Question

A sample of zinc metal reacts completely with an excess of hydrochloric acid:

Zn (s) + 2HCl (aq) ---> ZnCl₂ (aq) + H₂ (g)

The hydrogen gas produced is collected over water at 25.0°C. The volume of the gas is 7.80 L and the pressure is 0.980 atm. Calculate the amount of zinc metal in grams consumed in the reaction.

Answer 1

The amount of zinc metal consumed in the reaction is 19.5 grams.

Step-by-step explanation:

To calculate the amount of zinc metal consumed in the reaction, we need to use stoichiometry to relate the volume of hydrogen gas produced to the moles of zinc metal consumed. First, we calculate the moles of hydrogen gas using the ideal gas law equation:

n = PV / RT

where n is the number of moles, P is the pressure, V is the volume, R is the ideal gas constant (0.0821 L·atm/mol·K), and T is the temperature in Kelvin. So, we convert the temperature from Celsius to Kelvin by adding 273.15:

T = 25.0 + 273.15 = 298.15 K

Substituting the values into the equation:

n = (0.980 atm) * (7.80 L) / (0.0821 L·atm/mol·K * 298.15 K) = 0.298 mol

According to the balanced chemical equation, 1 mole of zinc metal reacts with 1 mole of hydrogen gas. Therefore, the amount of zinc metal consumed in the reaction is also 0.298 mol. Finally, we can calculate the mass of the zinc metal using its molar mass:

Mass = moles * molar mass = 0.298 mol * 65.38 g/mol = 19.5 g