How do you do Mole conversions?

Mole Conversions Please Help...?

• We have a test tomorrow and I really need help with mole conversions. here are some examples of whats to come on the test... 1. calculate the number of moles present in 6.0 x 10^25 atoms of neon. 2. determine the mass of 0.100 mol of cream of tartar (KHC4H4O6) 3. How many carbon atoms are in 45 g H2C2O4 4. What is the mass of 3.0 x 10^25 molecules of water. This was all on the study guide. Please help me out...

• Answer:

  I'm afraid this is probably too late to help you with the test, but in part 1, you are talking about 100 moles of neon. So it'll be 100 times the mass of one mole, which is 100 times the Ar (relative atomic mass) of neon, which you can look up on the periodic table. In part 2, you need to add up the atomic masses of the atoms in the formula, to get the formula mass of cream of tartar. That will give you the mass (in grams) of one mole. Multiply your answer by 0.1 to find the mass of 0.1 moles. In part 3;work out the mass of 1 mole of the compound given then work out how many moles are in 45 grams. each mole will contain 6 x 10^23 molecules, and each molecule contains two carbon atoms. Finally, in part 4, you are given 5 moles of water. so multiply Avogadro's number by 5, and that'll be the number of molecules. If you're going to be good at chemistry, you have to pay some homage to Avogadro, and appreciate how useful his number is.