calculate molar mass??

Question

H2)
I2
KOH
NH3

i appreciate the answers guys but can u tell me how u get them too.

Answer 1

Look up the atomic mass of each on the periodic table. Multiply the atomic mass by the number of each atom in the equation. Add up the mass of each.

H2SO4 = 2 H, 1 S, 4 O

H = 1 x 2 = 2
S = 32 x 1 = 32
O = 16 x 4 = 64
total = 2 + 32 + 64 = 100

Mg(NO3)2 = 1 Mg, 2 N, 6 O

Mg = 24.3 x 1 = 24.3
N = 14 x 2 = 28
O = 16 x 6 = 96
total = 24.3 + 28 + 96 = 148.3

Answer 2

Use a periodic table. Each element on the periodic table should show a single number at the top (that is the atomic number and it is also the number of protons) and the number at the bottom is the atomic mass (or the molar mass in grams/mole and it is the mass of the element). Use the atomic mass to calculate the molar mass. Your example, H2, means there are 2 Hydrogen atoms. You know that the mass of Hydrogen is approximately 1.008 from the periodic table, so, the mass of 2 Hydrogen atoms is 2 times 1.008. Hence, the molar mass of H2 is 2.016 grams.

Answer 3

You need to grab a periodic table...add up all different masses of the atoms. For example, the first one would be 1.0079 (the molar mass of Hydrogen) times 2 (the number of hydrogens)