Chemistry Revision: Symbols, Formulae and Equations

Flashcards for Chemistry revision on symbols, formulae and equations

What is the formula for Calcium nitrate?

Ca(NO3)2

How many Calcium (Ca) atoms are in Calcium nitrate (Ca(NO3)2)?

One

What does the number '2' after the brackets in a formula like Ca(NO3)2 do?

Doubles everything inside the brackets.

In Ca(NO3)2, how many Nitrogen (N) and Oxygen (O) atoms are there?

2 N and 6 O

What are the steps to write formulae?

Write out the two elements involved, write out the combining numbers, draw an 'X' beneath, carry the number of charges down, and read vertically down.

What is the formula of Sodium Chloride (Na+ and Cl-)?

NaCl

What is the formula of Magnesium Bromide (Mg2+ and Br-)?

MgBr₂

What is the formula of Aluminum Oxide (Al3+ and O2-)?

Al₂O₃

If there is more than one group present in a compound's formula, what must be used?

Brackets

What is the formula for Copper (II) sulphate?

CuSO₄

What is the formula for Magnesium hydroxide?

Mg(OH)₂

What is the formula for Ammonium sulphate?

(NH₄)₂SO₄

What is the formula for Hydrochloric acid?

HCl

What is the formula for Sulphuric acid?

H₂SO₄

What is the formula for Nitric acid?

HNO₃

What is the formula for Methane?

CH₄

Give examples of Halogens formulae.

Cl₂, I₂

What is the formula for Sodium hydroxide?

NaOH

What is the formula for Ammonia?

NH₃

How to balance an equation?

Put big numbers IN FRONT of each compound

Balance the following equation: Mg + HCl → MgCl₂ + H₂

Mg + 2HCl → MgCl₂ + H₂

What state symbol represents 'Solid'?

(s)

What state symbol represents 'Liquid'?

(l)

What state symbol represents 'Gas'?

(g)

What state symbol represents 'Aqueous'?

(aq)

What are the steps to write ionic equations?

Write out the ions, put aline through spectator ions, and rewrite the equation

What are spectator ions?

Ions that haven't changed during the reaction.

What is the net ionic equation for the reaction between any strong acid and base?

H⁺(aq) + OH⁻(aq) → H₂O(l)

What is the net ionic equation for the reaction between copper sulphate and sodium hydroxide?

Cu²⁺(aq) + 2OH⁻(aq) → Cu(OH)₂(s)

Which type of equation involves electrons (e⁻)?

Half Equations

What is the half equation for Mg in the reaction of magnesium and copper sulphate?

Mg → Mg²⁺ + 2e⁻

What is the half equation for Cu in the reaction of magnesium and copper sulphate?

Cu²⁺ + 2e⁻ → Cu