Question
Question 1
A)Which event is an example of an exothermic reaction?(1 point)
Responses
decomposition
decomposition
melting ice
melting ice
combustion
combustion
evaporation
evaporation
Question 2
A)
Use the reaction equation and bond energies to answer the question.
2H2O ---> 2H2 + O2
H-O: 467 kJ / mol
H-H: 432 kJ / mol
O=O: 498 kJ / mol
What is the total energy of the reaction? Is this an endothermic or exothermic reaction?
(1 point)
Responses
-506 kJ / mol, exothermic
-506 kJ / mol, exothermic
506 kJ / mol, exothermic
506 kJ / mol, exothermic
-506 kJ / mol, endothermic
-506 kJ / mol, endothermic
506 kJ / mol, endothermic
506 kJ / mol, endothermic
Question 3
A)
Use the image to answer the question.
Which kind of reaction is shown in this image?
(1 point)
Responses
It is an endothermic reaction because the surroundings take energy from the system.
It is an endothermic reaction because the surroundings take energy from the system.
It is an exothermic reaction because the surroundings take energy from the system.
It is an exothermic reaction because the surroundings take energy from the system.
It is an endothermic reaction because the system takes energy from the surroundings.
It is an endothermic reaction because the system takes energy from the surroundings.
It is an exothermic reaction because the system takes energy from the surroundings.
It is an exothermic reaction because the system takes energy from the surroundings.
Question 4
A)A student pours ammonium nitrate into a container of room temperature water. The student stirs the mixture with a stirring rod and then feels the outside of the container, which is cold to the touch. Which material is part of the system that absorbed the heat?(1 point)
Responses
the water
the water
the stirring rod
the stirring rod
the container
the container
the air
the air
Question 5
A)
Use the chemical equation and the bond diagram to answer the question.
2H2 + O2 ---> 2H2O
2H-H + O=O ---> 2H-O-H
The energy of the H-H bonds is 342 kJ / mol. The energy of the O=O bond is 498 kJ / mol. The energy of the O-H bond is 467 kJ / mol.
Which bond is the weakest?
(1 point)
Responses
O=O
O=O
O-H
O-H
H-H
H-H
O-O
O-O
Question 6
A)
Use the reaction and bond information to answer the question.
H2 + CO2 ---> CH2O2
Reactant bond energies: H-H is 432 kJ / mol, C=O is 799 kJ / mol
Product bond energies: C-H is 413 kJ / mol, C=O is 745 kJ / mol, C-O is 358 kJ / mol, O-H is 467 kJ / mol
Is the system endothermic or exothermic and why?
(1 point)
Responses
It is endothermic because more energy is given off by the products versus the amount needed to break up the reactants.
It is endothermic because more energy is given off by the products versus the amount needed to break up the reactants.
It is exothermic because more energy is given off by the products versus the amount needed to break up the reactants.
It is exothermic because more energy is given off by the products versus the amount needed to break up the reactants.
It is endothermic because more energy is needed to break up the reactants versus the amount given off by the products.
It is endothermic because more energy is needed to break up the reactants versus the amount given off by the products.
It is exothermic because more energy is needed to break up the reactants versus the amount given off by the products.
It is exothermic because more energy is needed to break up the reactants versus the amount given off by the products.
Question 7
A)
Use the table to answer the question.
Compound Electronegativity Difference
CO 0.89
NaCl 2.23
NO 0.04
CaBr 1.96
Which compound is most likely to be held together by a covalent bond based on the electronegativity difference between its two atoms?
(1 point)
Responses
CO
CO
NaCl
NaCl
CaBr
CaBr
NO
NO
Question 8
A)
Use the table of information about bond energies to answer the question.
Bond Energy (kJ / mol)
C-Cl 339
C-F 485
H-Cl 427
H-F 565
Which bond is more stable?
(1 point)
Responses
H-F
H-F
C-Cl
C-Cl
H-Cl
H-Cl
C-F
C-F
Question 9
A)Which option is an example of energy transfer via radiation?(1 point)
Responses
a hot air balloon rising
a hot air balloon rising
using a heating pad to warm stiff muscles
using a heating pad to warm stiff muscles
melting ice in your hand
melting ice in your hand
sunlight warming a concrete sidewalk
sunlight warming a concrete sidewalk
Question 10
A)A closed system includes a cup of warm water an an ice cube that was just placed inside of it. Which statement describes the energy of the system over time?(1 point)
Responses
The total energy of the system will decrease as the warm water causes the ice molecules to lose kinetic energy.
