The answer is either A or C. Sorry I'm not much help :)
Answer:
C = Electrons are won and lost.
Explanation:
The oxidation reduction reactions are called redox reaction. These reactions are take place by gaining and losing the electrons and oxidation state of elements are changed.
Oxidation:
Oxidation involve the removal of electrons and oxidation state of atom of an element is increased.
Reduction:
Reduction involve the gain of electron and oxidation number is decreased.
Consider the following reactions.
4KI + 2CuCl₂ → 2CuI + I₂ + 4KCl
the oxidation state of copper is changed from +2 to +1 so copper get reduced.
CO + H₂O → CO₂ + H₂
the oxidation state of carbon is +2 on reactant side and on product side it becomes +4 so carbon get oxidized.
Na₂CO₃ + H₃PO₄ → Na₂HPO₄ + CO₂ + H₂O
The oxidation state of carbon on reactant side is +4. while on product side is also +4 so it neither oxidized nor reduced.
H₂S + 2NaOH → Na₂S + 2H₂O
The oxidation sate of sulfur is -2 on reactant side and in product side it is also -2 so it neither oxidized nor reduced.
Oxidizing agents:
Oxidizing agents oxidize the other elements and itself gets reduced.
Reducing agents:
Reducing agents reduced the other element are it self gets oxidized.
The answer is B.) Energy directly from the sun to both producers and consumers.
Answer: 90 g O2
Explanation: soution attached:
Balance first the chemical equation
CH4 + O2 => CO2 +2H2O
Convert mass of CH4 to moles
Use the mole ratio of CH4 and O2 from the balanced equation.
Convert moles of O2 to mass using the molar mass of O2.
Answer : The order of increasing standard molar entropy is:

Explanation :
Entropy : It is defined as the measurement of randomness or disorderedness in a system.
The order of entropy will be,
As we are moving from solid state to liquid state to gaseous state, the entropy will be increases due to the increase in the disorderedness.
As we are moving from gaseous state to liquid state to solid state, the entropy will be decreases due to the decrease in the disorderedness.
From this we conclude that the solids have less disorder in the system than liquids because the molecules in the solid are closely or tightly packed as compared to liquid.
The liquids have less disorder in the system than gases because the molecules in the liquid are more close as compared to gases.
That means the more disorderedness in a system, the more will be the entropy.
So, the order of increasing standard molar entropy is:
