Compounds, Chemical Formulae, Equations And Acids

Question 1

Compare molecules and compounds

Answer 1

A molecule is a group of two or more atoms chemically bonded together, while a compound is a substance formed by combining two or more different elements in a fixed ratio

Question 2

What is the name of H-?

Answer 2

Hydride ion

Question 3

Hydroxide charge and formula?

Answer 3

OH-

Question 4

Carbonate charge and formula?

Answer 4

CO3 2-

Question 5

Sulfate charge and formula?

Answer 5

SO4 2-

Question 6

Nitrate charge and formula?

Answer 6

NO3 -

Question 7

Ammonium charge and formula?

Answer 7

NH4 +

Question 8

Phosphate charge and formula?

Answer 8

PO4 3-

Question 9

What do all negatively charged ions end in?

Answer 9

-ide

Question 10

Write a balanced symbol equation for the reaction of methane with oxygen. Include state symbols (2)

Answer 10

CH4 (g) + O2 (g) -> 2H2O + CO2

Question 11

Give the symbol equations for all the relevant acids

Answer 11

HCl
HNO3
HSO4
HPO4
CH3COOH (ethanoic acid)

Question 12

Give the symbol equations of 4 bases

Answer 12

CaOH2
NH3
KOH
NaOH

Question 13

What is an acid

Answer 13

A proton (hydride) donor

Question 14

Why are hydride ions known as protons

Answer 14

Because they weigh the same as a proton

Question 15

Compare strong and weak acids. (2)

Answer 15

A strong acid completely dissociates into its ions in aqueous solution
A weak acid partially dissociates into its ions in aqueous solution

Question 16

What is a base?

Answer 16

A proton (hydride) acceptor
Takes the hydrogen ions from acids

Question 17

Write an ionic equation for the reaction of ammonia with sulphuric acid. Ignore spectator ions. (1)

Answer 17

NH3+ H+ -> NH4+

Question 18

Write an ionic equation for the reaction of potassium carbonate with an unknown acid. (1)

Answer 18

CO3 2- + H+ -> CO2 + H2O

just the non-spectator ions need to be shown

Question 19

What are alkalis?

Answer 19

Specific types of bases which release OH- ions when dissolved in water (aq)

Question 20

Give 3 named examples of alkalis

Answer 20

Ammonium hydroxide
Sodium hydroxide
Potassium hydroxide

allow any other correctly named examples

Question 21

What is meant by a salt? (2)

Answer 21

An ionic compound which is produced when the Hydride ion of an acid is replaced by a metal ion or ammonium

Question 22

What is formed when an acid reacts with ammonia?

Answer 22

An ammonium salt

(e.g NH4Cl)

Question 23

What is formed when an acid reacts with a metal oxide?

Answer 23

A Salt and water

Question 24

What is formed when an acid reacts with a metal hydroxide?

Answer 24

A salt and water

Question 25

What is formed when a metal and an acid react?

Answer 25

A salt and hydrogen (MASH)

Question 26

What is formed when a carbonate is reacted with an acid?

Answer 26

A salt, carbon dioxide and water

Question 27

Which nitrites are soluble in water?

Answer 27

All nitrites are soluble in water

Question 28

State whether sodium, potassium and ammonium salts are soluble in water

Answer 28

All Na , K and NH4 salts are soluble in water

Question 29

Which chlorides are soluble in water?

Answer 29

All of them except AgCl

Question 30

Which sulfates are soluble in water?

Answer 30

All sulfates are soluble in water except BaSO4 and Ag2SO4

Question 31

Which carbonates are soluble in water?

Answer 31

All carbonates are soluble in water except Na2CO3, K2CO3 and (NH4)2CO3

Question 32

Which halide salts are soluble in water?

Answer 32

None of them except AgF

Question 33

What is the formula of silver oxide?

Answer 33

Ag2O (the charge of a silver ion is 1+)

Question 34

What is the formula of zinc nitrate?

Answer 34

Zn(NO3)2 (the charge of a zinc ion is 2+)

Question 35

What is meant by a binary compound?

Answer 35

A compound containing only 2 elements e.g hydroxide

Question 36

What is a cation?

Answer 36

A charged substance with more protons than electrons (positively charged)

Question 37

What is an anion?

Answer 37

A charged substance with more electrons than protons (negatively charged)

Question 38

A student adds an excess of hydrochloric acid to magnesium oxide and magnesium hydroxide. State two observations the student would make

Answer 38

Solid dissolves Effervescence (bubbling)

Question 39

What are poly atomic ions?

Answer 39

An ion comprised of more than one atoms of different elements (e.g NH4)

Question 40

Formula and charge of a sulphide ion?

Answer 40

SO3 2- Same as SO4

Question 41

How can CaCO3 be used to combat stomach acid? Use an equation to illustrate this. (2)

Answer 41

CaCO3 + 2HCl -> CaCl2 + H2O + CO2 It neutralises hydrochloric acid (as water is produced)

Question 42

What are the steps for balancing a hard equation? (4)

Answer 42

1• Balance metals 2• Balance non-metals (except H+O) 3• Balance H+O 4• Balance diatomic molecules

Question 43

What base would neutralise H2SO4? how do you know?

Answer 43

Any group 2 hydroxide (BaOH2- same OH- and H+ ions, BaSO4 formed)

Question 44

Does the anion or cation show electrons in dot and cross diagrams?

Answer 44

Anion

Question 45

Why might a molecule of H2O have an Mr of 20gmol-1?

Answer 45

O18 isotope (due to different number of neutrons)

Question 46

What acids are to remember, which can also form salts?

Answer 46

Carboxylic acids- COOH- H lost to base

Question 47

Formula and charge of a sulphite ion?

Answer 47

SO3 2-

Question 48

Formula and charge of a hydrogen carbonate ion?

Answer 48

HCO3 -

Question 49

Charge of zinc and silver ions

Answer 49

Zn2+ Ag+

Question 50

Give 3 examples of bases (exc. alkalis)

Answer 50

Metal oxides, metal carbonates, metal hydroxides

Question 51

Formula for Bromate (V)

Answer 51

BrO3 -

Question 52

Formula for dichromate (VI)

Answer 52

Cr2O7 2-