Module 3

Question 1

(S)

Answer 1

Solid

Question 2

(G)

Answer 2

Gas

Question 3

(L)

Answer 3

Liquid

Question 4

(Aq)

Answer 4

Aqueous solution

Question 5

GFM

Answer 5

Grand formula mass

Question 6

Formula for mass

Answer 6

m= Number of moles x GFM

Question 7

Formula for number of moles

Answer 7

Mass in grams / GFM

Question 8

Formula for GFM

Answer 8

Mass in grams/ no. of moles

Question 9

How to calculate the mass of product from a given mass of reactant

Answer 9

1. Calculate n, the number of moles, for the substance whose mass has been provided
2. Usle the “mole ratio” from the balanced equation to connect the chemical whose mass has been provided with the chemical whose mass we are trying to determine
3. Caluculate m, mass for unknown chemical

Question 10

Example 1. What mass of MgO is produced from 5g of Mg?

Answer 10

2Mg + O2 -> 2MgO

n=m/ GFM
= 5/24.5
=0.2 moles

2 moles of Mg -> 2 moles of MgO
0.2 moles of Mg-> 0.2 moles of MgO

m= n x GFM
= 0.2 x 40.5
= 8.1g

Question 11

Example. Calculate the mass of NaCl made from 710g of Cl2

Answer 11

2Na + Cl2 -> 2NaCl

n=m/ GFM
= 710/71
=10 moles

1 mole of Cl -> 2 moles of NaCl
10 moles of Cl ->20 moles of NaCl

m=n x GFM
= 20 x 58.5
= 1170g

Question 12

The 4 signs of a reaction

Answer 12

1. Gas produced
2. Colour change
3. Change in tempreature
4. Percipation

Question 13

Examples of everyday reations

Answer 13

Burning toast
Baking a cake
Digestion

Question 14

What properties can change to alter a reaction

Answer 14

Add a catalyst
Increase tempreture
Increase surface area
Increase concentration

Question 15

What is concentration

Answer 15

Concentration is a measure of how much solute is dissloved in a particular volume of solvent

Question 16

What happens if there is high concentration

Answer 16

Higher concentration = higher chance of a sucessful collison

Question 17

What happens If the temperature is is high in a reaction

Answer 17

The faster the reactants move and the greater the chance of a sucessful collison at high temperature

Question 18

In order to react something what has to happen

Answer 18

Atoms have to collide

Question 19

If there is more surface area what greater chance is there?

Answer 19

A greater chance of a sucessful collison

Question 20

What type of catalysts are there?

Answer 20

Biological (enzymes) or chemical

Question 21

What do chemial catalysts do?

Answer 21

~ speed up at reaction
~ lower tempreature of a reaction
~can be re-used
~ are chemically unchanged

Question 22

How does a catalyst work

Answer 22

The reactants move close together on the catalyst surface and react. The reaction speeds up

Question 23

Average rate equation

Answer 23

Average rate= change in quantity/ change in time

Question 24

What is (mol l -1)

Answer 24

Moles per liter to measure the concentration

Question 25

cm3 /s

Answer 25

centimeters per second (units of graph)

Question 26

equation to find mass

Answer 26

m=n x GFM

Question 27

The equation to find GFM

Answer 27

GFM= m/n

Question 28

What is the equation for finding the number of mole

Answer 28

n= m/ GFM