Answer:
212 g Na₂CO₃
Step-by-step explanation:
We are given;
- Volume of Na₂CO₃ solution as 500 mL
- Molarity of Na₂CO₃ solution as 4.00 M
We are required to calculate the mass of Na₂CO₃.
We need to know how molarity is calculated.
- Molarity is the concentration of a solution in moles per liter.
- Molarity = Number of moles of solute ÷ Volume of the solution
Step 1: we calculate the number of moles of Na₂CO₃
Moles = Molarity × Volume
Therefore;
Moles of Na₂CO₃ = 4.00 M × 0.5 L
= 2 moles
Thus, moles of Na₂CO₃ is 2 moles
Step 2: Calculate the mass of Na₂CO₃
We need to know the relationship between the mass of a compound, molar mass and the number of moles.
Moles = Mass ÷ molar mass
Rearranging the formula;
Mass = Moles × molar mass
Molar mass of Na₂CO₃ is 106 g/mol
Therefore;
Mass of Na₂CO₃ = 2 moles × 106 g/mol
= 212 g
Therefore, the mass of Na₂CO₃ that would be needed is 212 g