Chemistry

Question 1

Define Collision theory

Answer 1

In order to have successful collision (chemical reaction) Particles must have:
- Correct orientation
- Sufficient energy to overcome the activation energy

Question 1

Rate of reaction

Answer 1

Number of successful collisions per unit time

Question 1

Reactant - Products

Answer 1

For reactant particles to be converted into products, particles must collide with one other to break their bonds. The reactant particles are then able to rearrange and recombine to make new bonds, creating products. We call these reactions successful collisions.

Question 2

Activation energy

Answer 2

The minimum amount of energy a reactant must have in order to react i.e collisions occur with enough energy to break reactant bonds.

Question 3

Particle theory

Answer 3

All matter is made of particles and these particles are in constant motion.

Question 4

Exchange Reaction

Answer 4

When two soluble solutions are mixed together and the pairs of ions swap. If one of the new products is insoluble, it will form a precipitate. The other two ions remain dissolved.

Question 5

Displacement reaction

Answer 5

• Occur between a reactive metal and the ion of a less reactive metal.
• Reactive metal loses its electrons and becomes an ion while less reactive positive ion gains these electrons and converts back to solid form.

The negative ion will not take part in the reaction and remains dissolved. (spectator ion)

Question 6

Physical change

Answer 6

Appearance or state of a substance changes.

Question 7

Chemical change

Answer 7

Reshuffling of atoms where bonds are broken and rejoined. This results in new substances with different properties to the original reactants.

Question 8

Signs of chemical change

Answer 8

• change in colour
• Fizzing
• Light/heat
  -Precipitate formed
• New product

Question 9

Incomplete combustion

Answer 9

when a fuel reacts with insufficient oxygen to produce carbon monoxide, water, & sometimes CO2.

Question 10

Complete combustion

Answer 10

When a fuel reacts with a sufficient amount of oxygen to produce products CO2 and H2O.

Question 11

Neutralisation Reaction

Answer 11

1) Acid+Base–> Metal salt + water
2) Acid+Base–> metal salt+water+carbon dioxide

Question 12

Covalent bonding

Answer 12

A chemical bonding where electrons are shared between two or more non-metal atoms.

Question 13

Ionic Bonding

Answer 13

An attraction between positive cations and negative anions.

Question 14

Surface Area

Answer 14

• Definition: number of particles exposed and available to react.
• When surface area increases, rate of reaction increases.
• The larger the surface area, the more reactant particles exposed for collisions to occur on.
• Higher frequency of successful collisions.
• Rate of reaction increases.

Question 15

Temperature

Answer 15

Definition: the amount of kinetic energy in particles.
- as temp increases, Rate of reaction increases (vice versa)
- The higher the temp, the greater the kinetic energy, so the faster the particles move
-The reactant particles collide more often per unit time as more reactant particles collide more often per unit time as more reactant particles will have enough energy to overcome the activation energy barrier.
- Higher frequency and proportion of successful collisions.
- Rate of reaction increases [in context]

Question 16

Concentration

Answer 16

• Definition: The amount of particles in a given volume.
• rate of reaction increases by increasing concentration of reactants.
• The greater the concentration the more reactant particles available per unit volume.
• Higher frequency of successful collisions.
• Rate of reaction increases.