| difference between physical and chemical properties | physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance.
chemical property is describes the ability of a substance to undergo a specific chemical change (transforms into different substance) |
| hydrocarbons | of all organic compounds simplest types
contain only hydrogen and carbon atoms |
| 3 means of classification of hydrocarbons | 1. based on the way their carbon atoms are connected
2. depends on the type of bond between carbons
3. a class of cyclic hydrocarbons that contain a closed loop (sextet) of electrons called aromatic |
| explain more about 1st classification of them | dividing into two main groups, chain aliphatic hydrocarbons and cyclic hydrocarbons |
| explain more about 2nd classifiation | we have saturated molecules (alkanes) and unsaturated (alkenes and alkynes) |
| difference between saturated and unsaturated | Saturated fatty acids lack double bonds between the individual carbon atoms,
while in unsaturated fatty acids there is at least one double bond in the fatty acid chain. |
| some of the observed physical properties of hydrocarbons results how | from nonpolar character of the compounds |
| do hydrocarbons mix with polar solvents such as water and ethanol? | no, they do not mix |
| do hydrocarbons mix with nonpolar solvents such as ligroin | yes but relatively |
| do hydrocarbons have higher or less density than water | the density of most hydrocarbons is less than that of water they will float |
| how do hydrocarbons is determined by the type of bond between carbons present in the compound | by the chemical reactivity |
| differences between saturated and unsaturated hydrocarbons | saturated hydrocarbons (alkanes) will burn (undergo combustion)
they are generally unreactive to most reagents. They will undergo a substitution reaction with halogens, but only if exposed to ultraviolet light.
Unsaturated hydrocarbons, alkenes and alkynes, not only burn, but also react by addition of reagents to the double or triple bonds. |
| explain what will happen for aromatic compounds and non aromatic | aromatic compounds have higher carbon-to-hydrogen ratio than non-aromatic compounds, burn with a sooty flame as a result of unburned carbon particles being present.
These compounds undergo substitution in the presence of catalysts rather than an addition reaction. |
| what is the major component in "natural gas" | hydrocarbon methane |
| what are propane and butane used for | heating or cooking |
| what are the products from combustion | are carbon dioxide and water and also heat is evolved |
| Reaction with concentrated sulfuric acid for alkenes | Alkenes react with cold concentrated sulfuric acid by addition |
| Reaction with concentrated sulfuric acid for alkyl sulfonic acid | form as products and are soluble in H2SO4. |
| are saturated hydrocarbons reactive? | are unreactive (additions are not possible) |
| are alkynes reactive | yes but react slowly and require a catalyst (HgSO4) |
| are aromatic compounds reactive | unreactive since addition reactions are difficult. |
| Dilute or alkaline solutions of KMnO4 oxidize which compounds | unsaturated compounds |
| write the evidence that a reaction occurred with potassium permanganate | by the loss of the purple color of KMnO4 and the formation of the brown precipitate manganese dioxide, MnO2. |
| are there any density when hydrocarbons react with petroleum ether | no none of them has a density |
| which of hydrocarbon with the reaction of H2SO4 had a reaction | cyclohexane |
| among hydrocarbons in experiment which one burnt for short time | hexane |
| among hydrocarbons in experiment which one burnt for long time and produced charm | toluene |
| among hydrocarbons in experiment which one burnt for long time | cyclohexene |
