Answer:
Ni (s) is oxidized because it loses electrons. This makes it the reducing agent.
CuCl₂ (aq) is reduced because it gains electrons. This makes it the oxidizing agent.
Explanation:
In the reaction:
Ni(s) + CuCl₂(aq) → Cu(s) + NiCl₂(aq)
Ni (s) is oxidized because it loses electrons. This makes it the reducing agent.
------------> Ni (s) has an oxidation number of 0. All lone atoms (that are not ions) have a 0 oxidation number.
-------------> In NiCl₂ (aq), chlorine must have an oxidation number of -1, and because there are two chorine atoms, they contribute a total -2 charge. To make the overall charge neutral, nickel must have an oxidation number of +2 to balance the charges.
--------------> Because nickel goes from an oxidation number of 0 to +2, this indicates that it lost electrons and was reduced.
CuCl₂ (aq) is reduced because it gains electrons. This makes it the oxidizing agent.
-------------> In CuCl₂ (aq), chlorine must have an oxidation number of -1, and because there are two chorine atoms, they contribute a total -2 charge. To make the overall charge neutral, copper must have an oxidation number of +2 to balance the charges.
------------> Cu (s) has an oxidation number of 0. All lone atoms (that are not ions) have a 0 oxidation number.
--------------> Because copper goes from an oxidation number of +2 to 0, this indicates that it gained electrons and was oxidized.
The sample of oxygen gas was collected through water displacement. So, the gas collected will be a mixture of oxygen and water vapor.
Given that the total pressure of the mixture of gases containing oxygen and water vapor = 749 Torr
Vapor pressure of pure water at 
=25.81mmHg
= 
According to Dalton's law of partial pressures,
Total pressure = Partial pressure of Oxygen gas + Partial pressure of water
749 Torr = Partial pressure of Oxygen gas + 25.81 Torr
Partial pressure of Oxygen gas = 749 Torr - 25.81 Torr = 723.19 Torr
Therefore the partial pressure of Oxygen gas in the mixture collected will be 723.19 Torr
Harmonic melody and something else hold on...checking
