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CCEA GCSE Chemistry > Symbols, Formulae & Equations > Flashcards

Symbols, Formulae & Equations Flashcards

1
Q

What is a Chemical Symbol?

3 marks

A
  • Represents each Element in the Periodic Table.

- Has 1-2 letters; first letter must be a capital, second letter must be lower case.

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2
Q

Give an example of a Chemical Symbol.

2 marks

A

Mg is the correct symbol for magnesium, but mg, mG and MG are wrong.

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3
Q

Describe Diatomic Elements.

4 marks

A
  • The formulae for most elements is just their symbol, except some Non-Metal Elements known as Diatomic Elements .
  • They contain 2 Atoms of the Same Element Covalently Bonded together.
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4
Q

What are Diatomic Elements?

3 marks

A

Diatomic Elements are Non-Metal Elements that contain 2 Atoms of the Same Element Covalently Bonded together.

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5
Q

Give the Molecular formula of the following Diatomic Elements.

Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, Iodine, Astatine

(8 marks)

A 
Hydrogen - H2
Nitrogen - N2
Oxygen - O2
Fluorine - F2
Chlorine - Cl2
Bromine - Br2
Iodine - I2
Astatine - At2
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6
Q

Give the Molecular formula of Hydrogen (Diatomic Element).

1 mark

A

H2

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7
Q

Give the Molecular formula of Nitrogen (Diatomic Element).

1 mark

A

N2

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8
Q

Give the Molecular formula of Oxygen (Diatomic Element).

1 mark

A

O2

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9
Q

Give the Molecular formula of Fluorine (Diatomic Element).

1 mark

A

F2

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10
Q

Give the Molecular formula of Chlorine (Diatomic Element).

1 mark

A

Cl2

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11
Q

Give the Molecular formula of Bromine (Diatomic Element).

1 mark

A

Br2

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12
Q

Give the Molecular formula of Iodine (Diatomic Element).

1 mark

A

I2

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13
Q

Give the Molecular formula of Astatine (Diatomic Element).

1 mark

A

At2

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14
Q

Give the Diatomic Element from each of the Molecular Formulae.

H2, N2, O2, F2, Cl2, Br2, I2, At2

(8 marks)

A 
H2 - Hydrogen
N2 - Nitrogen
O2 - Oxygen
F2 - Fluorine
Cl2 - Chlorine
Br2 - Bromine
I2 - Iodine
At2 - Astatine
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15
Q

Give the Diatomic Element from the Molecular Formulae: H2

1 mark

A

Hydrogen

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16
Q

Give the Diatomic Element from the Molecular Formulae: N2

1 mark

A

Nitrogen

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17
Q

Give the Diatomic Element from the Molecular Formulae: O2

1 mark

A

Oxygen

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18
Q

Give the Diatomic Element from the Molecular Formulae: F2

1 mark

A

Fluorine

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19
Q

Give the Diatomic Element from the Molecular Formulae: Cl2

1 mark

A

Chlorine

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20
Q

Give the Diatomic Element from the Molecular Formulae: Br2

1 mark

A

Bromine

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21
Q

Give the Diatomic Element from the Molecular Formulae: I2

1 mark

A

Iodine

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22
Q

Give the Diatomic Element from the Molecular Formulae: At2

1 mark

A

Astatine

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23
Q

What are used all over the world, no matter which language is spoken?

(1 mark)

A

The same chemical symbols.

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24
Q

What does a formula do?

3 marks

A

A formula gives information about the type and the number of each atom present in a Compound.

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25
Q

What does the Formula for Sodium Sulfate (Na2SO4) tell you about what it Contains.

is Na2SO4. It tells you that sodium sulfate contains:

(3 marks)

A
  • 2 Sodium Atoms
  • 1 Sulfur Atom
  • 4 Oxygen Atoms
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26
Q

What do the Subscript Numbers refer to?

2 marks

A

The Subscript Numbers refer to the Element before them.

  • If there is just 1 Atom in the Formula a 1 is not written.
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27
Q

Sometimes a Formula includes Brackets.
How are they used?

(2 marks)

A

The Atoms inside the brackets are multiplied by the number outside the brackets.

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28
Q

Aluminium sulfate’s formula is Al2(SO4)3.

What does it contain?

(3 marks)

A
  • 2 atoms of aluminium
  • 3 atoms of sulfur
  • 12 atoms of oxygen
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29
Q

Give the Formulae for the following Compounds.

