If the system gains 25 kj of energy from the surroundings without doing any work on the surroundings, the surroundings could lose 20 kj of energy.

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).

it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.