Fire & Fuels: what we are learning

1) I can explain the products of combustion and how to test for them

2) I can explain the difference between complete combustion and incomplete combustion

Wednesday, April 19, 2023

What is produced when a candle burns?

Get your equipment: candle, small beaker, limewater, piece of cobalt chloride paper, safety glasses

1. Light a candle & place a small beaker above it.

2. Control the amount of O2 getting to the flame

3. What do you see?

4. What happens to the colour of the flame?

What is produced when a candle burns?

1. Lower the beaker over the candle.

2. When the candle goes out, slightly lift a side of the beaker and quickly wipe a piece of dry blue cobalt chloride paper around the sides of the beaker.

3. What do you see?

4. What does your result tell you?

What is produced when a candle burns?

1. Put the beaker upright and quickly squirt a some limewater in before all the gas escapes.

2. Swirl the beaker quite hard, but don’t spilling it!

3. What do you see?

4. What does your result tell you?

Copy some notes from the board...

What are some examples of incomplete combustion?

1. Bunsen burner with air hole closed2. Starting a wood fire or bbq3. Turning a log-burner down low overnight4. Engines or boilers that have not been serviced

Why is incomplete combustion a nuisance?

1. Soot (carbon) makes things dirty2. Soot can irritate the lungs and cause respiratory disease3. Smog in Christchurch4. Carbon monoxide is poisonous because... ... it prevents oxygen binding to haemoglobin in your blood5. CO is particularly dangerous because it is colourless and odourless (can’t smell it)

Think – Pair – Share:

Video clip: Fire Power!

then Worksheet

1) House Fires

2) Fire Extinguishers

Teacher Demo: the products of burning

Copy the diagram

Explain what is happening at A, B and C

What is formed in test tube X and Y?

What is the test for the products in test tubes X and Y?