the molar mass is how many grams it takes to make a full mole. The number in carbon 12 tells us that it takes 12 g to makes a mole, so one half of that would be <u><em>option d, 0.5</em></u>.
Density = mass/volume
density = 81 grams/0.9 cubic centimetersdensity = 90 grams per cubic centimeter
The density of the sample is 90 grams per cubic centimeter.
3.) Charge on one molecule of PO4 is -3. So on two molecule it'll be 2(-3) = -6. Let oxidation number of Pb be x. Therefore, 3x+(-6) = 0. 3x=6. x=2.
