3.1.2- Amount Of Substance

Question 1

Define Ar

Answer 1

1/12 mass of an atom of C-12

Question 2

Define Mr

Answer 2

1/12 mass of c-12

Question 3

State the symbol, unit and name of amount of substance

Answer 3

Symbol - n
Unit - mol
Name - moles

Question 4

What is Avogadros constant?

Answer 4

6.022 x 10^23

Question 5

If I have one mol of water molecules

How many
Water molecules
Hydrogen atoms
Oxygen atom

Answer 5

6. 022x10^23 water molecules
7. 044 x 10^23 hydrogen atoms
8. 023 x 10^23 oxygen atoms

Question 6

What is the equation to calculate moles?

Answer 6

n=m/ Mr

Question 7

Working out particles in a substance.

Answer 7

N=nL

Particles= moles x constant

Question 8

What is the ideal gas equation ?

Answer 8

pV=nRT

Question 9

What does each part of ideal gas equation mean?

Answer 9

P=pressure 
V= volume 
T= temperature 
R=gas constant 
N =moles

Question 10

What do you have to add to degrees to her kelvin

Answer 10

+ 273

Question 11

Define empirical formula

Answer 11

Simplest whole number ratio of atoms of each element in a compound.

Question 12

Molecular formula

Answer 12

The actual number of atoms of each element in a compound.

Question 13

Steps of finding empirical formula.

Answer 13

1) get data e.g. Gram or %
2) divide by the mr
3) divide by the smallest
4) make them all integers
5) write the formula

Question 14

What is the ion of:

Ammonium
Phosphate

Answer 14

• NH^4+

- PO4^3-

Question 15

What is the ion of:

Sulfate
Sulfite

Answer 15

SO^4 2-

SO^3 2-

Question 16

What is the ion of carbonate

Hydroxide

Answer 16

CO^3 2-

OH-

Question 17

What is the ion of
Nitrate
Hydrogen carbonate

Answer 17

NO^3 -

HCO^3 -

Question 18

Balanced equation should have

Answer 18

Both sides the same

Included state symbols

Question 19

Formula for percentage atom economy

Answer 19

Molecular mass of desired product
——————- X100
Sum of molecular masses of all reactant

Question 20

What does it mean if there is a higher atom economy?

Answer 20

Higher atom economy means less waste

Question 21

Formula for percentage yield

Answer 21

Mass of product
————- X100
Theoretical max mass

Question 22

Formula for concentration

Answer 22

N
— = C
V

C x V = N