Question

How many moles is 55 g of Naci? 0.025 g of NaCO3?

Answer 1

Answer:

0.940mol &

0.000301mol respectively.

Explanation:

number of moles = given mass / molar mass

given mass of Nacl = 55g Molar mass = 23 + 35.5

n=m/M = 55g/58.5g/mol = 0.940mol

note- (add the atomic weights of sodium and chlorine to get the molar mass of Nacl.) = 58.5g/mol

similarly, NaCO3 = 23 + 12 + 16*3 = 83g/mol

n=m/M = 0.025g/83g/mol = 3.01 * 10^-4 = 0.000301mol

extra: If you ever get asked to put it in number of particles just use the relation of 1mole = 6.02 * 10^23 particles.