ICSE CLASS 10 CHEMISTRY PRACTICE PAPER 19

ICSE Class 10 - PRACTICE PAPER 19

PERCENTAGE COMPOSITION

(at.wt. H-1, C-12, N-14, O-16, Na-23, Mg-24, P-31, S-32, Cl-35.5, K-39, Ca-40, Cr-52, Fe-56, Cu-64, Zn-65, Br-80, Pb-207)

1.      A compound is found to contain 23.3% magnesium, 30.7% sulfur and 46.0% oxygen. What is the empirical formula of this compound?

2.      Find the empirical formula and molecular formula a compound containing 38.8% carbon, 16.2% hydrogen and 45.1% nitrogen? V.D of the compound =31.

3.      A has the empirical formula X₂Y. If the atomic weights of X and Y are 10 and 5 respectively and vapour density of the compound is 25 then find its molecular formula.

4.      A metal M forms a volatile chloride containing 65.5% of Chlorine. If the density of that chloride relative to Hydrogen is 162.5 (i.e. V.D) then find its empirical formula and molecular formula.

5.      Find the percentage of i) water and ii) Oxygen in hydrated Copper sulphate.

6.      If  30g of a Hydrocarbon has 24g of Carbon combined with Hydrogen then find its empirical formula and molecular formula.

7.      A gaseous compound of Nitrogen and Hydrogen contains 12.5% of Hydrogen by mass. Find the molecular formula of the compound if its relative molecular mass (Molecular wt.) is 32.

Problems on Mole concept and Percentage composition

Problems on Mole concept and Percentage composition

    a) Calculate:

i) The mass of 1 mole of Ammonia gas.

ii) The mass of 0.25 moles of Oxygen gas.

iii) The number of moles present in 1000g. of CaCO₃.

iv) The number of moles present in 3.6g. of Water.

v) The volume occupied by 4.4g of Carbon dioxide

b)      i)Calculate the percentage of water in Hydrated Copper sulphate.(CuSO₄.5H₂O)

(H-1, O-16, S-32, Cu-64)

ii) Determine the molecular formula of a compound having percentage composition

C-40%, O-53.3% and H-6.7% and molecular weight is 60.(C-12, O-16, H-1).