The answer that h are looking for is c
Answer:
Fe(s) → Fe²⁺(aq) + 2e⁻ OXIDATION
Mg²⁺(aq) + 2e⁻ → Mg(s) REDUCTION
Explanation:
The redox reaction is: MgCl₂(aq) + Fe(s) → FeCl₂(aq) + Mg(s)
We need to know that elements in ground state have 0 as the oxidation state.
Iron in the reactants, and Mg in the products
In the magnessium chloride, the Mg acts with+2, so the oxidation state has decreased → REDUCTION
In the iron(II) chloride, the Fe acts with +2, so the oxidation statehas increased → OXIDATION
The half reactions are:
Fe(s) → Fe²⁺(aq) + 2e⁻ OXIDATION
Mg²⁺(aq) + 2e⁻ → Mg(s) REDUCTION
The observation in the illustration remains in accordance with the law of conservation of mass assuming that moisture is present in the container.
<h3>What is the law of conservation of mass?</h3>
The law state that mass can neither be created nor destroyed. However, mass can be converted from one form to another.
In this case, the ion was placed in a container of pure oxygen. Assuming that moisture is present, iron reacts with oxygen to form rust according to the following equation:

The rust formed will weigh more than the initial weight of the iron.
Without the presence of moisture, one can effectively conclude that the observation violates the law of conservation of mass.
More on the law of conservation of mass can be found here: brainly.com/question/13383562
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Answer:
a) 
b) 1657 €
Explanation:
Hola,
a) En este problema, vamos a considerar el millón de litros de agua anuales, ya que con ellos podemos calcular el calor requerido para dicho calentamiento, sabiendo que la densidad del agua es de 1 kg/L:

Luego, usamos la entalpía de combustión del metano para calcular su requerimiento en kilogramos, sabiendo que la energía ganada por el agua, es perdida por el metano:


b) En este caso, consideramos que a condiciones normales de 1 bar y 273 K, 1 metro cúbico de metano cuesta 0,45 €, con esto, calculamos las moles de metano a dichas condiciones:

Con ello, los kilogramos de metano que cuestan 0,45 €:

Luego, aplicamos la regla de tres:
0.715 kg ⇒ 0.45 €
2630 kg ⇒ X
X = (2630 kg x 0.45 €) / 0.715 kg
X = 1657 €
Regards.