Which of the following describes an exothermic reaction?

a + b imported asset ab + heat

a + bδ imported asset ab

heat + bc imported asset b + c

b + heat + cd imported asset bd + c

The answer to your question is:  letter A

Explanation:

a) A + B ⇒ AB + heat     It is an exothermic reaction because heat is released.

b) A + BΔ ⇒ AB  It heat added to the reactants , then it is an endothermic reaction.

c) heat + BC ⇒ B + C  It's an endothermic reaction because heat is added to the reactants.

d) B + heat + CD ⇒ BD + C  It's and endothermic reaction because heat is added to the reactants.

sorry idk the answer well to you i have a explaination

explanation: a formula which shows the arrangement of atoms in the molecule of a compound

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation: