Question about molecular mass?

Question

I have these for a class home work assginment and I don't know how to figure this out...

What is the molecular mass of CaCO3? Include appropriate units?



If you had 50 grams of CaCO3, how many moles of CaCO3 would you have? (Show your work and include appropriate units.)



I just need help understanding it, thank you

Answer 1

Add the molecular weight of Ca, and C, and O, that would be 40.08+12.01+ 3(16.0) and thats your molecular mass, , it can be in grams/moles
When you're finding the moles of CaCO3, you would
set the equations up and let the units drive your math.
50 Grams ofo CaCO3x 1 mole of CaCO3/the molecular mass you got earlier by adding it up. that would give you moles of 50 grams of CaCO3.
Answer should be around 0.499moles of 50 grams of CaCO2
Hope this helps


when you want to find grams, you multipy Moles with Molecular or atomic weight
When you want to find moles you divide Grams over molecular weight( what you did for this question)
and when you want to find Molecular weight you divide Grams over moles

Answer 2

Molecular mass = Ca + C + 3 x O
40 + 12 + 48 = 100 amu (or grams per mole)

50 g / 100 grams per mole = 0.5 mol CaCO3