Class 11 Chemistry Chapter 1 Exercise Questions & Answers (NCERT)

(i) H₂O = 18 u

(ii) CO₂ = 44 u

(iii) CH₄ = 16 u

Molar mass of Na₂SO₄ = 142 g

% Na = 32.4%

% S = 22.5%

% O = 45.1%

Empirical formula = Fe₂O₃

(i) 44 g CO₂

(ii) 22 g CO₂

(iii) 22 g CO₂

Required mass = 15.4 g

Concentration = 15.4 mol L⁻¹

Copper obtained = 39.8 g

Molecular formula = Fe₂O₃

Kilogram (kg)

All the certain digits plus the last uncertain digit in a measured quantity.

Copper obtained = 39.8 g

Average atomic mass of chlorine = 35.5 u

Carbon atoms = 6 mol

Hydrogen atoms = 18 mol

Number of molecules = 1.806 × 10²⁴

Concentration of sugar = 0.029 mol L⁻¹

Volume of methanol required = 0.025 L

SI unit of pressure = Pascal (Pa)

Pressure exerted by air = 1.01 × 10⁵ Pa

Kilogram (kg)

Kilogram (kg)

All the certain digits plus the last uncertain digit present in a measured quantity.

Mole (mol)

Pressure = Force / Area

Newton (N)

Metre (m)

Kelvin (K)

Precision refers to the closeness of repeated measurements to each other.

Accuracy refers to the closeness of a measured value to the true value.

If the digit to be dropped is less than 5, it is ignored; if it is more than 5, the preceding digit is increased by one.

4 significant figures

4 significant figures

4 significant figures

3 significant figures

Dimensional analysis is the method of converting one unit into another using conversion factors.

A given compound always contains the same elements combined in the same fixed ratio by mass.

Mass is neither created nor destroyed in a chemical reaction.