Explanation:
a) In 1 mole of methane there are 4 moles of hydrogen atom
Atomic mass of 1 mole of hydrogen atom = 1 g
Mass of hydrogen in 1 mole of methane = 4 × 1 g = 4 g
b) In 1 mole of chloroform there are 1 mole of hydrogen atom
Atomic mass of 1 mole of hydrogen atom = 1 g
Mass of hydrogen in 1 mole of methane = 1× 1 g = 1 g
c) In 1 mole of
there are 10 moles of hydrogen atom
Atomic mass of 1 mole of hydrogen atom = 1 g
Mass of hydrogen in 1 mole of
= 10 × 1 g = 10 g
d)In 1 mole of
there are 12 moles of hydrogen atom.

Atomic mass of 1 mole of hydrogen atom = 1 g
Mass of hydrogen in 1 mole of
= 12 × 1 g = 12 g
Answer:
The element will be 
Explanation:
Given that,
Number of proton = 80
Number of neutron = 81
Number of electron = 79
We know that,
The atomic number is equal to the number of proton.
So, the atomic number is 80.
According to atomic number,
The element will be mercury.
We need to calculate the atomic mass
Using formula of atomic mass

Put the value into the formula


We need to find the element
Using atomic mass and atomic number


So, the element will be

Put the value of A and Z
Hence, The element will be 
Answer:
The answer is Sodium chloride.
Na is sodium and Cl is chlorine.