Monday, November 16, 2009

Calculating moles and mass?

1Calculate the number of moles in 58.2 g of Se. SIG. FIG.

2Calculate the number of moles in 1.43x1022 NO2 molecules. SIG. FIG.

3Calculate the mass (in g) of 6.16 moles of H2O. SIG. FIG.

4Calculate the number of moles in 86.2 g SO3. SIG. FIG.

5Calculate the number of oxygen atoms in 20.6 g SO3. SIG. FIG.

I normally wouldn’t ask someone to do hw for me but right now I have no other choice since I need the time to study math If you help me fine ill give you five stars.

Calculating moles and mass?
number of avogadro is Na=6.02 * 10^23

moles= mass/MW

once you have the moles the number of atoms are

n. atoms = Na * moles

MW are easily calculable if you have a periodic table of the elements.

if not go here:

in total, you can finish this exercise in less than 2 minutes. Probably it took more to you to recheck what you have written in order to give data without mistakes. (so that we could solve your hw correctly)
Reply:Moles of H2 = 1.89*2/18

Moles of N2 = 2.18*0.235/(28*1.23)

Just subtract for the rest.

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