Magnesium and hydrochloric acid react to form magnesium chloride and hydrogen gas. Calculate the volume of H2 (g) produced at rtp when 4.8g Mg reacts with HCl. (Mg=24)
First, Karishma, you have to write out the balanced equation.
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
So 1 mole of Mg will produce 1 mole of H2. Since Mg has a molar mass of 24g,
4.8g x (1 mole/24g) = 0.20 mole Mg
So 0.20 mole of H2 are produced. At STP, 1 mole of any gas occupies 22.4 liters, so
0.20 mole x (22.4 liters/1 mole)
And you produce 4.48 liters of H2. (4.5 liters using significant digits)