Changes in the total amount of thermal energy provide evidence that chemical reactions have taken place. A chemical reaction in which energy has been absorbed is known as a(n): Select one:
physical reaction.

endothermic reaction.

reversible reaction.

exothermic reaction.

B. endothermic reaction

Explanation:

while cooking a piece of 1/2 pound beef steak, a cast iron pan (2.4kg in weight) was heated 260 celsius.

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.