C4 - MOLE CONCEPT

Question 1

Means of ATOMIC MASS?

Answer 1

Mass of an atom in atomic mass unit (a.m.u)

Question 2

Value of a.m.u

Answer 2

1 a.m.u = 1.66054 x 10^-24
1 a.m.u = 1/12 atom Carbon

Question 3

Means of RELATIVE ATOMIC MASS?
Example

Answer 3

The relative atomic mass (weight) of an element is the average mass of one atom of the element.
Ex: H=1

Question 4

Means of RELATIVE MOLECULAR MASS?
Example

Answer 4

The sum of relative atomic mass of all atoms present in the formula.
Ex: Na2SO4
2(23) + 1(32) + 4(16)
142

Question 5

Means of MOLAR MASS?

Answer 5

The mass of one mole of a substance.
The molar mass of a substance is numerically equal to the relative atomic mass and relative molecular mass of the substance but expressed in g/mol.

Question 6

Formula of Molar Mass?

Answer 6

Molar mass = 1 mol substance

(No. of particle) x (R.A.M)
Unit: g/mol

Question 7

Means of AVOGADRO’S NUMBER?

Answer 7

Number of particles in 1 mole.
NA = 6.023 x 10^23

1 mole of atoms has 6.023 x 10^23

Question 8

Formula of AVOGADRO’S NUMBER

Answer 8

No. of particle = no. of mol x NA

Question 9

Convertion to Mass, Moles, and Atoms

Answer 9

Mass to Moles
(÷ molar mass)

Moles to Atom
(x NA)

Atom to Moles
(÷ NA)

Moles to Mass
(x molar mass)

Question 10

Means of Emperical Formula

Answer 10

Simplest, whole number ratio of the atoms of elements in a compound.

Question 11

Ways to determine Empirical Formula.
[2]

Answer 11

-masses of an element formed when a compound is decompose, or that react together to form a compound.
-percent composition.

Question 12

Table of Empirical Formula?

Answer 12

1. Element
2. % composition by mass (g)
3. R.A.M
4. No. of moles
5. Mole ratio
6. Simplest ratio (x n)

Question 13

Means of Molecular Formula.

Answer 13

Multiple of the empirical formula.

Question 14

Ways to determine Empirical Formula.

Answer 14

-know the empirical formula
-know mass of the compound