mass of phosphoric acid can be prepared from 6.2 g of phosphorus?
2. What mass of nitric acid will be consumed at the same time?
3. What will be the volume of steam at the same time measured at 760 mm Hg pressure and 373°C?
   (H = 1; N = 14; O = 16; P = 31∴ )

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?

If a crop of wheat removes 20 Kg of nitrogen per hectare of soil, what mass of the fertilizer calcium nitrate,Ca(NO₃)₂ would be required to replace nitrogen in 10 hectare field? (N = 14, O = 16, Ca = 40)

Washing soda has the formula Na₂CO₃.10H₂O.What is the mass of anhydrous sodium carbonate left when all the water of crystallization is expelled by heating 57.2 g of washing soda?

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)

Chlorine, nitrogen, ammonia and sulphur dioxide gases are collected under the same conditions of temperature and pressure.
Copy the following table which gives the volumes of the gases collected, and the number of molecules (X) in 20L of nitrogen.You are to complete the table by giving the number of molecules in th e other gases, in terms of X.

Mention the term defined by the following sentence:
The mass of a given volume of gas compared to the mass of an equal volume of hydrogen.

Calculate the percentage of phosphorous in the fertilizer superphosphate, Ca(H₂PO₄)₂. [Ca = 40, H =1, P =31, O = 16] (Correct to 1 decimal place)

A metal M, forms a volatile chloride containing 65.5% Chlorine. If the density of the chloride relative to hydrogen is 162.5, find the molecular formula of the chloride. [M = 56, Cl = 35.5]

Samples of the gases O₂, N₂, CO₂ and CO under the same conditions of temperature and pressure contain the same number of molecules represented by X. The molecules of Oxygen, occupy V litres and have a mass of 8 g. Under the same conditions of temperature and pressure :
What is the mass of CO₂ in g?