The total energy of the system will decrease as the warm water causes the ice molecules to lose kinetic energy.
The total energy of the system will decrease as the ice causes the warm water molecules to lose kinetic energy.
The total energy of the system will decrease as the ice causes the warm water molecules to lose kinetic energy.
The total energy of the system will stay the same as kinetic energy from the warm water decreases the kinetic energy of molecules in the ice.
The total energy of the system will stay the same as kinetic energy from the warm water decreases the kinetic energy of molecules in the ice.
The total energy of the system will stay the same as kinetic energy from the warm water increases the kinetic energy of molecules in the ice.
The total energy of the system will stay the same as kinetic energy from the warm water increases the kinetic energy of molecules in the ice.
Question 11
A)Which energy transformation occurs in an exothermic reaction?(1 point)
Responses
There is a net flow of energy from the surroundings into the the system.
There is a net flow of energy from the surroundings into the the system.
There is a net flow of energy from the system out to the surroundings.
There is a net flow of energy from the system out to the surroundings.
Energy from the surrounding is stored in the chemical bonds of the products.
Energy from the surrounding is stored in the chemical bonds of the products.
Energy from the chemical bonds of the reactants is released to the surroundings.
Energy from the chemical bonds of the reactants is released to the surroundings.
Question 12
A)What is activation energy?(1 point)
Responses
the kinetic energy of the reactants of a system after the reaction has begun
the kinetic energy of the reactants of a system after the reaction has begun
the energy released when atomic bonds are broken
the energy released when atomic bonds are broken
the total potential energy of the bonds of the reactants in a system
the total potential energy of the bonds of the reactants in a system
the energy that must be added to a system to break the bonds of the reactants
the energy that must be added to a system to break the bonds of the reactants
Question 13
A)Vinegar (acetic acid) and baking soda (sodium bicarbonate) react in an endothermic reaction to produce sodium acetate, carbon dioxide, and water.
Which statement justifies classifying the reaction as endothermic?(1 point)
Responses
The reaction produces water.
The reaction produces water.
The reaction needs a catalyst.
The reaction needs a catalyst.
The bonds in both the reactants and products are covalent bonds.
The bonds in both the reactants and products are covalent bonds.
The total potential energy of the reactants is less than the total potential energy of the products.
The total potential energy of the reactants is less than the total potential energy of the products.
Question 14
A)Consider cooking an egg in a pan over heat as an endothermic or exothermic process, and answer with the appropriate validation:(2 points)
Responses
Cooking an egg is an endothermic process because energy is released into the environment.
Cooking an egg is an endothermic process because energy is released into the environment.
Cooking an egg is an endothermic process because energy is absorbed by the egg from the environment.
Cooking an egg is an endothermic process because energy is absorbed by the egg from the environment.
Cooking an egg is an exothermic process because energy is released into the environment.
Cooking an egg is an exothermic process because energy is released into the environment.
Cooking an egg is an exothermic process because energy is absorbed by the egg from the environment.
Cooking an egg is an exothermic process because energy is absorbed by the egg from the environment.
Question 15
A)Consider the formation of snow as an endothermic or exothermic process, and answer with the correct response:(2 points)
Responses
When water freezes, it loses heat energy to its surroundings causing snow to form as an exothermic reaction.
When water freezes, it loses heat energy to its surroundings causing snow to form as an exothermic reaction.
When water freezes, it loses heat to its surroundings causing snow to form as an endothermic reaction.
When water freezes, it loses heat to its surroundings causing snow to form as an endothermic reaction.
When water freezes, it absorbs heat from its surroundings causing snow to form as an exothermic reaction.
When water freezes, it absorbs heat from its surroundings causing snow to form as an exothermic reaction.
When water freezes, it absorbs heat from its surroundings causing snow to form as an endothermic reaction.
When water freezes, it absorbs heat from its surroundings causing snow to form as an endothermic reaction.
Question 16
A)
Use the table to answer the question.
Bond Bond Energy
H-H 432
Cl-Cl 239
H-Cl 427
Consider the reaction H2 + Cl2 ---> 2HCl
Is this reaction endothermic or exothermic based on the information in the table? Choose the answer below that supports your claim.
(2 points)
Responses
The reaction is exothermic because the total bond energy of the equation is 183 kJ.
