Find the molar mass for each of the following:

Question

1. FeCrO4
2. BaCI2
3. NaC2H3O2
4. Ammonium Sulfide
5. Dinitrogen monoxide
6. How many protons does the isotope 1-129 have?
7. How many neutrons does the isotope 1-129 have?
8. How many electrons does a Ba+2 ion have?
9. What is the mass of a diamond that has a volume of 1.7 ml and a density of 1.06 g/cm3?

Answer 1

This is just doing your homework for you, so instead, I'll explain, and you do it.

To find molar mass, use a periodic table to look up the atomic mass of each element in the compound and add them up. For example:

(1) FeCrO₄

Fe = 55.9

Cr = 52.0

O = 16.0 x 4 = 64

Total = 55.9 + 52.0 + 64.0 = 171.9 g/mole

Do 2 and 3 the same way

(4) Ammonium sulfide is (NH₄)₂S. There are 2 N, 8H and 1 S. Add them up.

(5) Dinitrogen monoixide is N₂O. There are 2 N and 1 O. Add them up.

(6) An isotope only differs by the number of neutrons. Protons and electrons are the same. So, I-129 is iodine-129 and it has 53 protons and 76 neutrons (129-53).

(7) I-129 has 76 neutrons

(8) Barium has 56 protons and 56 electrons. Ba²⁺ has lost 2 electrons so has 54 electrons.

(9) Density = mass/volume so mass = density x volume = 1.06 g/ml x 1.7 ml = 1.8 ml (1 ml = 1 cm³)