Atomic mass of hydrogen=1u
Atomic mass of oxygen=16u
H2o=2×1+1×16 =18u

To calculate the molecular mass of H2O, we need to consider the atomic masses of hydrogen (H) and oxygen (O). The atomic mass of hydrogen is approximately 1 gram/mol, and the atomic mass of oxygen is approximately 16 grams/mol.

Since there are two hydrogen atoms and one oxygen atom in water, we can calculate the molecular mass as follows:
2 * (atomic mass of hydrogen) + 1 * (atomic mass of oxygen)
= 2 * 1 + 1 * 16
= 2 + 16
= 18 grams/mol

Therefore, the molecular mass of H2O (water) is 18 grams/mol.


To calculate the molecular mass of NaOH, we need to consider the atomic masses of sodium (Na), oxygen (O), and hydrogen (H). The atomic mass of sodium is approximately 23 grams/mol, the atomic mass of oxygen is approximately 16 grams/mol, and the atomic mass of hydrogen is approximately 1 gram/mol.

Since there is one sodium atom, one oxygen atom, and one hydrogen atom in NaOH, we can calculate the molecular mass as follows:
1 * (atomic mass of sodium) + 1 * (atomic mass of oxygen) + 1 * (atomic mass of hydrogen)
= 1 * 23 + 1 * 16 + 1 * 1
= 23 + 16 + 1
= 40 grams/mol

Therefore, the molecular mass of NaOH (sodium hydroxide) is 40 grams/mol.


To calculate the molecular mass of MgCl2, we need to consider the atomic masses of magnesium (Mg) and chlorine (Cl). The atomic mass of magnesium is approximately 24 grams/mol, and the atomic mass of chlorine is approximately 35.5 grams/mol.

Since there is one magnesium atom and two chlorine atoms in MgCl2, we can calculate the molecular mass as follows:
1 * (atomic mass of magnesium) + 2 * (atomic mass of chlorine)
= 1 * 24 + 2 * 35.5
= 24 + 71
= 95 grams/mol

Therefore, the molecular mass of MgCl2 (magnesium chloride) is 95 grams/mol.

In summary:
1) The molecular mass of H2O (water) is 18 grams/mol.
2) The molecular mass of NaOH (sodium hydroxide) is 40 grams/mol.
3) The molecular mass of MgCl2 (magnesium chloride) is 95 grams/mol.