1.
Bromine reacts with propane in a radical substitution reaction. Below, detail the 3 stages of this reaction and write the equations for each stage.
2.
Dichloromethane can be made by reacting methane with chlorine. Another substance is produced in the process. What is this substance?
Explanation
When methane reacts with chlorine, the resulting substance is dichloromethane (CH2Cl2). However, another substance is also produced in the process, which is hydrogen chloride (HCl). Therefore, the correct answer is HCl or hydrogen chloride.
3.
Which of the following is an alkane?
Correct Answer(s)
C. CH4
E. C60H122
Explanation
An alkane is a hydrocarbon with only single bonds between carbon atoms. CH4 is the correct answer because it is a hydrocarbon with one carbon atom and only single bonds. C60H122 is not an alkane because it contains multiple carbon-carbon double bonds, making it an alkene.
4.
Which one of the following can differentiate ethane from ethene?
Correct Answer
B. Aqueous bromine
Explanation
Aqueous bromine can differentiate ethane from ethene because ethane is saturated and does not react with bromine, while ethene is unsaturated and reacts with bromine to form a colorless solution.
5.
Methane is used as a fuel. What property is essential for this use?
Correct Answer
A. It burns exothermically
Explanation
The property that is essential for methane to be used as a fuel is its ability to burn exothermically. This means that when methane reacts with oxygen, it releases heat energy, making it an ideal fuel for combustion processes.
6.
Which one of these equations does not represent an addition reaction?
Correct Answer
A. CH2Cl2+Cl2-->CHCl3+HCl
Explanation
The equation CH2Cl2+Cl2-->CHCl3+HCl does not represent an addition reaction because no new bond is formed between the reactants. Instead, a substitution reaction occurs where a chlorine atom is substituted for a hydrogen atom in CH2Cl2.
7.
Octane is an alkane found in petrol. Which statement is true about octane?
Correct Answer
D. It reacts with chlorine by substitution
Explanation
Octane reacts with chlorine by substitution. This means that one or more hydrogen atoms in octane are replaced by chlorine atoms when they come into contact with each other. This reaction is known as chlorination and is commonly used in the production of chlorinated solvents and other industrial processes.
8.
Balance the equation:
_CH4 + _O2 --> _CO2 + _H2O
enter your answer like this: x,x,x,x
Correct Answer
1, 2, 1, 2
Explanation
The balanced equation for the given reaction is CH4 + 2O2 --> CO2 + 2H2O. This is because there is one carbon atom on both sides of the equation, four hydrogen atoms on both sides, and two oxygen atoms on both sides. By adding a coefficient of 2 in front of O2 and H2O, the equation is balanced in terms of both mass and atoms.
9.
When octane, an alkane present in petrol, is completely burnt, what are the products?
Correct Answer(s)
A. Carbon dioxide
D. Water
Explanation
When octane, an alkane present in petrol, is completely burnt, it undergoes combustion and reacts with oxygen to produce carbon dioxide and water. This is a balanced chemical equation for the combustion of octane: C8H18 + 12.5O2 → 8CO2 + 9H2O. Therefore, the products of the complete combustion of octane are carbon dioxide and water.
10.
A 10cm^3 sample of gaseous hydrocarbon is completely burnt in oxygen. The total volume of the products is 70cm^3. Which equation represents the combustion?
Correct Answer
B. C3H8(g)+5O2(g)-->3CO2(g)+4H2O(g)
Explanation
The given question states that a 10cm^3 sample of gaseous hydrocarbon is completely burnt in oxygen, resulting in a total volume of 70cm^3 for the products. The equation that represents this combustion must have a hydrocarbon reactant and products that account for the increase in volume. Among the given options, the equation C3H8(g) + 5O2(g) -> 3CO2(g) + 4H2O(g) fits this criteria. This equation shows the combustion of propane (C3H8), which has a molar volume of 22.4 L/mol. The reactants and products in this equation result in a total volume of 70cm^3, indicating that it is the correct equation for the combustion.
11.
Correct Answer
aldehyde
12.
Correct Answer
ketone
13.
Correct Answer
carboxylic acid
14.
Ethanol is an example of a......
Correct Answer
A. Primary alcohol
Explanation
Ethanol is classified as a primary alcohol because it has one carbon atom bonded to the hydroxyl group (-OH). In primary alcohols, the hydroxyl group is attached to a carbon atom that is bonded to only one other carbon atom. This distinguishes it from secondary alcohols, which have the hydroxyl group attached to a carbon atom bonded to two other carbon atoms, and tertiary alcohols, which have the hydroxyl group attached to a carbon atom bonded to three other carbon atoms. Ketones, on the other hand, do not have a hydroxyl group and are not classified as alcohols.
15.
What method can be used to obtain ethene from alkanes?
Correct Answer
D. Cracking
Explanation
Cracking is the process used to obtain ethene from alkanes. It involves breaking down larger hydrocarbon molecules into smaller ones by applying heat and pressure. This process is commonly used in the petroleum industry to produce ethene, which is an important raw material for the production of plastics and other chemicals. Distillation is a separation technique used to separate different components of a mixture based on their boiling points. Polymerisation is a process of combining monomers to form a polymer. Dehydrogenation is the removal of hydrogen from a molecule.