Science - 3

Question 1

How is electricity a form of energy?

Answer 1

movement of electrons between two points.

Question 2

Identify some useful energy transfers involving electrical energy?

Answer 2

Kettles, microwaves and hairdryers

Question 3

What is the difference between static electricity and current electricity?

Answer 3

Static electricity does not move, it stays in the same place. Current electricity is when an electrical charge is given a path to move through.

Question 4

Explain what a conductor is:

Answer 4

Some electrons are free to leave

Question 5

Explain what a insulator is:

Answer 5

Electrons are tightly held and cannot leave

Question 6

What is static electricity?

Answer 6

occurs when charges collect on a surface (insulators) and do not flow away immediately

Question 7

3 uses of static electricity:

Answer 7

Photo copying, powder-coating, theatres

Question 8

Why can statics electricity be dangerous?

Answer 8

Electric shock, fires or explosions

Question 9

How do electrons move through a conductor?

Answer 9

In an electrical current e.g copper

Question 10

What is the difference between a series circuit and a parallel circuit?

Answer 10

A series circuit connects end to end in a loop. A parallel circuit components are connected side by side giving several different pathways.

Question 11

Unit for current

Answer 11

amps (A)

Question 12

What is current?

Answer 12

Current is the flow of electrons

Question 13

what is Ohm’s law?

Answer 13

In triangle V (voltage) on top, current (A) and resistance (R) on bottom.

Question 14

Energy is carried by what?

Answer 14

Energy is carried by electrons

Question 15

How do you measure energy differences?

Answer 15

Voltmeter

Question 16

What does voltage measure?

Answer 16

Energy

Question 17

What is power measured in?

Answer 17

Watts

Question 18

What is power?

Answer 18

Energy transferred in one second

Question 19

What is kilowatt hours?

Answer 19

The energy transferred by an appliance is measured in kilowatt hours or. KWH. 1 KWH is known as 1 unit of electricity.

Question 20

Name three methods of controlling electric currents:

Answer 20

Switch, fuses, circuit breakers

Question 21

Safety precautions for an electrical accident:

Answer 21

If you touch exposed wires your body becomes part of the circuit. Always disconnect the power in an emergency.

Question 22

What attraction and repulsion?

Answer 22

Opposite poles attract. Like poles repel.

Question 23

How do you tell if certain materials are magnetic / what happens inside of them?

Answer 23

Domains line up in series

Question 24

How does strength of magnetic feilds be changed?

Answer 24

increasing current, number of coils, and adding an iron core

Question 25

How are electricity and magnetism linked?

Answer 25

When an electrical charge flows in a wire, a magnetic field is formed around the wire.

Question 26

Positive and negative things about electromagnets:

Answer 26

They can be turned on and off. Strength can be changed.

Question 27

Why do elements gain or lose electrons?

Answer 27

So they can have a full valance or outer shell

Question 28

Formula for Hydrochloric acid:

Answer 28

HCL

Question 29

Formula for sulfuric acid:

Answer 29

H2SO4

Question 30

Formula for Nitric acid:

Answer 30

HNO3

Question 31

Why do elements combine in exact ratios to make electrically neutral compounds?

Answer 31

Result of the law of constant composition

Question 32

Define acids:

Answer 32

Compounds that release hydrogen ions when they dissolve in water

Question 33

List some properties of acids:

Answer 33

- Low pH -Turn blue litmus red

Question 34

List some properties of bases:

Answer 34

- High pH -Turn red litmus blue

Question 35

How much H+ ions are released from weak and strong acids?

Answer 35

Strong acids release lots of H+ ions, but weak acids only release a few

Question 36

Define bases:

Answer 36

Substance that mostly release hydroxide ions when they dissolve in water

Question 37

How much OH- ions are released from weak and strong bases:

Answer 37

Strong bases release a lot of OH-, but weak bases only release a few

Question 38

What is sulfuric, nitric, and hydrochloric acid into a combination:

Answer 38

Sulfate, nitrate, chloride

Question 39

Formula for calcium hydroxide:

Answer 39

Ca(OH)2

Question 40

Why do acids and bases react?

Answer 40

To neutralise eachother

Question 41

Formula for calcium carbonate:

Answer 41

CaCO3

Question 42

Describe the pH scale:

Answer 42

It runs from 0-14, with zero the most acidic and 14 the most alkali

Question 43

Define and indicator:

Answer 43

Natural dye that changes colour depending on whether it is placed in an acid or base

Question 44

What pH do neutral substances have?

Answer 44

pH 7

Question 45

What is the colour change in litmus in acid and base?

Answer 45

Acid - red Base - Blue

Question 46

What is the colour change in an universal indicator in acid and base?

Answer 46

Base - blue acid - red neutral - green

Question 47

What is the colour change in phenolphthalein in acid and base?

Answer 47

Base - Pink Acid - Clear

Question 48

How is the pH scale linked to the universal indicator?

Answer 48

The universal indicator is linked to the colours on the pH scale

Question 49

Describe a technique for making an indicator from a plant:

Answer 49

Red cabbage, smash, universal indicator

Question 50

What is salt a compound of?

Answer 50

Compound of metal ion and one or more non-metal ions ( not oxide )

Question 51

Are salts a neutral substance?

Answer 51

Yes, they can be formed during neutralisation reactions.

Question 52

How is water formed from H+ and OH- ions when acids neutralise bases?

Answer 52

The two combine to form water

Question 53

What is the general equation for neutralisation?

Answer 53

acid + base = salt + water

Question 54

What is the technique called for preparing salts in the library?

Answer 54

Neutralisation reaction

Question 55

Define reactants

Answer 55

Reactants are the starting substances that undergo a chemical change

Question 56

Define products

Answer 56

products are the substances that are formed as a result of the reaction

Question 57

What is reservered during chemical reactions

Answer 57

matter

Question 58

What is the point of balancing an equation?

Answer 58

law of conservation of mass is upheld

Question 59

What is the general equation for acid and metal carbonate neutralisation?

Answer 59

Acid+Metal Carbonate→Salt+Water+Carbon Dioxide

Question 60

What is the collision theory?

Answer 60

For a reaction to occur between two substances, their particles must collide with each other.

Question 61

What is the effect of temperature on reaction rate using collision theory?

Answer 61

Higher temperatures speed up reactions by increasing collision frequency and energy.

Question 62

What is the effect of surface area on reaction rate using collision theory?

Answer 62

Increased surface area speeds up reactions because it allows more collisions between reactants.

Question 63

What is an alklai?

Answer 63

A base that is soluble in water

Question 64

What is an independant variable?

Answer 64

changes

Question 65

what is a dependant variable?

Answer 65

stays the same

Question 66

What are some properties of acids

Answer 66

Sour Release H+ when dissolved in water Turn blue litmus paper red PH below 7 Turns universal indicator red, orange, yellow Strong acids release many H+ in water while weak acids release few H+

Question 67

What are some properties of bases

Answer 67

Bitter Release OH- when dissolved in water Turn red litmus paper blue PH above 7 Turns universal indicator blue, purple Strong bases release many OH- in water while weak bases release few OH-