The maximum number of water molecules among the following is:

1. 18 mL of water 
2. 0.18 g of water 
3. 0.00224 L water vapours at 1 atm and 273 K
4. 10^-3 mol of water 

Calculate the mole fraction of the solute in a 1.00 m aqueous solution.

A mixture consists of hydrogen and oxygen gases in the mass ratio 1 : 4. Determine the mole ratio of hydrogen molecules to oxygen molecules present in the mixture.

The volume occupied by one water molecule (density = 1 g cm^-3) is:

1. $9.0\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

2. $6.023\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

3. $3.0\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

4. $5.5\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

The volume of oxygen gas (O₂) needed to completely burn 1 L of propane gas (C₃H₈)  (both O₂ & propane measured at 0°C and 1 atm) will be:
1. 7 L
2. 6 L
3. 5 L
4. 10 L

What is the number of moles of PbCl₂ formed when 6.5 g of PbO reacts with 3.2 g of HCl?

1. 0.044
2. 0.333
3. 0.011
4. 0.029

Concentrated aqueous sulphuric acid is 98% H₂SO₄ by mass and has a density of 1.80 g mL^-1.
The volume of acid required to make one litre of 0.1 M H₂SO₄ solution is:

What is the number of moles of O-atom in 126 amu of ${\mathrm{HNO}}_3$?

1.  2

2.  $\frac{2}{{\mathrm{N}}_{\mathrm{A}}}$

3.  6

4.  $\frac{6}{{\mathrm{N}}_{\mathrm{A}}}$