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

Give the empirical formula of CH₃COOH

Give example of compound whose:
Empirical formula is the same as the molecular formula.

Give example of compound whose:
Empirical formula is different from the molecular formula.

A compound of lead has following percentage composition, Pb = 90.66%, O = 9.34%. Calculate empirical formula of a compound. [Pb = 207, O = 16]

A compound contains 87.5% by mass of nitrogen and 12.5% by mass of hydrogen. Determine the empirical formula of this compound.

Calculate the empirical formula of the compound having 37.6% sodium, 23.1% silicon and 39.3% oxygen.(Answer correct to two decimal places) (O = 16, Na = 23, Si = 28)

The empirical formula of a compound is C₂H₅. Its vapour density is 29. Determine the relative molecular mass of the compound and hence its molecular formula.

The compound A has the following percentage composition by mass: C =26.7%, O = 71.1%, H = 2.2%.
Determine the empirical formula of A.(Answer to one decimal place)  (H=1,C=12,O=16)

Water can split into hydrogen and oxygen under suitable conditions. The equations representing the change is:  2H₂O(I) → 2H₂ (g) + O₂(g)
If a given experiment results in 2500cm³ of hydrogen being produced, what volume of oxygen is liberated at the same time under the same conditions of temperature and pressure?

Determine the empirical formula of the compound whose composition by mass is 42% nitrogen, 48% oxygen and 9% hydrogen.[N=14,O=16,H=1]

When gases react their volumes bear a simple ratio to each other, under the same conditions of temperature and pressure. Who proposed this gas law?

What volume of oxygen would be required for complete combustion of 100L of ethane according to the following equation?
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

The reaction 4N₂O + CH₄ → CO₂ + 2H₂O + 4N₂ takes place in the gaseous state. If the volumes of all the gases are measured at the same temperature, and pressure, calculate the volume of dinitrogen oxide (N₂O), required to give 150cm³ of steam.

The percentage composition of sodium phosphate, as determined by analysis is : 42.1% Na, 18.9% P, 39% of O. Find the empirical formula of the compound.
[H =1, N =14, Na = 23, P = 31, Cl = 35.5, Pt = 195]

Determine the empirical formula of a compound containing 47.9‰ K, 5.5‰ beryllium and 46.6‰ fluorine by mass.

A compound 'X' consists of 4.8% of C and 95.2% of Br by mass.
Determine the empirical formula of this compound.
[C = 12, Br = 80]

Calcium carbide is used for the artificial ripening of fruits. Actually the fruit ripens because of the heat evolved while calcium carbide reacts with the moisture. During this reaction calcium hydroxide and acetylene gas are formed. If 200 cm³ of acetylene is formed from a certain mass of calcium carbide, find the volume of oxygen required and carbon dioxide formed during the complete combustion. The combustion reaction can be represented as below.

\[\ce{2C2H2_{(g)} + 5O2_{(g)}-> 4CO2_{(g)} + 2H2O_{(g)}}\]

Calculate the percentage of water of crystallization in CuSO_4. 5H₂O
(H = 1, O = 16, S = 32, Cu = 64)

A compound of X and Y has the empirical formula XY₂. Its vapour density is equal to its empirical formula weight. Determine its molecular formula.

Propane burns in air according to the following equation:

\[\ce{C3H8 + 5O2 -> 3CO2 + 4H2O}\]

What volume of propane is consumed on using 1000 cm³ of air, considering only 20% of air contains oxygen?