I believe that it is petroleum ether.
Answer: The kilograms of water must evaporate from 8kg of a 25% salt solution to produce 40% salt solution is 3 kg.
Explanation:
According to the ratio and proportion:

where,
= concentration of ist solution = 25%
= mass of ist solution = 8 kg
= concentration of second solution = 40%
= mass of second solution = ? kg


Thus the final solution must have a mass of 5 kg , i.e (8-5)= 3 kg of mass must be evaporated.
Therefore, the mass that must be evaporated from 8kg of a 25% salt solution to produce 40% salt solution is 3 kg.
D. CuCl2 copper(2)chloride
Answer:
1) The vapor density of the organic compound is approximately 12.57
2) The relative molar mass (RMM) of the organic compound is approximately 25.14 grams
Explanation:
1) The mass of the balloon filled with dry hydrogen = 35 grams
The mass of the balloon filled with vapor of an organic compound = 440 grams
The vapor density = (Weight of a given volume of gas)/(Weight of equal volume of hydrogen)
The vapor density of the organic compound = (440)/(35) ≈ 12.57
The vapor density of the organic compound ≈ 12.57
2) The relative molar mass (RMM) = 2 × vapor density
The relative molar mass (RMM) of the organic compound = 2 × vapor density of the organic compound
The relative molar mass (RMM) of the organic compound ≈ 2 × 12.57 ≈ 25.14 grams
The relative molar mass (RMM) of the organic compound ≈ 25.14 grams
When the substance is creating gases. Sometimes when it’s bubbling up