07.01 Endothermic and Exothermic

Page 1: Introduction
How are energy transfers during chemical reactions explained and represented by potential diagrams?

Page 2: What is the relationship between heat, temperature, and thermal energy within a system?
Define the following terms: 
Thermochemistry: 
System: 

Complete the chart on the relationships of terms: 
Temperature	Thermal Energy	Heat	

Heat flows spontaneously from matter at a _________ temperature to matter at a _________ temperature.

The SI unit for energy that is most often used by scientists around the world is the ___________ (J) or _______________ (kJ). 

The amount of energy it takes to increase the temperature of one gram of water by one degree Celsius is called a _____________. 

Page 3: How does enthalpy change in endothermic and exothermic reactions?
Define the following terms: 
Enthalpy: 
Endothermic: 
Exothermic:

Complete the following statements.
The change of enthalpy (△H) in a system is equal to 

When heat is gained in a system, 

When heat is lost from a system, 

Complete the chart on systems: 
	Explanation	Example	
Isolated System			
Closed System			
Open System			

Page 4: How do potential energy diagrams represent energy transfers in chemical reactions?

Video: Enthalpy and Reactions Video
The positive or negative sign of enthalpy also relates to the slope of the line on a potential energy diagram.
	Type of Reaction	Explanation	

Page 5: How does activation energy affect the outcome of chemical reactions?
______________ is the energy needed to get a reaction started. 

Video: Activation Energy Video

Page 6: Which factors affect the solubility of a solute?

Practice 1: 
Complete the chart after mastering the practice: 
Endothermic	Exothermic	

Practice 2: 
1.	Which of the following represents an exothermic reaction?
2.	In the image below, which arrow represents activation energy? Which arrow represents the net change in energy of this reaction, or the total amount of energy absorbed by the reaction?

07.02 Enthalpy Values

Page 1: Introduction
How do scientists calculate enthalpy for physical and chemical changes, and how does that help distinguish between endothermic and exothermic changes?

Page 2: What is the relationship between heat, temperature, and thermal energy within a system?
___________________ is the energy needed to change temperature. 

Video: Specific Heat Capacity Video

Practice: 
1.	Starting at 25 °C, the items below each absorb 1 kJ of thermal energy. Which do you think will have the largest increase in temperature based on their given specific heats?
2.	Which swimming pool will warm up faster?

Page 3: How are energy transfers calculated using a temperature change?

Video: Calculating Enthalpy Video

 q = m × c × △T

q = 
m = 
c = 
△T =

Page 4: Practice

1.	A frying pan with 5 grams of vegetable oil is heated on a stove top. If the temperature of the oil increases from 25.0 °C to 95.0 °C, how much energy does the oil absorb?
2.	7.5 grams of sodium is heated on a hot plate. If the temperature of the sodium increases from 22.0 °C to 35.0 °C, how much heat does the sodium absorb?
3.	Calculate the number of joules released when 72.5 grams of water at 95.0 °C cools to a final temperature of 28.0 °C.

Phase Change	Enthalpy Type	

Page 5: How is the heat of reaction calculated for a chemical reaction?

The sum of the enthalpies of the reactants compared to the sum of the enthalpies of the products is _________________.

Complete the charts based on bonds relating to energy. 
Endothermic	Exothermic	

△H = Hproducts − Hreactants

The enthalpy change of a reaction or process is usually expressed in kilojoules per mole (kJ/mol) in a ___________________.

Practice: 
1.	The combustion of isooctane fuel (C8H18) has an enthalpy change of −5,460 kJ/mol. How many kilojoules of energy are released when 350.0 grams of isooctane are burned?
2.	If you burned 20.0 grams of methane, how many kilojoules of energy would you expect to be given off?
CH4 + O2 → CO2 + 2H2O

△H = −890.0 kJ/mol

07.03 Honors Calorimetry

Page 1: Introduction
How do chemists measure heat transfers between a system and its surroundings, and how does this process help with enthalpy and specific heat calculations?

Page 2: How does entropy influence chemical processes?
___________________ affects the spontaneity of a reaction. 

Complete the chart based on the pyramid of rising entropy.
		Explanation and examples	
Solid	Level 1		
	Level 2		
Liquid	Level 3		
	Level 4		
Aqueous	Level 5		
	Level 6		
Gas	Level 7		

Practice: 
Determine if each of the following changes would result in an increase or decrease in entropy (disorder).
1.	Freezing water into ice
2.	Dissolving salt in water
3.	Evaporating rubbing alcohol
4.	The reaction of carbon dioxide gas with solid calcium oxide to produce solid calcium carbonate
CO2(g) + CaO(s) → CaCO3(s)
5.	The decomposition of solid potassium chlorate to produce solid potassium chloride and oxygen gas
2KClO3(s) → 2KCl(s) + 3O2(g)

Page 3: How does calorimetry measure energy transfers during chemical and physical processes?
Define the following terms. 
Calorimeter: 
Calorimetry: 

Video: Calorimetry and Calorimeters Video

Complete the statement: 
Changes in calorimeters follow the law of conservation of energy because

q = m × c × △T

q is positive = 
q is negative = 

Page 4: How are energy transfers calculated using calorimetric data?

qsurroundings = −qsystem

m × c × △T = −(m × c × △T)

Video: Calorimetry and Calorimeters Video

Page 5: Practice
1.	A 30.0 g sample of water at 10.0 °C is mixed with 50.0 g of water at 57.0 °C inside a calorimeter. Calculate the final temperature of the mixture.
2.	A 5-gram sample of magnesium was burned in a calorimeter. The heat released by the combustion changed the temperature of 500.0 grams of water from 25.0 degrees Celsius to 41.0 degrees Celsius. How much energy, in joules, was released by the burning of the magnesium?