The reaction is exothermic because the total bond energy of the equation is 183 kJ.
The reaction is exothermic because the total bond energy of the equation is -183 kJ.
The reaction is exothermic because the total bond energy of the equation is -183 kJ.
The reaction is endothermic because the total bond energy of the equation is 183 kJ.
The reaction is endothermic because the total bond energy of the equation is 183 kJ.
The reaction is endothermic because the total bond energy of the equation is -183 kJ.
The reaction is endothermic because the total bond energy of the equation is -183 kJ.
A)Which event is an example of an exothermic reaction?(1 point)
Responses
decomposition
decomposition
melting ice
melting ice
combustion
combustion
evaporation
evaporation
Question 2
A)
Use the reaction equation and bond energies to answer the question.
2H2O ---> 2H2 + O2
H-O: 467 kJ / mol
H-H: 432 kJ / mol
O=O: 498 kJ / mol
What is the total energy of the reaction? Is this an endothermic or exothermic reaction?
(1 point)
Responses
-506 kJ / mol, exothermic
-506 kJ / mol, exothermic
506 kJ / mol, exothermic
506 kJ / mol, exothermic
-506 kJ / mol, endothermic
-506 kJ / mol, endothermic
506 kJ / mol, endothermic
506 kJ / mol, endothermic
Question 3
A)
Use the image to answer the question.
Which kind of reaction is shown in this image?
(1 point)
Responses
It is an endothermic reaction because the surroundings take energy from the system.
It is an endothermic reaction because the surroundings take energy from the system.
It is an exothermic reaction because the surroundings take energy from the system.
It is an exothermic reaction because the surroundings take energy from the system.
It is an endothermic reaction because the system takes energy from the surroundings.
It is an endothermic reaction because the system takes energy from the surroundings.
It is an exothermic reaction because the system takes energy from the surroundings.
It is an exothermic reaction because the system takes energy from the surroundings.
Question 4
A)A student pours ammonium nitrate into a container of room temperature water. The student stirs the mixture with a stirring rod and then feels the outside of the container, which is cold to the touch. Which material is part of the system that absorbed the heat?(1 point)
Responses
the water
the water
the stirring rod
the stirring rod
the container
the container
the air
the air
Question 5
A)
Use the chemical equation and the bond diagram to answer the question.
2H2 + O2 ---> 2H2O
2H-H + O=O ---> 2H-O-H
The energy of the H-H bonds is 342 kJ / mol. The energy of the O=O bond is 498 kJ / mol. The energy of the O-H bond is 467 kJ / mol.
Which bond is the weakest?
(1 point)
Responses
O=O
O=O
O-H
O-H
H-H
H-H
O-O
O-O
Question 6
A)
Use the reaction and bond information to answer the question.
H2 + CO2 ---> CH2O2
Reactant bond energies: H-H is 432 kJ / mol, C=O is 799 kJ / mol
Product bond energies: C-H is 413 kJ / mol, C=O is 745 kJ / mol, C-O is 358 kJ / mol, O-H is 467 kJ / mol
Is the system endothermic or exothermic and why?
(1 point)
Responses
It is endothermic because more energy is given off by the products versus the amount needed to break up the reactants.
It is endothermic because more energy is given off by the products versus the amount needed to break up the reactants.
It is exothermic because more energy is given off by the products versus the amount needed to break up the reactants.
It is exothermic because more energy is given off by the products versus the amount needed to break up the reactants.
It is endothermic because more energy is needed to break up the reactants versus the amount given off by the products.
It is endothermic because more energy is needed to break up the reactants versus the amount given off by the products.
It is exothermic because more energy is needed to break up the reactants versus the amount given off by the products.
It is exothermic because more energy is needed to break up the reactants versus the amount given off by the products.
Question 7
A)
Use the table to answer the question.
Compound Electronegativity Difference
CO 0.89
NaCl 2.23
NO 0.04
CaBr 1.96
Which compound is most likely to be held together by a covalent bond based on the electronegativity difference between its two atoms?
(1 point)
Responses
CO
CO
NaCl
NaCl
CaBr
CaBr
NO
NO
Question 8
A)
Use the table of information about bond energies to answer the question.
Bond Energy (kJ / mol)
C-Cl 339
C-F 485
H-Cl 427
H-F 565
Which bond is more stable?
