Determine the volume of hydrogen gas formed when excess zinc metal is added to 100cm³ of one molar hydrochloric acid(1 mol of gas occupied 24.0 litres at room temp and pressure)
The balanced chemical equation for the reaction between zinc and hydrochloric acid is:
Zn + 2HCl -> ZnCl2 + H2
From the equation, we can see that for every mole of zinc used, one mole of hydrogen gas is produced.
Given that the volume of hydrochloric acid is 100 cm³ (which is equal to 0.1 liters) and its molarity is 1M, we can calculate the number of moles of hydrochloric acid:
Moles of HCl = volume (in liters) x molarity
= 0.1 L x 1 mol/L
= 0.1 mol
Since the reaction between zinc and hydrochloric acid is in a 1:1 ratio, the number of moles of hydrogen gas produced is also 0.1 mol.
By using the volume-mole relationship given (1 mol of gas occupies 24 liters), we can calculate the volume of hydrogen gas generated:
Volume of hydrogen gas = number of moles x 24 L/mol
= 0.1 mol x 24 L/mol
= 2.4 L
Therefore, the volume of hydrogen gas formed when excess zinc metal is added to 100 cm³ of 1M hydrochloric acid is 2.4 liters.