Chemistry
posted by Casey on .
Last one I promise! Thankyou for bearing with me. This seems simple enough, but chemistry genuinely makes me feel retarded so I appreciate reassurance.
How many molecules of CH4 are there in 48.2g of the compound?
I'm assuming that I should just divide 48.2 g by the molar mass of CH4 which is 16.05g, and it calculates to 3 mols. Is this correct?

If the question asked for moles, ok but it asked for molecules.
There are 6.022 x 10^23 molecules in a mole so 3.01 x 6.022 x 10^23 = # molecules. I would use 3.01 and not 3 since you have 3 significant figures in 48.2 and 4 in 16.05. 
Thankyou very much for clearing that up.

The density of mercury is 13.54 g/cm3. Suppose you need 40 gm of mercury for an experiment. What volume of mercury do you need?