Definitions

Question 1

What is matter?
What is mass of an object?
What is volume?

Answer 1

Matter is anything that takes up space e.g solid, liquid, gas

The mass of an object is the amount of matter it contains measured in kilograms (kg)

The volume is the amount of space that the matter takes up

Question 2

Describe structure of solids

Answer 2

Solids retain a fixed shape

The particles are closely packed together in a regular structure and vibrate around a fixed position

Solids are not easily compressed

Question 3

Describe liquids

Answer 3

Liquids take up the shape of the container that they occupy

•The particles are closely packed together, but there is no regular arrangement

•The particles can vibrate and move past each other

•Liquids are not easily compressed

Question 4

Describe gases

Answer 4

Gases take up the shape of the container that they occupy

•The particles are spread out with no particular arrangement and can move freely

•Gases are easily compressed

Question 5

What is the weight of an object?

Answer 5

The weight of an object is the force of gravity acting upon its mass

The weight of an object is expressed in newtons

Question 6

What is force?
What equation is used for force?

Answer 6

Force is a push, a pull or other action that changes the motion of an object.

•It is equal to the mass of the object multiplied by the acceleration

•F = m x a

•Force is measured in Newtons

Question 7

What is work?
Equation for work?

Answer 7

Work is an expression of the force applied to an object multiplied by the distance across to which it is applied

•W =Fxd

•Work is measured in joule (J)

Question 8

What is energy?
The two types?

Answer 8

The ability to do work
•There are two types –
•Potential energy – energy that is stored
•Kinetic energy – energy being expended

Question 9

Describe net charge?

Answer 9

Atoms that have the same number of protons and electrons will have no net charge

•The charges cancel each other out

Question 10

Describe binding energy

Answer 10

The nucleus is held together by a strong nuclear force

•Creating a binding energy

•This is a measure of the amount of energy required to split the atom

Question 11

What are the electron shells names?
What does n equal in 2n^2

Answer 11

K,L,M,N

N= number of the shell

Question 12

What holds electrons in orbit?
What factors affect this?

Answer 12

Electrons are held in their orbits by binding energy

•This is dependent of several factors -
•How close the electron is to the nucleus
•How many protons there are in the nucleus

•The closer the electron is to the nucleus the stronger the binding energy

Question 13

How can an electron be removed from its orbit?

Answer 13

An electron can be removed from its orbit if it is struck with an energy greater than the binding energy

Question 14

What happens if ionisation occurs?
(X-ray production)

Answer 14

If this occurs in shell nearer the nucleus an electron from an outer shell will drop down to fill the inner shell vacancy

•Energy is released in the form of electromagnetic radiation – characteristic x-ray photons

•The orbit shells fill from the shell nearest the nucleus outwards as a vacancy in a shell makes it unstable

Question 15

What happens when heat is given to an object?

Answer 15

When heat is given to an object, the particles within it are given kinetic energy

•Resulting in the particles moving more

•An object with a higher kinetic energy is described at a higher temperature than an object at a lower kinetic energy

Question 16

Define temperature and heat

Answer 16

Temperature
Temperature, therefore, is a measure of hot or cold and is related to the average kinetic energy that the particles of an object have

Heat
Heat is the transfer of energy from one object of matter to another, or from one part of an object to another part

Question 17

How does a heat transfer occur?

Answer 17

Heat transfer occurs because of a temperature gradient

•Occurs from an area of high temperature to an area of lower temperature.

•This transfer of energy continues until the temperatures of the two objects – or the parts of the same object – are the same

Question 18

What is conduction?

Answer 18

The transfer of heat via direct molecular collision

•Results in a transfer of kinetic energy from higher to lower

•Conduction occurs in solids when there is a temperature gradient

Question 19

What is convection?

Answer 19

The transfer of heat through liquids or gases

•The particles closest to the heat source are heated by conduction

•These particles expand and become less dense, causing them to rise

•As they rise, further particles are drawn in from the side towards the heat source and undergo the same process

As the particles rise, they bump into other particles and heat transfer occurs, again by the process of conduction

•This causes the particles to cool down and fall; they can then be reheated and go through the process of rising, cooling, and falling again (because of heat transfer) and convection currents are created

Question 20

What is radiation?

Answer 20

The transfer of heat energy through waves

•As waves hit an object, kinetic energy is transferred to the object, causing an increase in temperature. This is how we feel in the heat from the sun

•Radiation is the only mechanism of heat transfer that can take place in a vacuum

Question 21

What is electromagnetic radiation?

Answer 21

An electric and magnetic disturbance through space at the speed of light

•Eg radiowaves, x-ray gamma rays

•The electromagnetic spectrum is a way of ordering the different elect radiations

Question 22

What is the same for all waves?

Define wavelength and frequency

Answer 22

Velocity

Wavelength - distance from one peak to another

•Frequency - number of cycles per second and in measured in Hertz (Hz)

Question 23

What is non ionising radiation?

Answer 23

Low energy radiation with a longer wavelength

•E.g. Radio waves and microwaves

•Visible light is the only electromagnetic radiation visible to the naked eye

Question 24

What is ionising radiation?

Answer 24

X-ray and gamma rays have the ability to ionize matter

•When a photon possesses sufficient energy it can remove an electron from an atom – ionisation

•When this occurs it causes damage to human tissue

Question 25

Define element

Answer 25

Elements are substances that cannot be broken down into simpler substances

Question 26

Define atomic number and atomic mass

Answer 26

The atomic number refers to the number of protons in the nucleus. It determines the chemical properties and defines the element. The atomic number is represented by the letter Z.

Atomic mass:
•The atomic mass is the combined number of protons and neutrons in the nucleus. It is represented by the letter A.

Question 27

Define isotope

Answer 27

Isotopes are different forms of the same element.
•Their atoms have the same number of protons but a different number of neutrons
•Therefore, they have a different mass number