(1 point)
Responses
H-F
H-F
C-Cl
C-Cl
H-Cl
H-Cl
C-F
C-F
Question 9
A)Which option is an example of energy transfer via radiation?(1 point)
Responses
a hot air balloon rising
a hot air balloon rising
using a heating pad to warm stiff muscles
using a heating pad to warm stiff muscles
melting ice in your hand
melting ice in your hand
sunlight warming a concrete sidewalk
sunlight warming a concrete sidewalk
Question 10
A)A closed system includes a cup of warm water an an ice cube that was just placed inside of it. Which statement describes the energy of the system over time?(1 point)
Responses
The total energy of the system will decrease as the warm water causes the ice molecules to lose kinetic energy.
The total energy of the system will decrease as the warm water causes the ice molecules to lose kinetic energy.
The total energy of the system will decrease as the ice causes the warm water molecules to lose kinetic energy.
The total energy of the system will decrease as the ice causes the warm water molecules to lose kinetic energy.
The total energy of the system will stay the same as kinetic energy from the warm water decreases the kinetic energy of molecules in the ice.
The total energy of the system will stay the same as kinetic energy from the warm water decreases the kinetic energy of molecules in the ice.
The total energy of the system will stay the same as kinetic energy from the warm water increases the kinetic energy of molecules in the ice.
The total energy of the system will stay the same as kinetic energy from the warm water increases the kinetic energy of molecules in the ice.
Question 11
A)Which energy transformation occurs in an exothermic reaction?(1 point)
Responses
There is a net flow of energy from the surroundings into the the system.
There is a net flow of energy from the surroundings into the the system.
There is a net flow of energy from the system out to the surroundings.
There is a net flow of energy from the system out to the surroundings.
Energy from the surrounding is stored in the chemical bonds of the products.
Energy from the surrounding is stored in the chemical bonds of the products.
Energy from the chemical bonds of the reactants is released to the surroundings.
Energy from the chemical bonds of the reactants is released to the surroundings.
Question 12
A)What is activation energy?(1 point)
Responses
the kinetic energy of the reactants of a system after the reaction has begun
the kinetic energy of the reactants of a system after the reaction has begun
the energy released when atomic bonds are broken
the energy released when atomic bonds are broken
the total potential energy of the bonds of the reactants in a system
the total potential energy of the bonds of the reactants in a system
the energy that must be added to a system to break the bonds of the reactants
the energy that must be added to a system to break the bonds of the reactants
Question 13
A)Vinegar (acetic acid) and baking soda (sodium bicarbonate) react in an endothermic reaction to produce sodium acetate, carbon dioxide, and water.
Which statement justifies classifying the reaction as endothermic?(1 point)
Responses
The reaction produces water.
The reaction produces water.
The reaction needs a catalyst.
The reaction needs a catalyst.
The bonds in both the reactants and products are covalent bonds.
The bonds in both the reactants and products are covalent bonds.
The total potential energy of the reactants is less than the total potential energy of the products.
The total potential energy of the reactants is less than the total potential energy of the products.
Question 14
A)Consider cooking an egg in a pan over heat as an endothermic or exothermic process, and answer with the appropriate validation:(2 points)
Responses
Cooking an egg is an endothermic process because energy is released into the environment.
Cooking an egg is an endothermic process because energy is released into the environment.
Cooking an egg is an endothermic process because energy is absorbed by the egg from the environment.
Cooking an egg is an endothermic process because energy is absorbed by the egg from the environment.
Cooking an egg is an exothermic process because energy is released into the environment.
Cooking an egg is an exothermic process because energy is released into the environment.
Cooking an egg is an exothermic process because energy is absorbed by the egg from the environment.
Cooking an egg is an exothermic process because energy is absorbed by the egg from the environment.
Question 15
A)Consider the formation of snow as an endothermic or exothermic process, and answer with the correct response:(2 points)
Responses
When water freezes, it loses heat energy to its surroundings causing snow to form as an exothermic reaction.
When water freezes, it loses heat energy to its surroundings causing snow to form as an exothermic reaction.
When water freezes, it loses heat to its surroundings causing snow to form as an endothermic reaction.
When water freezes, it loses heat to its surroundings causing snow to form as an endothermic reaction.
When water freezes, it absorbs heat from its surroundings causing snow to form as an exothermic reaction.
When water freezes, it absorbs heat from its surroundings causing snow to form as an exothermic reaction.
When water freezes, it absorbs heat from its surroundings causing snow to form as an endothermic reaction.
When water freezes, it absorbs heat from its surroundings causing snow to form as an endothermic reaction.
