Chemistry Grade 10

Question 1

Reactants & their products:

Acid Reactions

Answer 1

1. Acid + Metal —-> Salt + Hydrogen Gas
2. Acid + Metal Oxide —–> Salt + Water
3. Acid + Metal carbonate —–> Salt + CO2 + water
4. Acid + Base ——> Salt + Water

Question 2

Define

Titration

Answer 2

Calculation of conc. Of unknown acid or base

Question 3

Materials needed for

Titration

Answer 3

Burette = Rinse with water and followed by either acid or Base.
Note : Burette is used to calculate unknown concentration of any sample of either acid or base.

Pipette ( We used Measuring cylinder)
Rinse with Water and follow the opposite to burette.
Note : It has known Concentration of either Acid or Base.

Question 4

Formula of

Complete/Incomplete Combustion

Answer 4

Complete: CxHy + O2 ——-> CO2 + H2O

Incomplete: CxHy + O2 ——> CO + H2O

CO is Toxic gas than CO2. CO blocks the respiratory Gland to Deliver Oxygen

Question 5

Changes of Indicators for acid and base

Answer 5

Phenolphthalein:
Acid=No change
Base=Pink

Methyl Orange:
Acid=Red
Base=Yellow

Blue litmus:
Acid=Red
Base=No change

Red Litmus:
Acid=No change
Base=Blue

Universal indicator (pH):
Acid=pH<7 ( Red, orange ,Pink)
Base=pH>7 (Green , Blue )

Question 6

Identify and explain

Variables that affect the rate of reaction.

Answer 6

• Heat: As the temperature increases, more kinetic energy is present. Particles then move faster.
• Concentration: Increase of concentration means there’s more reactants in a volume that can collide with each other.
• Surface area: The increase of surface area of reactants ensure that they have a higher probability colliding with other reactants.

Question 7

Explain

Collision Theory

Answer 7

Collision theory states that in order for a reaction to occur:
* The particles must collide with each other (proper orientation)
* The collision must have sufficient energy to cause a reaction i.e. enough energy to break bonds

Question 8

How to find

%Purity

Answer 8

Mass of Pure sample / Mass of initial reactant x 100 = % Purity

Question 9

Formula

Finding Concentration/Volume in Titration

Answer 9

C1 * V1 = C2 * V2

C=concentration
V=Volume

Question 10

Formula of

pH, pOH, & Kw

With log10

Answer 10

• pH = -log10(H+)
• pOH = -log(OH-)
• Kw = (O+)(OH-) =10^-14