What number of molecules (or formula units) are present in 1.00 g of each of the compounds in Exercise 51?

Interpretation: The mass of compound is given. By using the mass, the number of molecules present of each of the compound given in exercise 51 is to be determined.

Concept introduction: The atomic mass is defined as the sum of number of protons and number of neutrons.

Molar mass of a substance is defined as the mass of the substance in gram of one mole of that compound.

The molar mass of any compound can be calculated by adding of atomic weight of individual atoms present in it.

The amount of substance containing 12 g of pure carbon is called a mole. One mole of atoms always contains 6.022×1023 molecules. The number of molecules in one mole is also called Avogadro’s number.

Hence,

(6.022×1023 atoms)(12 u1 atom)=12 g⇒1 u=16.022×1023  g

To determine: The number of molecules in 1.00 g of NH3 .

Given

The mass of NH3 is 1.00 g .

The molar mass of NH3 is,

(14.006+3×1.0079) g/mol=17.0297 g/mol

Formula

The number of moles in NH3 is calculated as,

Moles of NH3=Mass of NH3Molar mass of NH3

Substitute the values of mass and molar mass of NH3 in above equation.

Moles of NH3=Mass of NH3Molar mass of NH3=1.00 g17.0297 g/mol=0.0587 mol

The number of molecules in 1.00 g of NH3 is calculated using the formula,

Molecules of NH3=Moles of NH3(6

Interpretation: The mass of compound is given. By using the mass, the number of molecules present of each of the compound given in exercise 51 is to be determined.

Concept introduction: The atomic mass is defined as the sum of number of protons and number of neutrons.

Molar mass of a substance is defined as the mass of the substance in gram of one mole of that compound.

The molar mass of any compound can be calculated by adding of atomic weight of individual atoms present in it.

The amount of substance containing 12 g of pure carbon is called a mole. One mole of atoms always contains 6.022×1023 molecules. The number of molecules in one mole is also called Avogadro’s number.

Hence,

(6.022×1023 atoms)(12 u1 atom)=12 g⇒1 u=16.022×1023  g

To determine: The number of molecules in 1.00 g of N2H4 .

Interpretation: The mass of compound is given. By using the mass, the number of molecules present of each of the compound given in exercise 51 is to be determined.

Concept introduction: The atomic mass is defined as the sum of number of protons and number of neutrons.

Molar mass of a substance is defined as the mass of the substance in gram of one mole of that compound.

The molar mass of any compound can be calculated by adding of atomic weight of individual atoms present in it.

The amount of substance containing 12 g of pure carbon is called a mole. One mole of atoms always contains 6.022×1023 molecules. The number of molecules in one mole is also called Avogadro’s number.

Hence,

(6.022×1023 atoms)(12 u1 atom)=12 g⇒1 u=16.022×1023  g

To determine: The number of molecules in 1.00 g of (NH4)2Cr2O7 .