7. Calculate the volume of hydrogen gas produced at s.t.p when 1.15g of sodium metal react

Question

with water. (Na=23, molar gas volume=22400cm3
) (3mks)

Answer 1

First, we need to determine the moles of sodium reacting:
1.15g / 23 g/mol = 0.05 moles of Na

The balanced chemical equation for the reaction of sodium with water is:
2Na + 2H2O -> 2NaOH + H2

From the equation, we see that 2 moles of sodium produce 1 mole of hydrogen gas.

Since 0.05 moles of Na is reacting, the amount of hydrogen gas produced will be:
0.05 moles / 2 = 0.025 moles of H2

Now, we need to convert moles of hydrogen gas to volume at STP:
1 mole of gas at STP occupies 22,400 cm3

0.025 moles * 22,400 cm3/mole = 560 cm3

Therefore, the volume of hydrogen gas produced at STP when 1.15g of sodium reacts with water is 560 cm3.