Melting Points of Alkanes

The video discusses the melting points of alkanes, listing values for methane to decane. It highlights a general trend where melting points increase with molecular weight, but notes unusual features for the first three alkanes. The video also explains the odd-even effect, where melting points increase significantly when moving from an odd to an even number of carbon atoms, and less so in the reverse. The trend levels off as the chain lengthens.

What is the melting point of methane?

• -83°C

• -188°C

• -138°C

• -182°C

Which alkane has a melting point of -130°C?

• Butane

• Pentane

• Hexane

• Heptane

How does the melting point trend of alkanes compare to their boiling point trend?

• Melting point decreases while boiling point increases

• Both increase with molecular weight

• Melting point is constant while boiling point increases

• Both decrease with molecular weight

What is unusual about the melting points of the first three alkanes?

• They all have the same melting point

• The melting point increases with each alkane

• The melting point decreases from methane to propane

• They have no melting point

Which alkane has the lowest melting point among the first three?

• Methane

• Butane

• Ethane

• Propane

What happens to the melting point when moving from propane to butane?

• It decreases significantly

• It remains the same

• It increases significantly

• It decreases slightly

What is the change in melting point when moving from pentane to hexane?

• 34°C

• 21°C

• 8°C

• 45°C

What is the trend in melting point changes as the carbon chain lengthens?

• The increase becomes smaller

• The increase becomes unpredictable

• The increase becomes larger

• The increase remains constant

What is the increase in melting point when moving from nonane to decane?

• 34°C

• 21°C

• 6°C

• 50°C

What is the general trend of melting points as more carbon atoms are added to the chain?

• The melting point decreases

• The melting point remains constant

• The melting point increases

• The melting point fluctuates