Basic Laws & Stoichiometry

The law of conservation of mass was proposed by ...

The law of definite proportions (Proust) states that ...

The number of particles in 1 mole of a substance is ...

The molar mass of $\mathrm{H}{}_2\mathrm{O}$ (Ar H = 1, O = 16) is ...

The formula relating the number of moles $(n)$, mass $(m)$, and molar mass $(M)$ is ...

If 4 g of hydrogen reacts completely with 32 g of oxygen, the mass of water formed is ...

The number of moles in 36 g of water ($M=18\text{g/mol}$) is ...

The mass of 0.5 mole of $\mathrm{CO}{}_2$ ($M=44\text{g/mol}$) is ...

The number of molecules in 0.5 mole of oxygen gas is ...

The mass ratio of hydrogen to oxygen in water is always ...

The volume of 1 mole of any gas at standard conditions (STP) is ...

The molar mass of $\mathrm{NaOH}$ (Ar Na = 23, O = 16, H = 1) is ...

The number of particles in 2 moles of a substance is ...

The mass of 0.25 mole of $\mathrm{NaCl}$ ($M=58.5\text{g/mol}$) is ...

A compound contains 40% C, 6.7% H, and 53.3% O (Ar C = 12, H = 1, O = 16). Its empirical formula is ...

4 g of calcium (Ar Ca = 40) reacts with oxygen to form $\mathrm{CaO}$. The mass of $\mathrm{CaO}$ formed is ...

The volume of 3.2 g of oxygen gas $\mathrm{O}{}_2$ (Ar O = 16) at STP is ...

If 2 moles of $\mathrm{H}{}_2$ react with 1 mole of $\mathrm{O}{}_2$ to form $\mathrm{H}{}_2\mathrm{O}$, the moles of water formed are ...

The mass percent of oxygen in $\mathrm{H}{}_2\mathrm{O}$ (Ar H = 1, O = 16) is ...

5.6 g of iron (Ar Fe = 56) reacts with excess hydrochloric acid according to $\mathrm{Fe}+2\mathrm{HCl}\to \mathrm{FeCl}{}_2+\mathrm{H}{}_2$. The volume of $\mathrm{H}{}_2$ at STP is ...