In a #0.698*mol# quantity of sodium carbonate, what is the mass of material?

By definition, #"moles"="mass of stuff"/"molar mass of stuff"#

And thus #"mass of stuff"="moles of stuff"xx"molar mass of stuff"#

And here, this product gives.......

#"Mass"=0.698*cancel(mol)xx105.99*g*cancel(mol^-1)=??*g#....

How many moles of sodium ion does this mass represent?

To start, let's define a few terms.

1 mole of anything is equal to #6.022times10^23# of that thing.

The molar mass of a compound is the mass of one mole of that compound.

Therefore, #x# moles of something will have mass equal to #xtimes# its molar mass.

We need to know the molar mass of Sodium Carbonate to continue.

Each mole will have 2 moles of sodium, 1 mole of carbon, and 3 moles of oxygen.

Conveniently, the periodic table will tell us the molar masses of all the elements in Sodium Carbonate.

The molar mass of Na is 23.0g, the molar mass of carbon is 12.0g, and the molar mass of oxygen is 16.0g.

Therefore, #2times23.0g+1times12.0g+3times16.0g=106.0g/mol#

Now, we know how massive one mole of Sodium Carbonate is. To get how much #0.698# moles are, all we have to do is multiply by #0.698#.

#106.0g/mol times0.698mol=74.0g#