Question

question 6 (1 point)
what observation supports the idea that burning ethanol is a chemical reaction?
a the ethanol turned into water without any other changes
b the ethanol produced heat and light during burning
c the ethanol became solid after burning
d the ethanol released only cold gas

question 7 (1 point)
if the particles represented on the graph are speeding up, what can we infer about the energy change?
a no energy is involved in bond breaking.
b energy is being absorbed into the system.
c energy is constant.
d energy is being released to the surroundings.

Explanation:

For Question 6: A chemical reaction involves new substance formation and energy changes. Burning ethanol (combustion) is an exothermic reaction that releases heat and light, which is a key sign of a chemical change. Option a is incorrect because ethanol forms water AND carbon dioxide; option c is incorrect as ethanol burns to form gaseous products, not solid; option d is incorrect as burning releases hot gases and energy.
For Question 7: When particles speed up, their kinetic energy increases, which means the system is absorbing energy to make particles move faster. Option a is incorrect because bond breaking requires energy; option c is incorrect because energy changes occur when particle speed changes; option d is incorrect as releasing energy would slow particles down.

Answer:

Question 6: b. The ethanol produced heat and light during burning
Question 7: b. Energy is being absorbed into the system.