WATER + MILO MILO WATER

FLOUR + WATER + PRAWN PRAWN “CUCUR”

SYRAP + LIME + WATER LIME SYRAP

BREAD + JELLY + PEANUT BUTTER PEANUT BUTTER AND JELLY BREAD

CARBON + OXYGEN CARBON DIOXIDE

MAGNESIUM + SULPHURIC ACID MAGNESIUM SULPHATE + HYDROGEN

MAGNESIUM + HYDROCLORIC ACID MAGNESIUM OXIDE + HYDROGEN

HYDROGEN + NITROGEN AMMONIA

ALUMINIUM + IRON (III) OXIDE ALUMINIUM OXIDE + IRON

SILVER NITRATE + CALCIUM CHLORIDE SILVER CHLORIDE + CALCIUM NITRATE

CHEMICALEQUATION

• Chemical equation is a way of representing a chemical reaction.

• It shows the starting substances (reactants) and the new substances formed (products).

• There are 2 types of equations:– Word equation: uses words– Chemical equation: uses symbols and formulae

reactant + reactant product(s)

Can you identify which one is the reactant and which one is the product

1. water + milo milo water

reactant product

2. flour + water + prawn prawn “cucur”

reactant product

3. syrap + lime + water lime syrap

reactant product

4. CARBON + OXYGEN CARBON DIOXIDE

reactant product

5. MAGNESIUM + SULPHURIC ACID MAGNESIUM SULPHATE + HYDROGEN

reactant

product

Writing Chemical Equations

• Chemical equations have the same number of atoms of each element on both sides of the equation.– No atoms are created or destroyed during a

reaction. They are only rearranged.– Therefore, the number of atoms on both sides of

the equation must be equal.

• Sometimes, state symbols are shown. There are 4 state symbols:– solid (s)– liquid (l)– gas (g)– aqueous (aq)

dissolved

Reacting Hydrogen and Oxygen

Step 1: Write the word equation

Step 2: Write the chemical equation

hydrogen + oxygen water

H2 + O2 H2O

Reacting Hydrogen and Oxygen

Step 3: Check if the equation is balanced.H2 + O2 H2O

H – 2O – 2

H – 2O – 1

H2 + O2 2H2O

H – 2O – 2

H – 4O – 2

2H2 + O2 2H2O

H – 4O – 2

H – 4O – 2

Step 4 : Put in physical state or symbol that appropriate

2H2(g) + O2(g) 2H2O(l)

Test yourself

1. Potassium is burnt completely in the air to produce potassium oxide

2. Dehydration of hydrated copper (II) sulphate into copper sulphate and water

3. Zinc sulphate is decomposes when heated to produce zinc oxide and sulphur trioxide

Chemical Equation

Qualitative aspect Quantitative aspect

product reactant

Physical state

Number of mole

Can you interpret these chemical equation

1. 2KI (aq) + Br2(aq) I2(aq) + 2KBr (aq)

2. 3CuO (s) + 2Al (s) Al2O3(s) + 3Cu (s)

3. CaCO3 (s) ∆ CaO (s) + CO2 (g)

4. 2H2O2 (l) 2H2O (l) + O2(g)

5. 4CuO (s) + CH4 (g) 4Cu (s) + CO2(g) + 2H2O (l)

Can you do it????

25.0 gram of hydrated copper (II) sulphate crystal is heated according to the following formula CuSO4.5H2O CuSO4 + 5H2O

What is the mass of the dehydrated copper (II) sulphate that is formed??