When 10 grams of water completely evaporate into water vapor, the volume of the water vapor is greater than the volume of the original liquid water, but the mass remains the same. Why does the mass stay the same? Which answer is correct? A
The temperature of the liquid water and water vapor is the same.

The temperature of the liquid water and water vapor is the same.

B
The density of the liquid water is the same as the density of the water vapor.

The density of the liquid water is the same as the density of the water vapor.

C
The number of atoms in the water vapor is equal to the number of atoms in the liquid water.

The number of atoms in the water vapor is equal to the number of atoms in the liquid water.

D
The distance between the water molecules is the same in the liquid and the vapor.

The distance between the water molecules is the same in the liquid and the vapor.

I think the answer is B or C, its kind of hard.

they vary. it used to be meat, grain, bread, candy, beverages, donuts, and fruits/vegetables. now they added exercise in.

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.