<span>Consider the following reaction:
2CH3OH(g)→2CH4(g)+O2(g)ΔH=+252.8kJ
Calculate the amount of heat transferred when 27.0g of CH3OH(g) is decomposed by this reaction at constant pressure.
27.0 g </span>CH3OH(g) (1 mol/ 32.05g) = 0.84 mol CH3OH(g)
ΔH =+252.8kJ = Q = 0.84 mol (252.8kJ) = 213 kJ
Among the choices, the unit of energy is calories. Answer in 1) is D. In 2) we are given with te mass , heat and temperature change. we just need to get the heat capacity and compare it with the following metals. The calculated heat capacity is 0.46 kJ/kg K. The answer is A. iron. In 3) we can compute the heat absorbed by the formula ΔH=mCpΔT. Cp of water is 4.18 J/g K. Answer of 3) is D. In 4) the formula used in Cp=ΔH/mΔT. Answer in 4) is A. The heat of enthalpy of fusion of ice is 80 cal/g. We convert this to J/g. Answer in 5) is B.334 J/g.
<span>If a neutral atom becomes negatively charged, it has undergone reduction.
Reduction is the process through which a neutral atom gain an electron (thus reducing its oxidation number) and turns into a negative ion (also known as : anion)</span>
The number of oxygen atoms are 6 atoms
<u><em>Explanation</em></u>
According to the law of mass conservation the number of reactant atoms is equal to number of product atoms.
For given equation to obey the law of mass conservation it need to be balanced as below
4 Al + 3 O₂ → 2 Al₂O₃
Al₂O₃ is the product,therefore the number of oxygen atom
= coefficient in front of Al₂O₃ × subscript of O
=2 x 3 = 6 atoms
