Answer:
The mass percentage of the solution is 10.46%.
The molality of the solution is 2.5403 mol/kg.
Explanation:
A bottle of wine contains 12.9% ethanol by volume.
This means that in 100 mL of solution 12.9 L of alcohol is present.
Volume of alcohol = v = 12.9 L
Mass of the ethanol = m
Density of the ethanol ,d= 
Mass of water = M
Volume of water ,V= 100 mL - 12.9 mL = 87.1 mL
Density of water = D=1.00 g/mL
Mass percent
Molality :
M = 87.1 g = 0.0871 kg (1 kg =1000 g)
B and C are the correct answers
Answer:
2.73%
Explanation:
Molarity of NaOH = 0.75 M
Density of solution = 1.1 g/mL
Mass percent of NaOH = ?
Solution:
Number of moles of NaOH = 0.75 mol from 0.75 mol/L
Mass of NaOH = number of moles × molar mass
Mass of NaOH = 0.75 mol × 40 g/mol
Mass of NaOH = 30 g
Mass of solution:
d = m/v
1.1 g/ mL = m/ 1000 mL
m = 1100 g
Percentage of NaOH:
% NaOH = mass of solute / mass of solution × 100
% NaOH = 30 g/ 1100 g × 100
% NaOH = 2.73%
Answer:
1.20 M
Explanation:
Convert grams of Na₂CO₃ to moles. (50.84 g)/(105.99 g/mol) = 0.4797 mol
Molarity is (moles of solute)/(liters of solvent) = (0.4797 mol)/(0.400 L) = 1.20 M
