Reaction Rates, Salts And Electrolysis

Question 1

What are the four factors that affect rate of a reaction?

Answer 1

Temperature.

Concentration

Catalyst

Surface area of solids

Question 2

Describe three ways of measuring the rate of reaction?

Answer 2

Precipitation. Observe a mark through the solution and measure how long it takes to disappear the quicker the mark disappears the quicker the reaction.

Change in mass. You can measure the speed of reaction that produces a gas can be carried out on a mass balance. As the gas is realised the mass disappearing is easily measured.

The volume of the gas given off. This involves a gas syringe, the more gas given off during a given time the faster the reaction

Question 3

A student carried out an experiment to measure the effect of surface area on the reaction between marble and hydrochloric acid he measures the amount of gas given off at regular intervals. What factors must be he keep constant for it to be a fair test?

Answer 3

The temperature
Concentration
Same mass of marble

Question 4

Explain how higher temperature increases the frequency of successful collisions between particles

Answer 4

When the temperature is increased the particles all move quicker. If they are moving quicker they’re are going to collide more often

Question 5

Explain how higher concentration increases the frequency of successful collisions between particles.

Answer 5

If a solution is made more concentrated it means there are more particles of reactant knocking about between the water molecules which make collisions. Between the improbably Patrick led more likely.

Question 6

Explain how large surface area increases the frequencies of successful collisions between particles

Answer 6

If one of the reactants is a solid then breaking it up into smaller pieces will increase the total surface area. This means the particles in the the soliciting have more area to work on increasing the frequency of collisions

Question 7

What is activation energy?

Answer 7

Is the minimum amount of energy that is required to activate atoms or molecules to a condition in which they can undergo chemical transformation

Question 8

What are the disadvantages of using catalysts in industrial processes?

Answer 8

Catalysts can be ‘poisoned’ by impurities so they stop working.

Different reactions has different catalysts, so if you make more than one product you’ll need more than one catalysts.

Question 9

What are the advantages of using catalysts in industrial processes?

Answer 9

They never get used up

They increase the rate of reaction which saves a lot of money

Question 10

What is a exothermic reaction?

Answer 10

A reaction which transfers energy to the surroundings, usually in the form of heat and usually shown by a rise in temperature

Question 11

Name three examples of exothermic reactions?

Answer 11

Burning fuels (Combustion),
Neutralisation reactions (Acid+Alkali) 
Oxidation reactions

Question 12

What is the definition of a catalyst?

Answer 12

A catalyst is a substance which speeds up a reaction, without being changed or used up in the reaction

Question 13

What does the pH scale show?

Answer 13

The pH scale is a measure of how acidic or alkaline a solution is

Question 14

What type of ions are always present in acids?

Answer 14

+

H

Question 15

What type of ions are always present in alkalis?

Answer 15

_

OH

Question 16

What is neutralisation?

Answer 16

The reaction between an acid and a base (an alkali which is dissolved in water)

Question 17

What is the general equation for reacting an acid with a metal?

Answer 17

Acid + Metal –> salt + hydrogen

Question 18

Name a thing that doesn’t react at all with dilute acids?

Answer 18

Copper, because it’s less reactive than hydrogen

Question 19

What type of salts does hydrochloric acid produce?

Answer 19

Chloride salts

Question 20

Why type of reaction is

“Acid+metal oxide”

Or

“Acid+metal hydroxide”

Answer 20

Neutralisation

Question 21

How can you tell when a neutralisation reaction is complete if both the base and the salt are soluble in water?

Answer 21

An indicator is used to show that a neutralisation reaction is over.

Question 22

Give a practical use of precipitation reactions?

Answer 22

Can be used to remove poisonous ions, such as lead from drinking water.

Question 23

What is electrolysis?

Answer 23

Passing an electrical current through an ionic substance that’s molten or in a solution, it breaks down into the elements its made of this is called electrolysis.

Question 24

Explain why only liquids can be electrolysed?

Answer 24

It requires a liquid to conduct the electricity, called the electrolyte

Question 25

Give one industrial use of sodium hydroxide and two uses of chlorine?

Answer 25

Sodium Hydroxide- Soap Chlorine - Production of Bleach & Plastics

Question 26

why is cryolite used during the electrolysis of aluminium oxide?

Answer 26

Is used to lower the temperature (and cost)

Question 27

Give two different uses of electroplating?

Answer 27

Decoration- eg silver plated cups | Conduction

Question 28

What is the general word equation for neutralisation?

Answer 28

Acid + base --> salt + water

Question 29

What is the general equation for neutralisation in terms of ions?

Answer 29

+ _ H + OH ----> H20 (aq) (aq) (l)

Question 30

What physical state does this symbol represent? (aq)

Answer 30

Dissolved in water

Question 31

What physical state does this symbol represent? (l)

Answer 31

Liquid

Question 32

What physical state does this symbol represent? (s)

Answer 32

Solid

Question 33

What physical state does this symbol represent? (g)

Answer 33

Gas

Question 34

What type of salts does sulfuric acid produce?

Answer 34

Sulfate salts