Question

How many grams of oxygen and hydrogen gas contains the same number of molecules as 200 kilogram of calcium carbonate?

Answer 1

First, we need to find the mole of CaCO3 because it is the key to everywhere. ( Don't forget to change the measurement from kg to g)

- n of CaCO3= gram of CaCO3 / Mr of CaCO3

n of CaCO3 = 200,000/100 (Note: 100 it's from, Ca=40, C=12, O=16)

n of CaCO3= 2000

Second, this step can repeat it twice because we want to find the grams of oxygen and hydrogen which are with the same formula as above, however, only the Mr is different because O=16 and H=1.

- n of O2 = gram of O2 / Mr of O2

2000= gram of O2/ 32

gram of O2= 64,000 grams

- n of H2= gram of H2/ Mr of H2

2000= gram of H2/ 2

grams of H2= 4,000 grams

NOTE: Remember, all the gas molecules times by 2 because the atoms are covalent bonds.