Answer:
Explanation:
The symbol M in 0.100 M means molarity.
Molarity is the unit of concentration that indicates the number of moles of solute in 1 liter of solution:
- M = moles of solute / liters of solution.
You have 0.5 liters of the solution, so you have:
- moles of solute = M × number of liters = 0.5 liters × 0.100 M = 0.05 moles.
Now to convert moles of Na₂SO₄ to mass in grams you use the molar mass of Na₂SO₄:
- molar mass of Na₂SO₄ = 142 g/mol
- molar mass = mass in grams /number of moles
- mass in grams = molar mass × number of moles = 0.05 mol × 142 g/mol = 7.1 g
Rounded to 1 significant figure: 7 g.
