Lab 6

In general, when hydrocarbons like oil are added to water, the two liquids do not mix because hydrocarbons are non-polar and water is polar.

Hydrocarbons and water generally do not mix. The hydrocarbons are not soluble in water because they are non-polar and water is polar.

In general, when a hydrocarbon is added to water, the hydrocarbon will float above the water because hydrocarbons are less dense than water.

Hydrocarbons are generally less dense than water so they float on top, like the example of oil on water.

Are hydrocarbons soluble or insoluble in water? Give a brief explanation.

Hydrocarbons are insoluble in water because they are non-polar and water is polar.

The biggest concern of working with hydrocarbons in lab is that many of them are flammable. Therefore, hydrocarbons should be handled in the hood to contain any associated vapors with that hazard.

Hydrocarbons are made from carbons and hydrogen and can be gases, liquids, or solids. The hazard that many of them have in common is flammability. Even the liquids or solids often give off vapors that are flammable. Because so many hydrocarbons have hazardous associated vapors, they should be handled in the fume hood.

Determine whether or not each hydrocarbon is saturated.

Saturated compounds have as many hydrogens around each carbon as possible, which is achieved by only having single bonds present. Thus, the two structures that only have single bonds are saturated. The two structures with multiple bonds, a double bond and triple bond respectively, are unsaturated hydrocarbons.

How many grams of acetylene would be given off if the limiting reagent in the reaction is calcium carbide and you start with 2.00 g? fw CaC2 = 64.1 g/mol fw C2H2 = 26.0 g/mol

0.8112 g

Identify the type of hydrocarbon represented by each structure.

- Hydrocarbons are usually classified by the highest order of bond present. - Alkanes only have single bonds, whether in a linear or cyclic formation. Alkanes in a ring formation are often called cycloalkanes. - Alkenes have at least one double bond. Cyclic alkene structures can specifically be called cycloalkenes. - Alkynes have at least one triple bond. Cyclic alkynes generally do not exist because of the linear arrangement around the bond. - Aromatic compounds have specific requirements. An aromatic hydrocarbon has carbons in a ring and alternating single and double bonds, which create stability through the delocalization of the electrons. The most common aromatic ring size is six carbons but others do exist.

A hydrocarbon is saturated if only _____ are present. _____ are saturated hydrocarbons. A hydrocarbon is unsaturated if any _____ are present. _____ are unsaturated hydrocarbons.

A hydrocarbon is saturated if only single bonds are present. Alkanes are saturated hydrocarbons. A hydrocarbon is unsaturated if any multiple bonds are present. Alkenes are unsaturated hydrocarbons.

Baeyer's test, also known as the permanganate test, shows the presence of alkenes. A positive Baeyer's test appears as a brown precipitate. A negative Baeyer's test appears as a purple solution.

Baeyer's test indicates the presence of alkenes and alkynes through their formation of manganese(IV) oxide when reacting with potassium permanganate in solution. If an alkene or alkyne is present, the brown precipitate of manganese(IV) oxide forms. If no alkenes or alkynes are present, the solution remains the purple color of the potassium permanganate.

Write the balanced equation for calcium carbide (CaC2 ) reacting with water to give off ethyne (acetylene) when reacted with water. You should be able to figure out the other product in this reaction.

CaC2(s) + 2H2O(g) → Ca(OH)2(s) + C2H2(g)

The bromine test shows the presence of alkynes. A positive bromine test appears as a colorless solution. A negative bromine test appears as an orange solution.

The bromine test indicates the presence of alkenes and alkynes through their reaction with bromine. If an alkene or alkyne is present, the solution becomes colorless as bromine is added across the double or triple bond. If no alkenes or alkynes are present, the solution remains the brownish orange color of bromine.

Which hydrocarbon group is the least reactive, why?

The least reactive hydrocarbons are alkanes because they only contain carbons and hydrogens. Additionally, alkanes don't have a forced constrain like the alkenes do. Because alkenes have double bonds, they have like a constrain on them. That is why alkenes are more reactive. Alkanes don't have that constrain and they are happy, simple, and stable molecules.