All Sciences

Question 1

Resultant force formula

Answer 1

Force = Mass x Acceleration

Question 2

Moment Formula

Answer 2

Force x perpendicular distance

Question 3

Work done formula

Answer 3

Force x Displacement

Question 4

Power formula

Answer 4

Work done / time OR Energy/time

Question 5

Wave formula

Answer 5

Velocity = frequency x wavelength OR Frequency = 1/ Period

Question 6

Charge formula

Answer 6

Charge(C) = current(A) x time(S)

Question 7

Potential difference across 2 points formula

Answer 7

V = IR , Pd = Current(A) x resistance(ohms)

Question 8

Potential difference formula

Answer 8

V = W/Q , Pd = Work done(J) / Charge(A)

Question 9

EMF electromagnetic force formula

Answer 9

Total work done (V) / Charge(A)

Question 10

EMF electromagnetic force formula

Answer 10

Total work done (V) / Charge(A)

Question 11

Electric power

Answer 11

P = IV , Power = Pd(V) x Current(A)

Question 12

Zinc in Sodium hydroxide and aqueous ammonia

Answer 12

White precipitate soluble in both of zinc hydroxide

Question 13

Calcium in sodium hydroxide and aqueous ammonia

Answer 13

White insoluble precipitate but no precipitate in aqueous ammonia

Question 14

Aluminium in sodium hydroxide and aqueous ammonia

Answer 14

Both produce white precipitate but insoluble in aqueous ammonia

Question 15

Copper (ll) in sodium hydroxide and aqueous ammonia

Answer 15

Blue precipitate in both but insoluble in sodium hydroxide

Question 16

Iron (ll) in sodium hydroxide and aqueous ammonia

Answer 16

Green precipitate produced but insoluble in both but on standing produces red brown iron (lll) hydroxide

Question 17

Iron(lll) in sodium hydroxide and aqueous ammonia

Answer 17

Red brown precipitate but insoluble in both

Question 18

Ammonium in sodium hydroxide and aqueous ammonia

Answer 18

No precipitate formed but sodium hydroxide make heated gas moist red limus paper blue

Question 19

Nitrate test

Answer 19

Sodium hydroxide and aluminium foil then warm
Effervescence with pungent gas which turns moist red litmus paper blue
Ammonia gas produced

Question 20

Carbonate test

Answer 20

Add dilute acid
Effervescence observed
White precipitate produced with lime water
Carbon dioxide produced

Question 21

Chloride test

Answer 21

Add dilute nitric acid with silver nitrate
White precipitate of silver chloride formed

Question 22

Sulfate test

Answer 22

Add dilute nitric acid and barium nitrate or Add dilute hydrochloric acid with barium chloride
White precipitate of barium sulfate formed

Question 23

Mass and mole

Answer 23

Mass of mole
No of moles x Mr

Question 24

Volume of gas

Answer 24

Vol of gas (dm3)
No of moles x Mr volume (24dm3)

Question 25

Concentration of solution

Answer 25

Mass and no of moles Concentration (g/dm3) x vol(dm3)

Question 26

Electric field definition

Answer 26

Region in which electrical charge experiences an electrical force

Question 27

Explain if sound travelled in water is different from air

Answer 27

Wavelength increases Speed of sound wave is higher in water than air Frequency higher and wavelength longer

Question 28

2 difference between microwave and sound wave

Answer 28

Microwave travel faster than sound wave Microwave travels in vacuum where sound waves travel through medium

Question 29

Conduction convection radiation

Answer 29

Conduction is through contact Convection is through water molecules Radiation is through electromagnetic waves

