Question

can someone help me in these attachment

Answer 1

1 - nitrogenhydrie

2- hard water

3-iron +carbon dioxied

4-Aluminiumoxide

2 and last

please like and follow

Answer 2

The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope. (Atomic mass is also referred to as atomic weight, but the term "mass" is more accurate.)