Water, Carbon Monoxide, Carbon Dioxide, Sulfur Dioxide, Sulfur Trioxide

(5 marks)

A 
Water - H20 
Carbon Monoxide - CO
Carbon Dioxide - CO2
Sulfur Dioxide - SO2
Sulfur Trioxide - SO3
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30
Q

Give the Formulae for the following Compounds.

Nitrogen Monoxide, Nitrogen Dioxide, Ammonia, Hydrochloric Acid, Nitric Acid, Sulfuric Acid.

(6 marks)

A 
Nitrogen Monoxide - NO
Nitrogen Dioxide - NO2
Ammonia - NH3
Hydrochloric Acid - HCl
Nitric Acid - HNO3
Sulfuric Acid - H2SO4
31
Q

What do Ionic Compounds contain?

2 marks

A

Positive and Negative Ions.

32
Q

In Ionic Compounds the number of positive charges must be equal to what? And why?

(4 marks)

A

The Number of Positive Charges must equal to the Number of Negative Charges, so that the Compounds has no overall charge.

  • This is because they cancel each other out.
33
Q

When the number of charges is different in 2 Ions within an Ionic Compound, what can help?

(1 mark)

A

A ‘swap and drop’ method can help.

34
Q

Explain the ‘Swap and Drop Method’.

8 marks

A
  • Write down the symbol + charge of each Ion in the Compound.
  • Ignore the sign and if the number of the charges are the same, then write the formula in a 1:1 ratio.
  • If the number of the charges is different, swap the charges by crossing sides, drop the signs and write the formula.
  • Watch out for Molecular Ions – you’ll need to use brackets if there is more than one of them.
35
Q

In a chemical reaction, what are the substances that react together called?

(1 mark)

A

The substances that react together are called Reactants.

36
Q

In a chemical reaction, what are the substances that are made called?

(1 mark)

A

The substances that are made are called products.

37
Q

All reactions can be represented in word equations, which must contain what?
Give an example.

(2 marks)

A

an arrow (→)

  • reactants → products
38
Q

Give an example of a Word Equation.

4 marks

A

When heated, green Copper(II) Carbonate decomposes into black Copper(II) Oxide and colourless Carbon Dioxide Gas.

copper(II) carbonate → copper(II) oxide + carbon dioxide

39
Q

Why do Chemical Equations contain an arrow and not an equals sign?

(1 mark)

A

The arrow means ‘reacts to make’.

40
Q

Nitrogen and Hydrogen react together to form Ammonia.

Give the word equation for the reaction.

(3 marks)

A

Nitrogen + Hydrogen → Ammonia

41
Q

No atoms are created or destroyed in a chemical reaction.
What does happen during a chemical reaction?

(3 marks)

A

The Atoms are rearranged.

- Balanced symbol equations show the original arrangements and the new ones.

42
Q

What do Balanced Symbol Equation show?

2 marks

A

Balanced Symbol Equation show the original arrangements and the new ones.

43
Q

Writing Balancing Symbol Equations

10 marks

A
  1. Check to see if there is an equal number of atoms of each element on both sides. There is not.
    - N2 + H2 → NH3
  2. There are 2 N atoms on the left but only one on the right - put a big 2 on the left of the NH3.
    - N2 + H2 → 2NH3
  3. Check again. There are 2 H atoms on the left but (2 × 3) = 6 on the right, so put a big 3 in front of the H2.
    - N2 + 3H2 → 2NH3
  4. Check again to see if there are equal numbers of each element on both sides. There is.
    - (2 N atoms and 6 H atoms)
  5. Add the state symbols if asked to do so.
    - N2(g) + 3H2(g) → 2NH3(g)
44
Q

What does a Balancing Number do?

2 marks

A

A balancing number multiplies all the atoms in the formula next to it.

  • Never change the formula of a compound to make the equation balance.
45
Q

What can you never do while Balancing Symbol Equations?

1 mark

A

Never change the formula of a compound to make the equation balance.

46
Q

Give the 4 State Symbols.

9 marks

A

(s) - solid
(l) - liquid
(g) - gas
(aq) - aqueous solution (dissolved in water)

47
Q

Where are State Symbols used?

1 mark

A

State symbols are used in Chemical Equations.

48
Q

An iron nail is placed in a solution of blue copper(II) sulfate. Over time, a brown solid appears and the solution becomes colourless. This is because copper and a solution of iron(II) sulfate forms.

Add state symbols to the balanced chemical equation for the reaction of iron with copper(II) sulfate.

Fe + CuSO4 → FeSO4 + Cu

(4 marks)

A

Fe(s) + CuSO4(aq) → FeSO4(aq)+ Cu(s)

49
Q

Give the State Symbol for a Solid.

