Question

Question
1
A)
Which phrase describes the initial input of energy that is needed to break bonds in a chemicalreaction?
(1 point)
kinetic energy
potential energy
bond energy
activation energy
Question
2
A)
Use the diagram to answer the question.
The diagram represents the reaction of hydrogen gas and oxygen gas to produce water. Whichstatement best describes the reaction?
(1 point)
More energy is needed to break the bonds of the reactants than is released in the formation of the
products, so the reaction is endothermic.
More energy is needed to break the bonds of the reactants than is released in the formation of the
products, so the reaction is exothermic.
More energy is released in the formation of the products than is needed to break the bonds of the
reactants, so the reaction is exothermic.
More energy is released in the formation of the products than is needed to break the bonds of the
reactants, so the reaction is endothermic.
Question
3
Question
4
A)
Hydrogen gas (H
) and oxygen gas (O
) combine. Which change occurs that indicates a release ofbond energy?
(1 point)
2
2
a strong odor
a loud popping noise
the formation of CO2 bubbles
the appearance of color in the gases
A)
Which statement explains why the electrolysis of hydrochloric acid (HCl) is an endothermic reaction?
(1 point)
It releases more energy than it absorbs.
It requires bonds to be broken.
It requires electricity to sustain the reaction.
It results in two distinct gases, not liquids or solids.
Question
5
A)
Use the chemical equation to answer the question.
2H
(
g
) + O
(
g
) → 2H
O(
l
)
Which statement describes the breaking and forming of bonds in the reaction?
(1 point)
2
2
2
The reaction requires breaking four O–H bonds, and then forming one H–H bond and two O–O bonds.
The reaction requires breaking one O–O bond and two H–H bonds, and then forming four O–H bonds.
The reaction requires breaking four O–H bonds, and then forming one O–O bond and two H–H bonds.
The reaction requires breaking one H–H bond and two O=O bonds, and then forming four O–H bonds.

Answer 1

Here are the answers:

1) Activation energy.

2) More energy is released in the formation of the products than is needed to break the bonds of the reactants, so the reaction is exothermic.

3) (No question provided.)

4a) A loud popping noise. (The noise indicates release of energy from bond formation.)

4b) It requires electricity to sustain the reaction. (Electrolysis needs an input of electrical energy, so it is endothermic.)

5) The reaction requires breaking one O–O bond and two H–H bonds, and then forming four O–H bonds.