Alkanes Flashcards

All 6 cards in this deck

What is a hydrocarbon?

A compound containing hydrogen and carbon atoms only.

What are the molecular formulae of methane, ethane, propane and butane?

$\mathrm{CH_4}$, $\mathrm{C_2H_6}$, $\mathrm{C_3H_8}$, $\mathrm{C_4H_{10}}$

What is the general formula of an alkane?

$\mathrm{C_nH_{2n+2}}$

e.g. $n = 5$ gives $\mathrm{C_5H_{12}}$

Why are alkanes described as saturated hydrocarbons?

They contain hydrogen and carbon only, and all the carbon–carbon bonds are single bonds (no C=C).

What are the steps to draw the displayed structure of an alkane?

e.g. propane, $\mathrm{C_3H_8}$

1. Draw the carbon chain joined by single bonds: C–C–C
2. Add hydrogens so every carbon has 4 bonds: 3 H, 2 H, 3 H
3. Show every bond as a line, with no double bonds: $\mathrm{CH_3\!-\!CH_2\!-\!CH_3}$ with all C–H bonds drawn

True or false? $\mathrm{C_3H_6}$ is an alkane.

False. It fits $\mathrm{C_nH_{2n}}$, so it is an alkene (propene).