1 mark

50
Q

Give the State Symbol for a Liquid.

1 mark

51
Q

Give the State Symbol for a Gas.

1 mark

52
Q

Give the State Symbol for an Aqueous Solution.

1 mark

53
Q

What do Ionic compounds do when they are dissolved?

1 mark

A

They react

54
Q

What Ion does not react when dissolved?

2 marks

A

Some spectator ions do not react and remain unchanged.

55
Q

Where are Spectator ions not shown?

1 mark

A

Spectator Ions are not shown in an ionic equation.

56
Q

Give the 2 different types of Ionic Equation?

2 marks

A
  • Neutralisation

- Displacement

57
Q

Describe what is Neutralisation.

5 marks

A

When an acid reacts with an alkali, the acid’s Hydrogen Ions react with the alkali’s Hydroxide Ions to produce water. The other ions are left unchanged.

58
Q

Example of Neutralisation; when hydrochloric acid (HCl) is mixed with potassium hydroxide (KOH), the Hydrogen ions (H+) react with the Hydroxide ions (OH-).

Which Ions are the spectator Ions in this Equation?

(4 marks)

A

The chloride (Cl-) and potassium (K+) ions are spectator ions.

59
Q

Example of Neutralisation; when hydrochloric acid (HCl) is mixed with potassium hydroxide (KOH), the Hydrogen ions (H+) react with the Hydroxide ions (OH-). The chloride (Cl-) and potassium (K+) ions are spectator ions.

Give the Chemical Equation for this reaction.

(6 marks)

A

H+(aq) + OH-(aq) → H2O(l)

60
Q

Describe what happens in Displacement Reactions.

4 marks

A

The More Reactive Metal displaces (takes the place of) a Less Reactive Metal from a metal compound.

61
Q

Example of a Displacement Reaction; when magnesium (Mg) reacts with copper(II) sulfate (CuSO4), the magnesium atoms react with the copper(II) ions in the copper(II) sulfate.

Name the Spectator Ions in this Equation.

(1 mark)

A

The sulfate ions are spectator ions and do not take part in the reaction.

62
Q

Example of a Displacement Reaction; when magnesium (Mg) reacts with copper(II) sulfate (CuSO4), the magnesium atoms react with the copper(II) ions in the copper(II) sulfate. The sulfate ions are spectator ions and do not take part in the reaction.

Give the Chemical Equation for this Reaction.

(8 marks)

A

Mg(s) + Cu2+(aq) → Cu(s) + Mg2+(aq)

63
Q

What happens during Neutralisation when hydrochloric acid (HCl) is mixed with potassium hydroxide (KOH)

(3 marks)

A

The Hydrogen Ions (H+) react with the Hydroxide Ions (OH-) to produce water (H20).

64
Q

What happens during a Displacement Reaction when magnesium (Mg) reacts with copper(II) sulfate (CuSO4)

(2 marks)

A

The Magnesium Atoms react with the Copper(II) Ions in the copper(II) sulfate.

65
Q

When are Half equations most often used?

2 marks

A

In redox reactions and in electrolysis.

66
Q

What do Half Equations involve?

6 marks

A

They involve either Atoms + Molecule gaining/losing Electrons to become Ions.

OR

Ions gaining or losing Electrons to become Atoms + Molecules.

67
Q

Give the process for writing a Half Equation.

5 marks

A
  • Write down the reactant + the product.
  • Balance the atoms.
  • Write the total charge underneath each species in the equation.
  • Balance the charge by adding electrons.
68
Q

Step by step write a half equation for the conversion of oxide ions into an oxygen molecule.

(8 marks)

A
  • Write down the reactant and the product. O2- → O2
  • Balance the atoms. 2O2- → O2
  • Write the total charge underneath each species in the equation. 20^2- / (-4)→ 02 / (0)
  • Balance the charge by adding electrons. 2O2- → O2 + 4e-
69
Q

What does OILRIG tell us?

6 marks

A 
Oxidation 
Is the 
Loss of electrons
Reduction 
Is the 
Gain of electrons
70
Q

What do Electrons on the right of a half Equation (after the arrow) tell us?

(2 marks)

A

They (Electrons) are being lost, this means Oxidation.

71
Q

What do Electrons on the left of a Half Equation (before the arrow) tell us?

(2 marks)

A

They (Electrons) are being gained, this means Reduction.

72
Q

Give an example of a Oxidation Equation.

5 marks

A

Na → Na ^+ + e^-

73
Q

Give an example of a Reduction Equation.

5 marks

A

Na^+ + e^- → Na

CCEA GCSE Chemistry (7 decks)

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