What change occurs during the reaction: mno4- > mn2+? five electrons are lost. three electrons are lost. five electrons are gained. three electrons are gained.

Five electrons are gained.

Explanation:

Oxidation number or oxidation state of an atom in a chemical compound is  the number of electrons lost or gained. It is also defined as the degree of oxidation of the atom in the compound.

This is a theoretical number which can help to decipher the oxidation and reduction in a redox reaction.

Oxidation is the loss of electrons. The specie which is oxidized has has elevation in its oxidation state as compared in the reactant and the products.

The given reaction is shown below as:

Manganese in has oxidation state of +7

Manganese in has an oxidation state of +2

It reduces from +7 to +2 . It means that 5 electrons are gained.

calculate how many grams of ammonia can be produced from 4.21 grams of

n2 + 3h2 = 2nh3

my answer:

25.0g n2 x (1 mol/ 28.0gn2) x (2 mol nh3/ 1 mol n2) x (17.0g nh3/ 1 molnh3) = 30.36g n2

25.0g h2 x (1 mol h2/ 2.00g h2) x (2 mol nh3/ 3 mol h2) x (17.0g nh3/ 1 mol nh3) = 141.67g h2

lr = n2

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.