What volume of hydrogen gas at STP is produced by the complete reaction of 15.0 g of sodium according to the following equation:

2Na + 2H2O -----> 2NaOH + H2?

1 answer

The balanced equation shows that 2 moles of sodium produce 1 mole of hydrogen gas.

First, we need to calculate the number of moles of sodium in 15.0 g:

moles of Na = mass / molar mass = 15.0 g / 22.99 g/mol = 0.652 moles

Since 2 moles of Na produce 1 mole of H2, we can use stoichiometry to calculate the moles of H2 produced:

moles of H2 = moles of Na / 2 = 0.652 moles / 2 = 0.326 moles

Finally, we can use the ideal gas law to find the volume of H2 at STP (standard temperature and pressure, which is 0°C and 1 atm):

PV = nRT

where P = 1 atm, V is the volume we want to find, n = 0.326 moles, R is the gas constant (0.08206 L atm/mol K), and T = 273 K.

Solving for V:

V = (nRT) / P = (0.326 mol * 0.08206 L atm/mol K * 273 K) / 1 atm = 6.90 L

Therefore, 15.0 g of sodium at STP produces 6.90 L of hydrogen gas.