SC8

Question 1

How do you know when a solution is neutral?

Answer 1

Solutions with a pH of 7

Question 2

How do you know when a solution is acidic?

Answer 2

When they have a pH of less than 7

Question 3

How do you know when a solution is alkaline?

Answer 3

When they have a pH greater than 7

Question 4

How do you find the pH of a solution?

Answer 4

Use universal indicator

Question 5

When are polyatomic ions formed?

Answer 5

They’re formed when small groups of atoms, held together by covalent bonds, lose or gain electrons

Question 6

What do acids produce when they’re dissolved in water?

Answer 6

Excess of hydrogen ions

Question 7

What do alkaline produce when dissolved in water?

Answer 7

Excess of hydroxide ions

Question 8

The higher the number of hydrogen ions in a certain volume…

Answer 8

The higher the concentration
Higher concentration=more acidic
Lower pH

Question 9

The higher the concentration of hydroxide ions…

Answer 9

More alkaline the solution

Higher pH

Question 10

What is the concentration like in neutral solutions?

Answer 10

Contain low, equal concentrations of hydrogen and hydroxide ions

Question 11

What happens to the pH if the concentration of hydrogen ions is increased by a factor of 10?

Answer 11

pH decreases by 1

Question 12

What happens to the pH if the concentration of hydrogen ions is decreased by a factor of 10?

Answer 12

pH increases by 1

Question 13

What are strong acids?

Answer 13

Their molecules dissociate into ions when dissolved in water and produce high concentration of hydrogen ions

Question 14

What are weak acids?

Answer 14

Don’t dissociate completely into ions when dissolved in water

Question 15

What are bases?

Answer 15

They are substances that neutralise acids to form salt and water

All metal oxides are bases

Question 16

What happens during neutralisation?

Answer 16

Hydrogen ions combine with oxide ions to form water

Removes hydrogen ions so pH increases

Question 17

How are salts produced during neutralisation?

Answer 17

Replacing hydrogen ions with metal ions

Question 18

How do you make sure the prepared salt is pure?

Answer 18

Filtered to remove residue from filtrate leaving salt and water
Then allowed to evaporate to crystallise
If water evaporates slowly= bigger crystals

Question 19

Which type of bases are soluble (dissolve in water)

Answer 19

Alkali bases

Question 20

Where are the hydroxide bases found?

Answer 20

Group 1 and 2

Question 21

Why is the formula for group 2 hydroxides MOH(2)

Answer 21

Ions formed by group 2 have 2+ charge but hydroxide ions have 1- charge
Brackets show that 2 OH ions are needed to produce a neutral compound

Question 22

How do you obtain a neutral solution?

Answer 22

Mix together acid and alkali in right proportions so solution contains water and desired salt

Question 23

What is the burette’s role during titration?

Answer 23

Used to add acid to fixed volume of alkaline in a conical flask

Controlled using tap at bottom

Question 24

What is the role of the pipette in titration?

Answer 24

More accurate and repeatable way of measuring out alkali for conical flask

Few drops of indicator added to alkali to follow reaction

Question 25

When is the end point in titration?

Answer 25

Indicator changes colour | Indicator used are methyl orange or phenolphthalein

Question 26

How do you make pure dry salts from titration

Answer 26

Carry out titration Note exact volume of acid needed to neutralise alkaline Use burette to add correct volume of acid (without indicator) Evaporate water from solution formed

Question 27

How do metals such as copper and silver react with dilute acids?

Answer 27

Not at all

Question 28

How do metals such as potassium and sodium react with dilute acids?

Answer 28

React explosively

Question 29

How do metals such as magnesium and zinc react with dilute acids?

Answer 29

React steadily as in the middle of reactivity series

Question 30

What is effervescence?

Answer 30

When hydrogen gas bubbles are produced Reaction also produces salt

Question 31

What are spectator ions?

Answer 31

Ions that don’t change during reaction

Question 32

What happens when a metal reacts with a carbonate?

Answer 32

Produces salt, water and carbonate

Question 33

What harkens during the reaction with a metal and carbonate?

Answer 33

Hydrogen ions from acid react with the carbonate ions to form water and carbonate dioxide molecules

Question 34

How do you test for carbon dioxide?

Answer 34

Bubble gas through limewater | If carbon dioxide present, limewater turns milky

Question 35

What is a precipitation reaction?

Answer 35

Where soluble substances in solutions cause an insoluble precipitate to form

Question 36

Which substances are soluble in water?

Answer 36

Sodium, potassium and ammonium salts, carbonate & hydroxides All nitrates Most chlorides and sulfates

Question 37

Which substances are insoluble in water?

Answer 37

Silver, lead chlorides Lead, barium,calcium sulfates Most carbonates and hydroxides

Question 38

How do you predict whether a precipitate forms?

Answer 38

Precipitate will form if both of the products aren’t soluble Only form if insoluble

Question 39

How do you prepare insoluble salts?

Answer 39

Mix 2 solutions in beaker and then filter mixture Pour a little bit of distilled water through funnel Remove filter paper containing precipitate and dry