What mass of lithium (in g) is required to react completely with 58.3 mL of N2 gas at STP?
To determine the mass of lithium required to react completely with a given volume of N2 gas at STP, we need to use the balanced chemical equation and the molar volume of a gas at STP.
1. Write the balanced chemical equation for the reaction between lithium (Li) and nitrogen gas (N2):
2Li + N2 -> 2Li3N
2. Determine the molar volume of a gas at STP (Standard Temperature and Pressure):
The molar volume of a gas at STP is approximately 22.4 L/mol.
3. Convert the given volume of N2 gas from mL to L:
58.3 mL = 58.3/1000 L = 0.0583 L
4. Use the stoichiometry of the balanced equation to find the number of moles of N2 gas:
According to the balanced equation, 2 moles of Li react with 1 mole of N2 gas.
So, the number of moles of N2 gas = 0.0583 L × (1 mole N2/22.4 L) = 0.00260 moles N2
5. Convert the number of moles of N2 gas to moles of Li:
According to the balanced equation, it takes 2 moles of Li to react with 1 mole of N2.
So, the number of moles of Li required = 2 × 0.00260 moles N2 = 0.00520 moles Li
6. Determine the molar mass of lithium (Li) from the periodic table:
The molar mass of lithium (Li) is approximately 6.94 g/mol.
7. Calculate the mass of lithium required:
Mass of Li = Number of moles of Li × Molar mass of Li
Mass of Li = 0.00520 moles × 6.94 g/mol = 0.0360 g (rounded to four decimal places)
Therefore, approximately 0.0360 grams of lithium is required to react completely with 58.3 mL of N2 gas at STP.
2Li + 3N2 ==> 2Li3N
mol N2 gas at STP = 58.3/22,400 = ? since 1 mol of a gas at STP occupies 22.4 L.
Convert mols N2 to mols Li using the coefficients in the balanced equation.
Then convert mols Li to g Li. g = mols x atomic mass.