1. How can you qualitatively determine which type of compound you have when you are presented with ethanol and ethane, and how does this work? All we learned in school is that Br2 changes colors from brown to clear when it bonds with a compound- but this only works for alkene since it has a C=C double bond? So how could we do this?
2. Why does Ethyne and Ethene have a lower boiling point than Ethane? I thought that they would have higher boiling points due to the double/triple bond which should make them stronger
2. Why does Ethyne and Ethene have a lower boiling point than Ethane? I thought that they would have higher boiling points due to the double/triple bond which should make them stronger
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1. Alcohols are liquids, alkanes are gases.
2. Bonding INSIDE the molecule (INTRAmolecular forces) has no effect on bp. Its the forces BETWEEN the molecules you need to look at (INTERmolecular forces). In this case these are Van der Waals' forces. These forces increase with RMM (molar mass), so ethane (RMM = 30) has the highest bp, ethyne (RMM = 26) the lowest.
2. Bonding INSIDE the molecule (INTRAmolecular forces) has no effect on bp. Its the forces BETWEEN the molecules you need to look at (INTERmolecular forces). In this case these are Van der Waals' forces. These forces increase with RMM (molar mass), so ethane (RMM = 30) has the highest bp, ethyne (RMM = 26) the lowest.
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Think of it like this... Double bonds have a strong bond between the atoms but have a weak structure. So triple bonds hae an even stronger bond but weaker structure