Question

Consider the compound Cu(NO3)2 and answer the following questions.

Answer 1

The answer is 187.5 g of Cu (NO3)2.

First you must multiply the element's atomic mass by the amount of atoms within that compound.
-Here there is only one Cu atom, so you leave it's mass at 63.5g. (63.5g × 1)
-There are two molecules of NO3, so you multiply the atomic mass of Nitrogen (mass is 14.0g) by 2. (14.0g × 2)
-The case is not the same for Oxygen (O) because there are three oxygen atoms in the molecule of NO3,and there are two NO3. So you multiply Oxygen's atomic mass by 3 and by 2 (16.0g × 3 × 2)

Finally, you add the totals togther and get its molar mass.

Answer 2

1) Name: copper(II) nitrate

2) molar mass:

Determine the mass of every element by multiplying its subscript by the atomic mass and add the masses of all the elements

Element    atomic mass    subscript    total mass of the element
Cu            63.55              1                  63.55
N              14.01              2                  2*14.01 = 28.02
O              16.00            3*2=6            6*16.00 = 96.00

Molar mass = 63.55 + 28.02 + 96.00 = 187.57 g/mol