# Combination Reactions

11SCI - Chemical Reactions

2020

## Mahi Tuatahi

1. Write down the general reaction for a displacement reaction
2. What might you observe if a displacement reaction has occurred?
3. How do you know/how can you predict if a displacement reaction will occur?
4. A piece of lead is placed into a silver iodide solution. Will a reaction occur?
• If it will, write a word and symbol equation for it.
5. A piece of aluminium is placed into a magnesium sulfate solution. Will a reaction occur?
• If it will, write a word and symbol equation for it.

## Ngā Whāinga Ako

• To describe what happens in a combination reaction.

## Combination (Synthesis) Reactions

[ \begin{aligned} A + B \longrightarrow AB \end{aligned}

]

A reaction, usually combustion, where two ions are combined to form a compound.

### Tauria Tahi

A piece of magnesium is burned over a bunsen burner and a white solid is formed.

1. What is the solid that is formed?
2. Write a word equation.
3. Write a symbol equation (with states) and balance it.
1. magnesium + oxygen gas $$\longrightarrow$$ magnesium oxide
2. $$Mg_{s} + O_{2g} \longrightarrow MgO_{s}$$
3. $$2Mg_{s} + O_{2g} \longrightarrow 2MgO_{s}$$

### Tauria Rua

Hydrogen is collected and combusted using Bunsen burner (pop test).

1. What is formed in the reaction?
2. Write a word equation.
3. Write a symbol equation (with states) and balance it.
1. hydrogen gas + oxygen gas $$\longrightarrow$$ water
2. $$H_{2g} + O_{2g} \longrightarrow H_{2}O_{g}$$
3. $$2H_{2g} + O_{2g} \longrightarrow 2H_{2}O_{g}$$