Question

Question
1
Question
2
Question
3
A)
Which result occurs during an exothermic reaction?
(1 point)
Light or heat are released into the environment.
Light and heat are absorbed from the environment.
Light is released into the environment, while heat is absorbed.
Heat is released into the environment, while light is absorbed.
A)
Which event is an example of an endothermic reaction?
(1 point)
photosynthesis
condensation
burning wood
rusting of iron
A)
How is total reaction energy calculated?
(1 point)
product bond energy ÷ reactant bond energy
product bond energy × reactant bond energy
reactant bond energy + product bond energy
reactant bond energy – product bond energy
Question
4
Question
5
A)
When producing hydrogen iodide, the energy of the reactants is 581 kJ/mol, and the energy of theproducts is 590 kJ/mol. The equation is shown.
H
+ I
→ 2HI
What is the total energy of the reaction? Is this an endothermic or exothermic reaction?
(1 point)
2
2
9 kJ/mol, exothermic
–9 kJ/mol, endothermic
9 kJ/mol, endothermic
–9 kJ/mol, exothermic
A)
The specific heat for iron is
. A piece of iron increases from
to
when
of energy is added to it. What is the mass of the iron?
(1 point)
0.450 J/g ⋅K 27.2°C 31.4°C
6204.87 J
0.0029 g
1.65 × 10−4 g
343 g
286 g

Answer 1

1) Light or heat are released into the environment.
(Exothermic reactions release energy.)

2) Photosynthesis.
(Photosynthesis absorbs energy from sunlight → endothermic.)

3) reactant bond energy − product bond energy.
(Reaction energy = energy to break bonds − energy released forming new bonds.)

4) +9 kJ/mol, endothermic.
(590 − 581 = +9 kJ/mol; positive ΔH = energy absorbed → endothermic.)

5) Using q = mcΔT: m = q / (c ΔT). With c = 0.450 J/g·K and ΔT = 31.4 − 27.2 = 4.2 K,
m = 6204.87 J / (0.450 J/g·K × 4.2 K) ≈ 3.28 × 10^3 g (≈ 3282 g).
None of the provided masses exactly match this value; the closest listed answer is 343 g, so choose 343 g if you must pick one from the options.