Answer:
2.79 °C/m
Explanation:
When a nonvolatile solute is dissolved in a pure solvent, the boiling point of the solvent increases. This property is called ebullioscopy. The temperature change (ΔT) can be calculated by:
ΔT = Kb*W*i
Where Kb is the ebullioscopy constant for the solvent, W is the molality and i is the van't Hoff factor.
W = m1/(M1*m2)
Where m1 is the mass of the solute (in g), M1 is the molar mass of the solute, and m2 is the mass of the solvent (in kg).
The van't Hoff factor represents the dissociation of the elements. For an organic molecule, we can approximate i = 1. Thus:
m1 = 2.00 g
M1 = 147 g/mol
m2 = 0.0225 kg
W = 2/(147*0.0225)
W = 0.6047 mol/kg
(82.39 - 80.70) = Kb*0.6047*1
0.6047Kb = 1.69
Kb = 2.79 °C/m
Answer:
B.
Explanation:
Propanal is an organic compound with the formula CH3CH2CHO. Aldehyde is colorless, flammable and a slightly fruity odor.
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Answer: The mass of the sample is 1264.800 kg.
Explanation:
Mass of the piece of copper = m
Volume of the copper price = 
m = 1,264,800 g = 1,264.800 kg (1 kg = 1000 g)
The mass of the sample is 1264.800 kg.
Answer:
24 moles of oxygen are required.
Explanation:
Given data:
Number of moles of CuFeS = 12 mol
Number of moles of O₂ react = ?
Solution:
Chemical equation:
2CuFeS + 4O₂ → Cu₂S + 3SO₂ + 2FeO
now we will compare the moles of O₂ and CuFeS.
CuFeS : O₂
2 : 4
12 : 4/2×12 = 24 mol
