A student places a 2.0 gram sample of magnesium metal in a bottle and fits the bottle with a two hole rubber stopper as shown in
the diagram. Hydrochloric acid is added to the bottle and a
reaction occurs. As the reaction proceeds hydrogen gas travels through the tubing to an inverted
bottle filled with water, displacing some of the water in the bottle.
1. Calculate the number of grams of magnesium the students should mass out, to make 0.40 Liters of Hydrogrm gas at STP, show set up
reaction occurs. As the reaction proceeds hydrogen gas travels through the tubing to an inverted
bottle filled with water, displacing some of the water in the bottle.
1. Calculate the number of grams of magnesium the students should mass out, to make 0.40 Liters of Hydrogrm gas at STP, show set up
1 answer:
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Answer:
-1.78 V
Explanation:
There are several rules required to calculate the cell potential:
- given standard cell potential, we may reverse the equation: the products of a given reaction become our reactants, while reactants become our products in the reversed equation. For a reversed equation, we change the sign of the cell potential to the opposite sign;
- if we multiply the whole equation by some number, this doesn't influence the cell potential value. It only produces a different expression in the equilibrium constant.
That said, notice that the initial reaction with respect to the final reaction is:
- reversed: chromium(III) cation and chloride anion become our reactants as opposed to the products in the initial reaction, so we change the sign of the cell potential to a negative value of -1.78 V;
- each coefficient is multiplied by a fraction of
. It doesn't influence the value of the cell potential.
Thus, we have a cell of E = -1.78 V.