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1. which of the following is an essential condition for a redox reaction?

the reactants should be two elements.
the reactants should be two compounds.
the oxidation state of all the atoms should change.
the oxidation state of at least two atoms should change.

2. the reactant side of a balanced chemical equation is shown below.

c3h8 + 5o2 →

how many oxygen atoms should there be on the product side in the equation?

2
5
7
10

1. The oxidation state of all the atoms should change

2. 10

Explanation:

Redox reactions are reactions in which one specie is reduced and another specie is oxidised simultaneously. Such reactions involves the transfer of electrons, that is, one specie loses electrons and the other accepts the lost electrons.

In a redox reaction, there is an increase in oxidation number of an atom that undergoes oxidation and a decrease in oxidation number for atoms that undergoes reduction.

2. There would 10 oxygen on the product side of the reaction.

In balancing chemical equations, the law of conservation of matter is usually followed. The law states that "matter is neither created nor destroyed in the course of a chemical action". This implies that the total mass of the reacting substance is exactly equal to the total mass of the products. This laws simply shows that every atom on the product end must be accounted for on the reactant side.

The equation which shows the combustion of propane would yield carbondioxide and water with the total number of oxygen atoms on the product end being 10.

The answer would be 10

Explanation:

these nuts

the answer for sodium is 0.186

the answer for rubidium is 0.251