1.22 mg is the same as .022 grams. One gram equals 1000 mg. Convert mg to grams by dividing mg by 1000mg/gm. Volume = mass over density. Volume equals .022 grams over .754 grams/cm3 which equals .029 or .03cm3. 2.weight in kg times gravity constant. Weight in newtons equals 10kg times 9.8m/s2 that equals 98 newtons.