Some Basic Concepts of Chemistry

Which of the following represents a chemical equation balanced according to the law of conservation of mass?

1. H2 + O2 → H2O
2. 2H2 + O2 → 2H2O
3. H2 + O2 → H2O2
4. H2 + O → H2O

The amount of substance present in 18 g of water is:

1. 1 mole
2. 2 moles
3. 18 moles
4. 0.5 mole

The law of multiple proportions was given by:

1. Dalton
2. Lavoisier
3. Rutherford
4. Bohr

The SI unit of mass is:

1. Gram
2. Kilogram
3. Milligram
4. Tonne

Which of the following is a limiting reagent?

1. Substance present in excess
2. Substance completely consumed first
3. Catalyst
4. Solvent

One mole of oxygen gas contains:

1. 6.022 × 10^23 oxygen molecules
2. 3.011 × 10^23 molecules
3. 1 molecule
4. 16 molecules

The formula used to calculate molarity is:

1. M = moles of solute / volume of solution in litres
2. M = mass × volume
3. M = volume / mass
4. M = mass / density

The molar mass of carbon dioxide (CO2) is:

1. 28 g/mol
2. 32 g/mol
3. 44 g/mol
4. 18 g/mol

The number of significant figures in 0.00520 is:

1. 2
2. 3
3. 4
4. 5

The law of conservation of mass was proposed by:

1. Dalton
2. Lavoisier
3. Avogadro
4. Boyle

The molecular formula of water is:

1. HO
2. H2O
3. H2O2
4. OH22

The empirical formula represents:

1. Actual number of atoms in a molecule
2. Simplest whole number ratio of atoms
3. Molecular mass of a compound
4. Physical state of a compound

The mass of one mole of carbon atoms is:

1. 6 g
2. 12 g
3. 18 g
4. 24 g

The number of particles present in one mole of any substance is:

1. 6.022 × 10^23
2. 3.011 × 10^23
3. 1.0 × 10^23
4. 9.8 × 10^23

The SI unit of amount of substance is:

1. Gram
2. Mole
3. Kilogram
4. Litre