1.
The electrochemical series shows equations representing reactions of which type?
Correct Answer
B. Reduction
Explanation
The electrochemical series shows equations representing reactions of the reduction type. This series arranges elements and compounds in order of their ability to undergo reduction reactions. In these reactions, electrons are gained, and the species is reduced. The series helps in predicting the feasibility and direction of redox reactions by comparing the reduction potentials of different substances.
2.
Which of the following metals is highest in the electrochemical series?
Correct Answer
B. Magnesium
Explanation
Magnesium is the metal that is highest in the electrochemical series. The electrochemical series is a list of metals arranged in order of their tendency to lose electrons and form positive ions. The higher a metal is in the series, the more easily it loses electrons and the more reactive it is. Magnesium is higher in the series compared to tin, iron, and zinc, indicating that it has a greater tendency to lose electrons and is more reactive than these metals.
3.
If a cell is set up with copper and one other metal, which other metal would allow a flow of electrons AWAY FROM the copper?
Correct Answer
C. Gold
Explanation
Gold would allow a flow of electrons away from copper because gold has a lower electronegativity than copper. Electronegativity is a measure of an atom's ability to attract electrons in a chemical bond. Since gold has a lower electronegativity, it has a weaker attraction for electrons compared to copper. This means that when a cell is set up with copper and gold, the electrons will tend to flow from the copper electrode towards the gold electrode.
4.
In a cell, what type of charged particle flows in the wires?
Correct Answer
D. Electrons
Explanation
Electrons are the charged particles that flow in the wires of a cell. In a cell, the flow of electrons creates an electric current. Electrons are negatively charged and are responsible for carrying the charge from one point to another within the circuit. This movement of electrons is what allows electrical devices to function properly, as they provide the necessary energy for the circuit to work. Therefore, electrons are the correct answer to the question.
5.
In a half cell involving copper and nickel, which of the following chemicals could be used as an electrolyte for the copper electrode?
Correct Answer
C. Copper chloride solution
Explanation
Copper chloride solution could be used as an electrolyte for the copper electrode in a half cell involving copper and nickel because it contains copper ions, which can be reduced at the cathode (copper electrode) during the electrolysis process. The copper ions will gain electrons and form solid copper, while the chloride ions in the solution will migrate to the anode (nickel electrode) to balance the charge. This allows for the flow of electric current in the cell.
6.
Which of the following describes an oxidation reaction?
Correct Answer
D. Magnesium atoms losing electrons
Explanation
The process in which magnesium atoms lose electrons is an oxidation reaction. In oxidation, a substance loses electrons, and the oxidation number of the element increases. In the case of magnesium atoms losing electrons, they become magnesium ions.
7.
Which of the following statements best describes the flow of electrons in the above circuit?
Correct Answer
D. From zinc to lead through the wires
Explanation
The flow of electrons in the above circuit is from zinc to lead through the wires. This is because in a battery, the anode (negative terminal) is made of zinc and the cathode (positive terminal) is made of lead. During the chemical reaction inside the battery, zinc atoms lose electrons and become positively charged ions, while lead ions gain electrons and become neutral lead atoms. The electrons flow from the zinc electrode to the lead electrode through the wires, creating an electric current.
8.
Which of the following chemicals could NOT be used as an electrolyte in a cell?
Correct Answer
B. Calcium carbonate
Explanation
Calcium carbonate cannot be used as an electrolyte in a cell because it is an insoluble compound. Electrolytes are substances that can conduct electricity when dissolved in a solution or melted. Calcium carbonate does not dissociate into ions in water, so it cannot carry an electric current. On the other hand, ammonium chloride, sodium nitrate, and copper(II) chloride are all soluble compounds that can dissociate into ions and therefore can be used as electrolytes in a cell.
9.
Which of the following statements describe a redox reaction?
Correct Answer
B. Magnesium being added to dilute nitric acid
Explanation
When magnesium is added to dilute nitric acid, a redox reaction occurs. In this reaction, magnesium is oxidized to magnesium ions, while nitric acid is reduced to nitrogen dioxide gas. This can be seen by the change in oxidation states of the elements involved. Magnesium goes from an oxidation state of 0 to +2, indicating oxidation, while nitrogen in nitric acid goes from +5 to +4, indicating reduction. Therefore, this reaction is an example of a redox reaction.
10.
When zinc is added to copper(II) sulphate solution, what could you expect to see happening?
Correct Answer
C. The colour of the solution will fade and a brown solid will form
Explanation
When zinc is added to copper(II) sulphate solution, a displacement reaction occurs. Zinc is more reactive than copper, so it displaces copper from the copper(II) sulphate solution. This results in the formation of a brown solid called copper(I) oxide and the fading of the blue color of the solution. Therefore, the correct answer is that the color of the solution will fade and a brown solid will form.