# chem

posted by
**Annette**
.

Will someone help me with this problem, please?

Calculate the mass in grams of 1.20*10^24 molecules of CO2.

Well, convert it to moles of CO2.

number moles= 1.2*10^{24}/avagnumber

Now, you take the molecular mass of CO2 (12 + 2*16) and multiply that by the number of moles.

I got 8.772717608E47

is that the answer?

No.

the number of moles is 2. 2(44)= xxx grams.

Okay, sorry for not showing my work. So I did 1.2*10^24/6.02*10^23 and got 1.99 (2). So now I multipy 2 times the molecular mass of CO2, which is 44. The answer is 88. 88 grams?

Yes, I got the same answer the first time:8.772717608E47

For my calculator, 8.772717608E47 =88, for some reason. For another problem, the answer was 68.71g and my calculator read 6.871096346E47.