1.
Halogens and alkanes produce what
Correct Answer
A. Halogenalkanes
Explanation
Halogens and alkanes react to produce halogenalkanes. This reaction involves the substitution of a hydrogen atom in an alkane with a halogen atom. The halogenalkanes are formed as a result of the replacement of the hydrogen atom by the halogen atom. This reaction is a type of homolytic fission, where the bond between the hydrogen and carbon atoms is broken evenly, resulting in the formation of free radicals. These free radicals then combine with the halogen atoms to form the halogenalkanes.
2.
The equation to show the formation of bromomethane from methane and bromine is Br + CH4 -----CH3Br +HBr ( numbers shd all be little)
Correct Answer
A. True
Explanation
The equation provided correctly shows the formation of bromomethane from methane and bromine. In the reaction, one bromine atom (Br) reacts with one methane molecule (CH4) to form one bromomethane molecule (CH3Br) and one hydrogen bromide molecule (HBr). Therefore, the answer is true.
3.
Name the major product formed when alarge excess of bromine reacts with methane with UV light
Correct Answer
A. Tetrabromomethane
Explanation
See exam question CGP OCR p61 Q1
4.
What feature makes alkenes so useful for industry?
Correct Answer
B. More reactive
Explanation
Alkenes are more reactive compared to other compounds due to the presence of a double bond between carbon atoms. This double bond allows alkenes to undergo various chemical reactions such as addition and polymerization, making them highly versatile in industrial applications. Their reactivity enables them to be used in the production of plastics, solvents, synthetic fibers, and many other important products.
5.
Double bonds joining up is called
Correct Answer
B. Polymerisation
Explanation
Polymerisation refers to the chemical process in which monomers (small molecules) join together to form a polymer (a large molecule). In the context of the question, double bonds joining up refers to the process of multiple monomers with double bonds reacting and forming a polymer chain. Therefore, the term "polymerisation" accurately describes this process.
6.
Describe one way that polypropene can be recycled
Correct Answer
C. Melted and remoulded
Explanation
Polypropene can be recycled by melting it down and remoulding it. This process involves heating the polypropene until it reaches its melting point, then shaping it into a new form. By melting and remoulding, the polypropene can be transformed into a different product or used to create new items, reducing the need for virgin plastic production. This method of recycling helps to conserve resources, reduce waste, and minimize the environmental impact of polypropene disposal.
7.
Describe how bromine water can be used to test for one C=C double bond in an alkene
Correct Answer
B. Shake and turns colourless
Explanation
When bromine water is added to an alkene, it undergoes a reaction called addition. The orange color of bromine water is due to the presence of bromine molecules. However, when bromine reacts with the alkene, it adds across the C=C double bond, forming a colorless product. This reaction is known as bromination. Therefore, when bromine water is added to an alkene and it turns colorless, it indicates the presence of one C=C double bond in the alkene.
8.
What type of compounds do you get if you add hydrogen to alkenes?
Correct Answer
B. Alkanes
Explanation
When hydrogen is added to alkenes, a process known as hydrogenation occurs. This reaction involves the breaking of the double bond in the alkene and the addition of hydrogen atoms. The result is the formation of alkanes, which are saturated hydrocarbons. Alkanes have only single bonds between carbon atoms and are therefore more stable than alkenes. This addition reaction is commonly used in industrial processes to convert unsaturated compounds into saturated ones.
9.
The general formula for alcohols is C n H 2n OH true or false?
Correct Answer
B. False
Explanation
it is C n H 2n+1 OH