Pretty sure its all of the above since all of them are true
Answer:
-5.51 kJ/mol
Explanation:
Step 1: Calculate the heat required to heat the water.
We use the following expression.

where,
- c: specific heat capacity
- m: mass
- ΔT: change in the temperature
The average density of water is 1 g/mL, so 75.0 mL ≅ 75.0 g.

Step 2: Calculate the heat released by the methane
According to the law of conservation of energy, the sum of the heat released by the combustion of methane (Qc) and the heat absorbed by the water (Qw) is zero
Qc + Qw = 0
Qc = -Qw = -22.0 kJ
Step 3: Calculate the molar heat of combustion of methane.
The molar mass of methane is 16.04 g/mol. We use this data to find the molar heat of combustion of methane, considering that 22.0 kJ are released by the combustion of 64.00 g of methane.

Explanation:
Mg+O>MgO
Here the mg loses it electron and is oxidised and oxygen gains and is reduced.
Mg(2+)and O(2-)
Mg is a reducing agent it makes oxygen to be reduced while itself being oxidised and vice versa.
Gas.
The sky is not solid, not liquid but of gas. It is also
called the atmosphere, one of the important spheres on earth that influences
the climate –temperature, humidity, precipitation, atmospheric pressure, and
the biotic community as a whole. The atmosphere or the sky is composed of many
layers and is responsible to protecting the living organisms of the earth
against the deadly ultraviolet rays and other strong radiation coming from the
sun.