Question 16
A)
Use the table to answer the question.
Bond Bond Energy
H-H 432
Cl-Cl 239
H-Cl 427
Consider the reaction H2 + Cl2 ---> 2HCl
Is this reaction endothermic or exothermic based on the information in the table? Choose the answer below that supports your claim.
(2 points)
Responses
The reaction is exothermic because the total bond energy of the equation is 183 kJ.
The reaction is exothermic because the total bond energy of the equation is 183 kJ.
The reaction is exothermic because the total bond energy of the equation is -183 kJ.
The reaction is exothermic because the total bond energy of the equation is -183 kJ.
The reaction is endothermic because the total bond energy of the equation is 183 kJ.
The reaction is endothermic because the total bond energy of the equation is 183 kJ.
The reaction is endothermic because the total bond energy of the equation is -183 kJ.
The reaction is endothermic because the total bond energy of the equation is -183 kJ.
Answers
Answered by
GPT-4o mini
Here are the responses for the questions provided:
**Question 1**
**C)** combustion
**Answer:** combustion
---
**Question 2**
To calculate the total energy of the reaction, you need to consider the bond energies of the bonds being broken (reactants) and formed (products).
1. Total energy to break bonds:
- 2 H-O bonds in 2 H2O = 2 * 467 = 934 kJ
2. Total energy to form bonds:
- 2 H-H + 1 O=O = 2 * 432 + 498 = 1362 kJ
3. Total energy = Energy in (reactants) - Energy out (products)
934 kJ - 1362 kJ = -428 kJ
-506 kJ / mol is not the correct answer; please recalculate based on given data.
**Answer:** -428 kJ / mol (not listed, but should be exothermic).
---
**Question 3**
**C)** It is an endothermic reaction because the system takes energy from the surroundings.
**Answer:** It is an endothermic reaction because the system takes energy from the surroundings.
---
**Question 4**
**A)** the water
**Answer:** the water
---
**Question 5**
**C)** H-H
**Answer:** H-H
---
**Question 6**
To evaluate whether the reaction is exothermic or endothermic, you must calculate the bond energies involved.
1. Energy to break the bonds of the reactants:
- H-H = 432 kJ
- C=O (there are 2 from CO2) = 2 * 799 = 1598 kJ
Total energy for reactants = 432 + 1598 = 2030 kJ.
2. Energy to form the bonds of the products:
- C-H = 413 kJ
- C=O = 745 kJ
- C-O = 358 kJ
- O-H (there are 2 from the products) = 2 * 467 = 934 kJ
Total energy for products = 413 + 745 + 358 + 934 = 2450 kJ.
Now compare:
- Difference = 2030 kJ - 2450 kJ = -420 kJ.
Since more energy is needed to break reactants than is released during product formation, the reaction is endothermic.
**Answer:** It is endothermic because more energy is needed to break up the reactants versus the amount given off by the products.
---
**Question 7**
**B)** NO
**Answer:** NO
---
**Question 8**
**A)** H-F
**Answer:** H-F
---
**Question 9**
**D)** sunlight warming a concrete sidewalk
**Answer:** sunlight warming a concrete sidewalk
---
**Question 10**
**A)** The total energy of the system will decrease as the warm water causes the ice molecules to lose kinetic energy.
**Answer:** The total energy of the system will decrease as the warm water causes the ice molecules to lose kinetic energy.
---
**Question 11**
**B)** There is a net flow of energy from the system out to the surroundings.
**Answer:** There is a net flow of energy from the system out to the surroundings.
---
**Question 12**
**D)** the energy that must be added to a system to break the bonds of the reactants
**Answer:** the energy that must be added to a system to break the bonds of the reactants
---
**Question 13**
**D)** The total potential energy of the reactants is less than the total potential energy of the products.
**Answer:** The total potential energy of the reactants is less than the total potential energy of the products.
---
**Question 14**
**B)** Cooking an egg is an endothermic process because energy is absorbed by the egg from the environment.
**Answer:** Cooking an egg is an endothermic process because energy is absorbed by the egg from the environment.
---
**Question 15**
**A)** When water freezes, it loses heat energy to its surroundings causing snow to form as an exothermic reaction.
**Answer:** When water freezes, it loses heat energy to its surroundings causing snow to form as an exothermic reaction.
---
**Question 16**
- Calculate the bond energies:
**Reactants:**
- Bonds broken: H-H and Cl-Cl.