Question 30

How finely powered tablets affect reaction compared to normal tablets

Answer 30

More surface area Faster reaction Increase collision and frequ

Question 31

Define isotope

Answer 31

Same proton different neutron in the same element

Question 32

Define hydrocarbon

Answer 32

Only hydrogen and carbon present in compound

Question 33

Define relative molecular mass

Answer 33

Q molecular mass relative to 1/12 of C12 mole

Question 34

Why does carbon dioxide not conduct electricity

Answer 34

Neutral molecule No free moving ions

Question 35

Define inertia

Answer 35

Remains at a state of rest unless force acted on it

Question 36

What does cracking do

Answer 36

Break down into small hydrocarbons to meet the demand in resources

Question 37

How to raise ph soil for farmers

Answer 37

Add slacked lime or calcium hydroxide

Question 38

Define alloy

Answer 38

Mixture made up of 2 or more metals to increase strength

Question 39

Why speed remains constant even when force is applied

Answer 39

Resultant force acting is 0 Air resistance and friction are acting on the opposite side of the force

Question 40

Electromagnetic wave used for satellite television

Answer 40

Microwave

Question 41

Characteristics of mirror image

Answer 41

Magnified, virtual, upright

Question 42

State what is meant by frequency

Answer 42

Frequency is the number of complete waves produced per second

Question 43

How does longitudinal wave travel through air

Answer 43

The air particles vibrate in a direction parallel to the wave Creating a series of compression and rare fraction

Question 44

How earth wire protects user from electric shock

Answer 44

When fault occurs, the metal casing becomes live Earth wire conduct electrical current to earth Large current melts the fuse in the live wire and breaks the circuit

Question 45

Arrangement of particles in air

Answer 45

F (Force) A (Arrangement) - Randomly arranged, far apart M (Movement) - Move randomly at high speeds E (Energy)

Question 46

Cracking conditions

Answer 46

High temperature over catalyst

Question 47

Fermentation condition

Answer 47

Absence in oxygen 37 degrees celcius Carbohydrates Yeast

Question 48

What is the order by which elements are arranged in the periodic table

Answer 48

Through increasing proton (atomic) number

Question 49

Suggest the meaning clean energy

Answer 49

Do not release any atmospheric pollutants that maybe harmful for the environment

Question 50

Only magnitude

Answer 50

Scalar quantity

Question 51

Magnitude and direction

Answer 51

Vector quantity

Question 52

Example of scalar quantities

Answer 52

Length speed mass area

Question 53

Example of vector quantities

Answer 53

Displacement Velocity Acceleration

Question 54

Why some compounds cannot react with electricity at solid state

Answer 54

Giant lattice structure Ions have fixed position in solid Unable to conduct electricity Liquid state have free moving ions that carry charges

Question 55

Name 2 greenhouse gases

Answer 55

Carbon dioxide Methane

Question 56

Why bioethanol is a renewable and is a clean fuel

Answer 56

Can grow back Does not produce pollutants during combustion

Question 57

Why are biofuels for environmentally sustainable than fossil fuels

Answer 57

Sugarcane takes in carbon dioxide produced from combustion of bioethanol while carbon dioxide released by fossil fuels would not be offset

Question 58

Nitrogen air percentage

Answer 58

78%

Question 59

Oxygen air percentage

Answer 59

21%

Question 60

Carbon dioxide air percentage

Answer 60

0.01%

Question 61

Noble gases air percentage

Answer 61

1%

Question 62

2 factors required for rusting

Answer 62

Presence in oxygen Water

Question 63

Physical property of ethanoic acid

Answer 63

Conducts electricity at aqueous state Sour in taste Turns blue litmus paper red

Question 64

Why in order to achieve constant speed, acceleration has to be continuous

Answer 64

Acceleration caused by a change in velocity Since velocity is a vector quantity it has magnitude and direction Therefore acceleration is present

Question 65

Remote controls

Answer 65

Infrared waves

Question 66

Difference of molecules between solid and gas state

Answer 66

Regularly arranged vs randomly arranged Vibrate about fixed position vs move freely in high speeds Closely packed vs far apart

Question 67

Potential energy of pumping water up the reservoir

Answer 67

Gravitational potential energy

Question 68

How sound with higher pitch differs from lower pitch

Answer 68

Higher frequency and lower frequency