Propane, C3H8\text{C}_3\text{H}_8C3H8, is an alkane.
Propane undergoes complete combustion in oxygen. Carbon dioxide and water are made.
Write the balanced symbol equation for the complete combustion of propane.
The table shows the energy given out when 1 g of different alkanes burn.
| Alkane | Number of carbon atoms | Energy given out (kJ\text{kJ}kJ) |
|---|---|---|
| methane | 1 | 55.6 |
| ethane | 2 | 52.0 |
| propane | 3 | [missing] |
| butane | 4 | 49.6 |
| pentane | 5 | 48.7 |
| hexane | 6 | 48.4 |
Plot a graph of the data from the table onto the axes provided below.

Draw a curve of best fit on your graph.
The energy given out when 1 g of propane burns is missing from the table. Use your graph to estimate the energy given out by propane.
What name is given to the type of reaction that gives out energy?
Complete the displayed formula of propane, C3H8\text{C}_3\text{H}_8C3H8, showing all atoms and covalent bonds.
Combustion of fuels releases carbon dioxide gas into the atmosphere.
State an environmental problem caused by increased levels of carbon dioxide gas in the atmosphere.
Explain one way this environmental problem can be reduced.