Question

Q2:
What is the mass, in grams, of potassium in 12.5 g of K2Cr2O7 (molar mass = 294 g/mol)? (K = 39, O = 16, Cr = 52)

Answer 1

Answer:

78g

Molar mass is the mass of 1 mole of substances in grams.

Let us first find out Molecular mass of K2Cr2O7

Atomic mass of K=39u

Atomic mass of Cr=52u

Atomic mass of O=16u

Molecular mass of K2Cr2O7 is the sum of all the atomic masses of the elements present in the compound.

=2x39+2x52+7x16

=78+104+112

=294 Unified mass.

Molar mass of K2Cr2O7 is 294g

294-216

so answer is 78g

Answer 2

Answer:

I think the answer would be 78 g