Question

Student was identifying the formula of 1 mole of unknown powder. When it was placed on a scale, it was reading 399.91 g/mol. Which of

the following compounds can it be?
A AI(NO3)3
B. C3H8
C. Fe2(SO4)3
D. CaCl2

Answer 1

Answer: The compound is
`Fe_2(SO_4)_3`

Step-by-step explanation:

Molar mass is defined as the mass in grams of 1 mole of a substance.

S.I Unit of Molar mass is gram per mole and it is represented as g/mol.

A. 1 mole of
`Al(NO_3)_3` weighs = 26.98(1)+14.01(3)+15.99(9) =212.99 g/mol

B. 1 mole of
`C_3H_8` weighs = 12.01(3)+1.007(8) = 44.1 g/mol

C. 1 mole of
`Fe_2(SO_4)_3` weighs = 55.84(2)+32.06(3)+15.99(12) = 399.91 g/mol

D. 1 mole of
`CaCl_2` weighs = 40.07(1)+35.5(2)= 110.98 g/mol

Thus the compound is
`Fe_2(SO_4)_3`