Chemistry

Question 1

Meaning of opaque to describe physical properties

Answer 1

Opaque objects block light from travelling through them. Most of the light is either reflected by the object or absorbed and converted to thermal energy. Materials such as wood, stone, and metals are opaque to visible light.

Question 2

Meaning of transparent to describe physical properties?

Answer 2

allowing light to pass through so that objects behind can be distinctly seen.

Question 3

Meaning of translucent to describe physical properties?

Answer 3

Translucent means that light may pass through that material but images on the other side of that material are not clearly visible

Question 4

Meaning of malleable to describe physical properties

Answer 4

Malleability describes the property of a metal’s ability to be distorted below compression. It is a physical property of metals by which they can be hammered, shaped and rolled into a very thin sheet without rupturing.

Question 5

Meaning of ductile to describe physical properties

Answer 5

Ductility is the ability of a material to be drawn or plastically deformed without fracture

Question 6

Meaning of explosive to describe chemical properties?

Answer 6

An explosive is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure.

Question 7

Meaning of flammable to describe chemical properties?

Answer 7

Flammability is the ability of a chemical to burn or ignite, causing fire or combustion.

Question 8

Meaning of reactive to describe chemical properties?

Answer 8

In chemistry, reactivity is a measure of how readily a substance undergoes a chemical reaction.

Question 9

Meaning of toxic to describe chemical properties?

Answer 9

Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism.

Question 10

Meaning of corrosive to describe chemical properties?

Answer 10

Corrosives are materials that can attack and chemically destroy exposed body tissues. Corrosives can also damage or even destroy metal.

Question 11

How do you identify a physical property?

Answer 11

A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Physical properties include colour, density, hardness, and melting and boiling points.

Question 12

How do you identify a chemical change?

Answer 12

A chemical change always produces one or more types of matter that differ from the matter present before the change.

Question 13

What changes to atom happen when there is a physical change

Answer 13

No change in the bonding between atoms

Question 14

What changes in atoms happen when a chemical change occurs?

Answer 14

The atom bond breaks and involves the rearrangement of atoms?

Question 15

What does a chemical reaction do?

Answer 15

Involves energy being taken in and given out

Question 16

Is a physical or chemical change easier to change?

Answer 16

A physical change is much easier to reverse than a chemical change

Question 17

Where do atoms go in a chemical change?

Answer 17

In a chemical reaction, atoms and mass are conserved throughout.

Question 18

How to structure a chemical reaction?

Answer 18

Reactants are the materials that we begin with, these are on the LHS of the worded equation. Products are created as a result of the reactants reacting together. These are on the RHS of the worded equation.

Question 19

The arrow in a worded equation means?

Answer 19

reacts to produce

Question 20

What does it mean when a word is written above the arrow?

Answer 20

it is a catalyst or not a substance

Question 21

What state does ‘s’ symbolise?

Answer 21

Solid

Question 22

What state does ‘l’ symbolise?

Answer 22

liquid

Question 23

What state does ‘aq’ symbolise?

Answer 23

solution

Question 24

What state does ‘g’ symbolise?

Answer 24

gas

Question 25

Signs of a chemical change could be (2)?

Answer 25

A colour change; gas given off, new odour formed, a new substance appearing (precipitate), a substance disappearing, a change in temperature, light or sound produced

Question 26

Define flammability

Answer 26

Flammability is the ability of a substance to ignite (have a flame) and to continue burning

Question 27

Define corrosion

Answer 27

Corrosion is a chemical reaction where a metal reacts with oxygen; it usually involves water.

Question 28

The worded equation for the formation of rust is?

Answer 28

iron + water + oxygen -> rust (or iron oxide)

Question 29

Effects of corrosion?

Answer 29

Corrosion limits the use of metals for some purposes. e.g. ships, bridges or buildings

Question 30

Methods to counter corrosion?

Answer 30

coatings, paint, grease and other metals.