Chemistry Key Terms

Question 1

What is: an ACID

Answer 1

A molecule that releases H⁺ ions in water

Question 2

What is: Activation energy

Answer 2

The minimum energy barrier which must be overcome before particles that can collide can react

Question 3

What is: Atom

Answer 3

The smallest unit of matter

Question 4

What is: Atomic number

Answer 4

Defines the element, gives the number of protons (& hence electrons) and tells you the position on the periodic table.

Question 5

What is: a BASE

Answer 5

A molecule that releases hydroxide ions (OH⁻) in water or reacts with water to form OH⁻ ions.

Question 6

What is: a Catalyst

Answer 6

Any substance which increases the rate of reaction by lowering the activation energy.

Question 7

What is: Collision theory

Answer 7

The set of rules that determine whether a successful collision between particles,and therefore a reaction, will occur: “particles must collide with enough energy and in the right orientation for a successful collision to occur.”

Question 8

What is: Concentration

Answer 8

The amount of particles in a set volume. e.g 0.15molL¯¹

Question 9

What is: Electron arrangement

Answer 9

How you show how many electrons are in each shell of an atom. The electron arrangement rule is: 2,8,8

Question 10

What is: The Electron shell

Answer 10

Where the electrons are held they are contained in the shells and orbit the nucleus of the atom.

Question 11

What is: Electrons

Answer 11

Small particles that are contained in an atoms shell and orbit the nucleus, they have a negative charge.

Question 12

What is: Universal Indicator

Answer 12

A solution that you use to determine whether a solution is acidic, neutral or basic (a base). It turns the colour of the pH of the solution.

Question 13

What is: Litmus paper

Answer 13

Used to show you whether a solution is acidic, neutral or basic (a base) there is blue litmus paper and red litmus paper. Blue stays blue in a base or neutral and turns red in an acid. Red stays red in an acid or neutral and goes blue in a base.

Question 14

What is: An ion

Answer 14

An atom or group of atoms with a charge positive (+) or negative (-). An atom becomes an ion by GAINING or LOSING ELECTRONS in order to have a FULL OUTER/VALENCE SHELL in order to be STABLE.

Question 15

What is: An ionic bond

Answer 15

The electrostatic attraction which holds together a positively charged ion (cation) and a negatively charged ion (anion).

Question 16

What is: An ionic compound

Answer 16

Formed from combining a POSITIVE and NEGATIVE ion. MUST be NEUTRAL in charge.

Question 17

What is: Mass number

Answer 17

The number of protons and neutrons together.

Question 18

What is: A neutralization reaction

Answer 18

A reaction between an ACID and a BASE which produces a SALT and WATER.

Question 19

What is: A neutron

Answer 19

A particle that is neutral in charge. It is found in the nucleus/center of an atom.

Question 20

What is: Nucleus

Answer 20

The center of an atom where the protons and neutrons are found.

Question 21

What is: pH scale

Answer 21

A scale from 0-14 that measures how acidic, neutral or basic a solution is. 0-2 is red=STRONG ACID, 3-4 is orange=WEAK ACID 5-6 is yellow=WEAK ACID, 7 is green=NEUTRAL, 8-11 is blue=WEAK BASE/ALKALI, 12-14 is purple=STRONG BASE/ALKALI

Question 22

What is: pH

Answer 22

A measurement of how many H⁺ ions there are compared to how many OH⁻ ions there are.

Question 23

What is: Proton

Answer 23

A particle with a positive (+) charge. It is located in the nucleus/center of an atom.

Question 24

What is: Rate of reaction

Answer 24

The rate is how quickly chemicals react. In order for 2 chemicals to react they have to COLLIDE with enough energy and correct orientation. PARTICLES will be used to describe any element or compound (e.g Mg or HCl). The rate of reaction is the NUMBER OF REACTIONS per second/or per unit of time. the factors effecting the rate of reaction are: SURFACE AREA, TEMPERATURE, CONCENTRATION and CATALYSTS.

Question 25

What is: Valence electrons

Answer 25

The electrons found in the valence shell/outer shell of an atom.

Question 26

What is: Valence shell

Answer 26

The outer shell of an atom