To produce 20 moles of ammonia via Haber's process, how many moles of hydrogen molecules are required?

1.	40 mol	2.	10 mol
3.	20 mol	4.	30 mol

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

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

10 g of hydrogen and 64 of oxygen were filled in a steel vessel and exploded. The amount of water produced in this reaction will be:

1. 2 mol

2. 3 mol

3. 4 mol

4. 1 mol

Mole fraction of solute in a 1.00 molal aqueous solution is:
1.  0.0177
2.  0.0344
3.  1.770
4.  0.1770

When \(1.0\text{ g}\) of magnesium (\(\text{Mg}\)) is reacted with \(0.56\text{ g}\) of oxygen (\(\text{O}_2\)) in a closed container, determine the reactant left in excess and calculate the mass of the excess reactant remaining after the reaction is complete: (At. wt. Mg = 24; O = 16)