Answer:
0.1 M
Explanation:
Molarity = number of moles / litres of solution.
4 g of calcium bromide = 0.02 mol
(found by dividing 4 g by the atomic mass of CaBr2, which is 199.886)
200 mL of solution = 0.2 litres
Molarity = 0.02 mol / 0.2 L = 0.1 M
Answer:
A. Wipe down the glassware to remove any cleaning solvent.
Explanation:
· Remove stoppers and stopcocks when they are not in use. Otherwise, they may "freeze" in place. You can de-grease ground glass joints by wiping them with a lint-free towel soaked with ether or acetone. Wear gloves and avoid breathing the fumes. The deionized water rinse should form a smooth sheet when poured through clean glassware.
The molecular mass of pyrene is 204.4 g/mol.
From;
ΔT = Kb m i
Where;
- ΔT = boiling point elevation
- Kb = boiling point constant
- m = molality
- i = Van't Hoff factor
Since the compound is molecular; i = 1
The number of moles of pyrene = 4.04 g/MM
Where; MM = molar mass of pyrene
molality = number of moles of pyrene/mass of solvent in Kg
The mass of solvent = 10 g or 0.01 Kg
molality = 4.04 g/MM/0.01
ΔT = Boiling point of solution - Boiling point of pure solvent
ΔT = 85.1°C - 80.1°C
ΔT = 5°C
5 = 2.53 × 4.04 g/MM/0.01 × 1
5 = 10.22 × 1/0.01 MM
0.05MM = 10.22
MM= 10.22/0.05
MM= 204.4 g/mol
Learn more: brainly.com/question/2292439
