How many moles of Ca(ClO2)2 are present in a 80.0-g sample?

Question

Can someone show the math? I want to understand how to get the answer.

Answer 1

To find out how many moles of Ca(ClO₂)₂ you have, first you have to calculate the compound's molar mass:

1 atom of Ca + 2 atoms of Cl + 4 atoms of O =

1(40g) + 2(35.5g) + 4(16.0g) = 175 g/mol (This means one mole of the compound weighs 175 grams).

After finding the molar mass of the compound, you must apply it to the mass you're given in the problem to convert from grams to moles:

80.0g of Ca(ClO₂)₂ X [1 mol of Ca(ClO₂)₂ / 175 grams]

The unit of grams cancel out, and you're left with an answer in moles: 0.457 moles

So, about 0.457 moles of Ca(ClO₂)₂ are present in an 80.0 gram sample.