Which correctly describes the relationship between a hydrate, water, and an anhydrous compound?
heating an anhydrous compound forms water and a hydrate.
adding water to an anhydrous compound forms a hydrate.
combining an anhydrous compound and a hydrate produces water.
removing a hydrate from an anhydrous compound produces water

Adding water to an anhydrous compound forms a hydrate.

Explanation:-

Hydrates are compounds formed by compounds which contain water as molecules in their structure. Example:

Anhydrous compounds are those which do not contain molecules of water in their structure. Example:

Thus on heating hydrates lose water to form anhydrous compounds.

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles