Calculate the volume of hydrogen that will be released when 20 g of calcium interacts with nitric acid.

First, we write down the equation of reactions.
Ca + 2HNO3 = Ca (NO3) 2 + H2.
Next, we find the amount of calcium substance using the following formula.
n = m / M.
M (Ca) = 40 g / mol.
n = 20 g / 40 g / mol = 0.5 mol.
Further, according to the reaction equation, we find the molar mass of hydrogen.
0.5 mol Ca – x mol H2.
1 mol of Ca – 1 mol of H2.
Find the unknown value of x.
X = 0.5 mol × 1 mol ÷ 1 mol = 0.5 mol H2.
Next, we find the volume of hydrogen.
n = V / Vm.
V = n × Vm = 0.5 mol × 22.4 L / mol = 11.2 L H2.
This means that 11.2 liters of hydrogen were released.
Answer: V (H2) = 11.2 liters.