Topic 3 - Chemical Changes (Year 10)

Question 1

What ion is produces by all alkalis in aqueous solutions?

Answer 1

OH^-

Question 2

What ion is produces by all acidic in aqueous solutions?

Answer 2

H⁺

Question 3

Whatis the pH of a neutral solution?

Answer 3

7

Question 4

Whatis the pH of an alkaline solution?

Answer 4

Anything above 7

Question 5

Whatis the pH of a acidic solution?

Answer 5

Anything below 7

Question 6

True or False: Alkalis have a pH of more than 7?

Answer 6

True, remember a neutral solution has a pH of exactly 7

Question 7

What type of reaction occure when hydrochloric acid reacts with the potassium hydroxide?

Answer 7

Neutralisation

Question 8

Complete the equation: Acid + Alkali →

Answer 8

Salt + Water

Question 9

Complete the equation: Hydrochloric acid + Potassium hydroxide →

Answer 9

Potassium Chloride + Water

Question 10

Define the term: Indicator

Answer 10

a compound that changes colour at a specific pH value or in the presence of a particular substance

Question 11

Methy orange truns red in the presence of what solution?

Answer 11

An acidic Solution

Question 12

Phenolphthalein turns pink in the presences of what solution?

Answer 12

Alkaline solution

Question 13

Phenolphthalein turns colourless in the presences of what solution?

Answer 13

Acidic solution

Question 14

Complete the equation: H⁺ + OH^- →

Answer 14

H₂O

Question 15

What is the formula for hydrochloric acid?

Answer 15

HCl

Question 16

What is the formula for sulfuric acid?

Answer 16

H₂SO₄

Question 17

What is the formula for nitric acid?

Answer 17

HNO₃

Question 18

Define the term: Ionisation

Answer 18

The splitting up of a compound into separate smaller ions

Question 19

What is the equation for the dissociation of Hydrochloric Acid (HCl)?

Answer 19

HCl → H⁺ + Cl^-

Question 20

Define the term: Concentration

Answer 20

Relative amount of a particular substance contained within a solution or mixture or in a particular volume.

Question 21

Define the term: Alkali

Answer 21

A solution with a pH of more than 7 and that contains an excess of hydroxide (OH^–) ions.

Question 22

Define the term: Base

Answer 22

Any substance, soluble or insoluble, that neutralises an acid, forming a salt and water only.

Question 23

Define the term: Soluble

Answer 23

Soluble means something that will dissolve

Question 24

Define the term: Insoluble

Answer 24

Insoluble means something that will not dissolve

Question 25

Explain the difference between an alkali and a base

Answer 25

A base is a chemical which will react with an acid to form a salt and water only. An alkali is a water-soluble base.

Question 26

What will be produced if sulfuric acid reacts with a metal?

Answer 26

Metal sulfate and hydrogen

Question 27

Name the products of the reaction between sulfuric acid and copper oxide

Answer 27

Copper Sulfate and water

Question 28

Explain how you could make copper sulfate (A soluble salt from an insoluble base)?

Answer 28

1. Gently heat the acid. 2. Add insoluble base (Copper Oxide). 3. Filter off excess insoluble base. 4. Eveporate off excess water to leave crystals

Question 29

Complete the equation: Acid + Metal Oxide →

Answer 29

Salt + Water

Question 30

Complete the equation: Acid + Metal →

Answer 30

Salt + Hydrogen

Question 31

Complete the equation: Acid + Metal Carbonate →

Answer 31

Salt + Water + Carbon Dioxide

Question 32

How do you test for hydrogen?

Answer 32

Take a light splint and place it into a tube containing the gas, it should produce a squeaky pop (Squeaky Pop Test)

Question 33

How do you test for Carbon Dioxide?

Answer 33

Bubble the gas through lime water. The lime water will go from clear to cloudy

Question 34

True or False: Sodium Nitrate is soluble?

Answer 34

True, all nitrates are soluble

Question 35

True or False: Magnesium chloride is insoluble?

Answer 35

False: common chlorides are soluble except those of silver and lead

Question 36

True or False: Barium Carbonate is insoluble?

Answer 36

True, common carbonates and hydroxides are insoluble except those of sodium, potassium and ammonium

Question 37

True or False: Calcium Sulfate is insoluble?

Answer 37

False, common sulfates are soluble except those of lead, barium and calcium

Question 38

True or False: Potassium Chloride is soluble?

Answer 38

True, all. Common sodium, potassium and ammonium salts are soluble

Question 39

True or False: Precipitation reactions can be used to make insoluble salts by mixing an insoluble salt with a soluble salt?

Answer 39

False, Precipitation reactions occur between two soluble salts to form an insoluble salt

Question 40

How do you make an insoluble salt?

Answer 40

1. Mix two insoluble salts together that produce a precipitate. 2. Filter off the unwanted solution. 3. Dry the remaining salt retained through filtration

Question 41

Why would we use a titration?

Answer 41

To react accurately, exact amounts of an acid and an alkali together.

Question 42

How do you carry out a titration?

Answer 42

1. Add acid into a beaker and alkali into your burette. 2. Check the pH of your acid. 3. Add the akali dropwise, constantly checking the pH, until you get a neutral solution

Question 43

Write the equation for the dissociation of HCl

Answer 43

H⁺ + Cl^-

Question 44

Write the equation for the dissociation of H₂SO₄

Answer 44

2H⁺ + SO₄^2-

Question 45

Write the equation for the dissociation of HNO₃

Answer 45

H⁺ + NO₃^-

Question 46

What is the formula for a nitrate ion?

Answer 46

NO₃^-

Question 47

What is the formula for a sulfate ion?

Answer 47

SO₄^2-

Question 48

What is the formula for a chloride ion?

Answer 48

Cl^-

Question 49

How does an indicator show the acidity or alkalinity of solutions?

Answer 49

by changing colour

Question 50

What happens in all chemical reactions?

Answer 50

new substances are formed

Question 51

Which ion is in excess in all acidic solutions?

Answer 51

hydrogen ions or H+ ions

Question 52

What is meant by a strong acid?

Answer 52

An acid that fully dissociates

Question 53

What is meant by a weak acid?

Answer 53

An acid that only partly dissociates

Question 54

What is a more accurate methof of testing pH?

Answer 54

pH probe - give an exact reading of the pH of a solutionn

Question 55

Give a disadvantage of Universal indicator

Answer 55

Due to it beinng a scale can be hard to tell the pH exactly

Question 56

What word describes a solution that contains a large amount of solute in a small volume of solvent?

Answer 56

concentrated

Question 57

What name is given to substances that react with acids to form a salt and water only?

Answer 57

bases (bases are metal oxides and hydroxides, soluble bases are alkalis)

Question 58

What colour is phenolphthalein in acidic solutions?

Answer 58

colourless – not ‘clear’

Question 59

Name a piece of apparatus used to measure volumes of liquid.

Answer 59

measuring cylinder/pipette/burette

Question 60

What is seen when magnesium is added to dilute sulfuric acid?

Answer 60

effervescence/fizzing/bubbles (yes you know this is hydrogen, but you can not see that!!)

Question 61

How do you test for oxygen?

Answer 61

Get a boiling tube of the gas, place in a glowing splint, the splinnnt will relight

Question 62

How do you test for chlorine?

Answer 62

Damp blue litmus paper bleaches/goes white

Question 63

Why do you heat the acid when making copper sulfate?

Answer 63

Speed up rate of reaction

Question 64

When making copper sulfate you add copper oxide to heated sulfuric acid. Why is copper oxide added in excess?

Answer 64

To make sure that all acid has been reacted - makes the crystallisation step safer