4936284
Description
Flashcards by Bee Brittain, updated more than 1 year ago
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Created by Bee Brittain
almost 9 years ago
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| Question | Answer |
| Draw the two types of bond in an alkane | C-C and C-H bonds All sigma bonds |
| Why are Alkenes fairly unreactive? | - They have strong C-C bonds and C-H bonds - C-C bonds are non-polar - The electronegativity of C and H is so similar the C-H bond can also be considered non-polar |
| Alkanes can take part in an exothermic reaction. What is the name of this reaction? | Combustion |
| Name the products when an alkane is burned in a plentiful supply of oxygen | - Carbon Dioxide - Water |
| Write out the word equation for the combustion of Ethane in a plentiful supply of Oxygen | Ethane + Oxygen --> Carbon Dioxide + Water |
| Write out the symbol equation for when methane reacts with oxygen in a plentiful supply of oxygen. Include State Symbols. | CH4 (g) + 2O2 (g) --> CO2 (g) + 2H2O (l) |
| Name the 3 products that can be produced when an alkane is burned in a limited supply of oxygen | Water (H2O) Carbon Monoxide (CO) Carbon (C) (solid) |
| Why is carbon dioxide hard to detect and dangerous? | It is hard to detect as it is colourless and odourless. It is dangerous because it is highly toxic. |
| Write out a symbol equation for the reaction between Heptane and oxygen in a limited supply of O2. (Include state symbols) | C7H16 (g) + 7.5O2 (g) --> 7CO (g) + 8H2O (l) |
| When an alkane reacts with a halogen, what provides the initial energy to start the reaction? | UV radiation |
| Reacting an alkane with a halogen is an example of what type of reaction? | Substitution reaction |
| Draw out the symbol equation for when methane is reacted with bromine. (1 mark for correct equation) (1 mark for correct state symbols) | CH4 (g) + Br2 (l) --> CH3Br (g) + HBr (g) |
| What is the name of the mechanism for the bromination of alkanes? | Free Radical Substitution |
| What is the first step called in the mechanism for the bromination of alkanes? | Initiation |
| The covalent bond in the bromine molecule is broken by what process? Where do the electrons go? | Homolyctic Fission One electron from the (now broken) covalent bond goes to each Bromine atom |
| What is the end product of the initiation stage? | two bromine radicals |
| Radicals don't have an electron pair, they just have one electron. What does this mean? | They are extremely reactive and unstable |
| What is the second step in free radical substitution called? | Propagation (there could be a couple of propagation steps) |
| Describe the first propagation step for the free radical substitution between bromine and methane Write a symbol equation for it | Bromine radical reacts with a C-H bond in methane to form a methyl radical (CH3') and a molecule of hydrogen bromide CH4 + Br' --> CH3Br' + HBr |
| Describe the second propagation step for the free radical substitution between bromine and methane Write an equation for it | Each methyl radical reacts with a molecule of Bromine to form bromomethane (CH3Br) and another *bromine radical (Br') *This new bromine radical means that the propagation steps can occur again and that is why it is a chain reaction CH3' + Br2 --> CH3Br + Br' |
| What is the third step of free radical substitution called? | Termination |
| What happens in the final step of free radical substitution | Two radicals react to form an element/compound with an electron pair |
| Give three examples of termination steps | Br' + Br' --> Br2 CH3' + CH3' --> C2H6 CH3' + Br' --> CH3Br |
| Methane and Ethane have only one monosubstituted product. How many does monosubstituted isomers does pentane have? | Three monosubstituted isomers. 1-bromopentane 2-bromopentane 3-bromopentane |
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