Total energy = 432 + 239 = 671 kJ.
**Products:**
- Bonds formed: 2 HCl.
Total energy = 2 * 427 = 854 kJ.
The difference is:
**Energy change = Energy needed to break bonds - Energy released when new bonds are formed**
671 kJ - 854 kJ = -183 kJ, indicating it is exothermic.
**Answer:** The reaction is exothermic because the total bond energy of the equation is -183 kJ.
---
Feel free to verify or recalculate any information as necessary!
**Question 1**
**C)** combustion
**Answer:** combustion
---
**Question 2**
To calculate the total energy of the reaction, you need to consider the bond energies of the bonds being broken (reactants) and formed (products).
1. Total energy to break bonds:
- 2 H-O bonds in 2 H2O = 2 * 467 = 934 kJ
2. Total energy to form bonds:
- 2 H-H + 1 O=O = 2 * 432 + 498 = 1362 kJ
3. Total energy = Energy in (reactants) - Energy out (products)
934 kJ - 1362 kJ = -428 kJ
-506 kJ / mol is not the correct answer; please recalculate based on given data.
**Answer:** -428 kJ / mol (not listed, but should be exothermic).
---
**Question 3**
**C)** It is an endothermic reaction because the system takes energy from the surroundings.
**Answer:** It is an endothermic reaction because the system takes energy from the surroundings.
---
**Question 4**
**A)** the water
**Answer:** the water
---
**Question 5**
**C)** H-H
**Answer:** H-H
---
**Question 6**
To evaluate whether the reaction is exothermic or endothermic, you must calculate the bond energies involved.
1. Energy to break the bonds of the reactants:
- H-H = 432 kJ
- C=O (there are 2 from CO2) = 2 * 799 = 1598 kJ
Total energy for reactants = 432 + 1598 = 2030 kJ.
2. Energy to form the bonds of the products:
- C-H = 413 kJ
- C=O = 745 kJ
- C-O = 358 kJ
- O-H (there are 2 from the products) = 2 * 467 = 934 kJ
Total energy for products = 413 + 745 + 358 + 934 = 2450 kJ.
Now compare:
- Difference = 2030 kJ - 2450 kJ = -420 kJ.
Since more energy is needed to break reactants than is released during product formation, the reaction is endothermic.
**Answer:** It is endothermic because more energy is needed to break up the reactants versus the amount given off by the products.
---
**Question 7**
**B)** NO
**Answer:** NO
---
**Question 8**
**A)** H-F
**Answer:** H-F
---
**Question 9**
**D)** sunlight warming a concrete sidewalk
**Answer:** sunlight warming a concrete sidewalk
---
**Question 10**
**A)** The total energy of the system will decrease as the warm water causes the ice molecules to lose kinetic energy.
**Answer:** The total energy of the system will decrease as the warm water causes the ice molecules to lose kinetic energy.
---
**Question 11**
**B)** There is a net flow of energy from the system out to the surroundings.
**Answer:** There is a net flow of energy from the system out to the surroundings.
---
**Question 12**
**D)** the energy that must be added to a system to break the bonds of the reactants
**Answer:** the energy that must be added to a system to break the bonds of the reactants
---
**Question 13**
**D)** The total potential energy of the reactants is less than the total potential energy of the products.
**Answer:** The total potential energy of the reactants is less than the total potential energy of the products.
---
**Question 14**
**B)** Cooking an egg is an endothermic process because energy is absorbed by the egg from the environment.
**Answer:** Cooking an egg is an endothermic process because energy is absorbed by the egg from the environment.
---
**Question 15**
**A)** When water freezes, it loses heat energy to its surroundings causing snow to form as an exothermic reaction.
**Answer:** When water freezes, it loses heat energy to its surroundings causing snow to form as an exothermic reaction.
---
**Question 16**
- Calculate the bond energies:
**Reactants:**
- Bonds broken: H-H and Cl-Cl.
Total energy = 432 + 239 = 671 kJ.
**Products:**
- Bonds formed: 2 HCl.
Total energy = 2 * 427 = 854 kJ.
The difference is:
**Energy change = Energy needed to break bonds - Energy released when new bonds are formed**
671 kJ - 854 kJ = -183 kJ, indicating it is exothermic.
**Answer:** The reaction is exothermic because the total bond energy of the equation is -183 kJ.
---
Feel free to verify or recalculate any information as necessary!