1)Here is an example: CN^- (ignore the negative charge)

C is carbon. N is Nitrogen. C has an atomic mass of 12g. N has an atomic mass of 14g. Add them together to get the molar mass:

You get 26 grams of Cyanide.

2)Let's try a second, harder, example:Sr(NO₃)₂, which is Strontium(II) Nitrate.
Use divisive skill in calculating this molecular mass:

Sr has 1 atom.
N, because it is in parenthesis, has 2 atoms (the subscript outside the parenthesis multiplies the elements inside the parenthesis).
O has 3 atoms while inside the parenthesis, and is multiplied by the "2" subscript outside the parenthesis, thus giving O 6 atoms total.

Strontium's atomic mass is 87.62g. ALWAYS use the tenth's decimal, even if it is zero. You may use the hundreths and so on decimals to round up the tenths decimal. Thus Strontium's atomic mass is 87.6g. There is only one Strontium atom, so the final mass is 87.6g.
Nitrogen's mass is 14.007g; rounded up it is 14.0. There are 2 Nitrogen atoms. So: 14.0g+14.0g=28.0g. The final mass is 28.0g.
Oxygen's mass is 15.999g; rounded up, this is 16.0g. There ar 6 Oxygen atoms. So: 16.0g+16.0g+16.0g+16.0g+16.0g+16.0g=96.0g. The final mass is 96.0g.

Now add them up:

Your total is 211.6g.

Now let's try converting grams to moles. This is a hard process at first, but you'll catch on. First calculate the molecular mass.

NaCl
Na (1 atom)=1(23.1g)=23.1g
Cl (1 atom)=1(35.1g)=35.1g

Say you were given 25g NaCl. You need to find how many moles that is:

25g NaCl = 1mol NaCl = 25mol NaCl = 1.224mol NaCl
....................^{58.2g NaCl}...............^58.2

You have 1.224mol NaCl from 25g NaCl.

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