Page 6: How is calorimetry used to calculate specific heat capacity?

Video: Calorimetry and Calorimeters Video

Practice: 
1.	A 150.0-gram sample of metal at 75.0 °C is added to 150.0 g of water at 15.0 °C. The temperature of the water rises to 18.3 °C. What is the specific heat of the metal?
2.	A 65.0-gram piece of metal at 85.5 °C is placed in 100.0 g of water in a coffee cup calorimeter at 23.5 °C. Everything comes to the same temperature at 28.4 °C. What is the specific heat of the metal?

Page 7: Practice

1.	Using the formula qmetal = m × c × ΔT, calculate the specific heat of the known metal. Use the data from your activity for the metal in your calculation.

The specific heat capacity of water is 4.186 J/g°C

2.	Using the formula qunknown metal = m × c × ΔT, calculate the specific heat of the unknown metal A. Use the data from your experiment for the unknown metal in your calculation.

07.04 Reaction Rates

Page 1: Introduction
What influences the rate of chemical reactions, and how is reaction rate determined?

Page 2: How do particle collisions determine the success of a chemical reaction?

___________________ is the basis of the theory that for particles to react successfully, they must collide.

Complete the chart based on factors that influence the rate of reaction
Speed of Reaction	Particle Alignment	Adding Thermal Energy	

The more complex reactants are, the _______________ it is for them to align with one another.

Based on Maxwell-Boltzmann distribution curves:

1.	 
2.	  

Page 3: What factors affect the rate of a chemical reaction?

Video: Factors That Affect Rate Video

Complete the chart on factors that influence rates. 
Concentration and Rate	Temperature and Rate	Catalysts and Rate	

Page 4: How can you calculate the average rate of reaction?
Write the average rate formula

The value of the rate of reaction will often come out negative when using the concentration of a reactant to calculate it because the concentration of the reactant _____________ over time. 

Rates are usually reported as _____________ values because the negative indicates that the reactant is being consumed, not that the reaction has a negative rate. Let's look at some examples below.

Practice: 
Using the data, answer the following questions. For the decomposition of hydrogen peroxide, the concentration of hydrogen peroxide is measured at different points throughout the reaction.
H2O2 → 2H2O + O2
Time	0 s	2.6 × 104 s	4.32 × 104 s	6.48 × 104 s	8.64 × 104 s	
Concentration of H2O2	1.000 M	0.500 M	0.250 M	0.125 M	0.0625 M	

1.	What is the average rate of this reaction over the first 4.32 × 104 seconds?
2.	What is the average rate over the entire time of the experiment?
3.	What observation is made comparing the short interval over the entire interval?

07.05 Equilibrium

Page 1: Introduction
How do the reaction rate and concentration of the reactants and products in a chemical reaction affect equilibrium?          

Chemical stability is also known as__________________. 

Page 2: How do you recognize dynamic equilibrium in chemical reactions?
Take video notes: Equilibrium Reactions Video

In dynamic equilibrium, the rates of the forward and reverse reactions are __________ even though the forward and reverse reactions continue to occur.

In a closed system, reactions reach dynamic equilibrium when:
1.	  
2.	   

A + B ⇄ C + D

Describe the reactions. 

Forward reactions: 

Reverse or backward reactions: 

Page 3: How do forward and reverse reactions reach dynamic equilibrium?
Take video notes: Equilibrium Misconceptions Video

Page 4: How can physical changes lead to dynamic equilibrium?
Dynamic equilibrium is also possible during ________________ and ______________, which are both physical changes.

Take video notes: Chemical Equilibrium Video
07.06 Honors Le Châtelier's Principle

Page 1: Introduction
How can scientists change the position of equilibrium by applying Le Châtelier's principle?

Page 2: How does Le Châtelier's principle predict changes to dynamic equilibrium?
Take video notes: Le Châtelier's Principle Video

Equilibrium reactions show the forward and reverse reactions occurring simultaneously using a double arrow pointed in both directions in the chemical equation.

A + B ⇄ C + D

The language we use to describe the effect a stress has on an equilibrium reaction is as follows:
1.	 
2.	  

The addition of a catalyst ____________ the rate of a reaction by providing an alternative reaction pathway that requires less activation energy.

Since a catalyst lowers the activation energy for both the forward and the reverse reactions, it will have ______________ on the equilibrium position of a system.

Page 3: How can changes in concentration shift the position of equilibrium?
Video: Concentration and Equilibrium Video
Compete the chart on Le Châtelier's Principle for Concentration:
Component is added	Component is removed	

Page 4: How can changes in pressure shift the position of equilibrium?
Video: Pressure and Equilibrium Video

Compete the chart on Le Châtelier's Principle for Pressure:
Pressure is increased	Pressure is decreased	

Page 4: How can temperature changes shift the position of equilibrium?
Video: Changes in Temperature Video

Compete the chart on Le Châtelier's Principle for Temperature:
Temperature is increased	Temperature is decreased	

		

Page 4: Practice
Practice 1: 
1.	 
2.	 
3.	 
4.	 
5.	 
6.	 

Practice 2: 

A + B ⇄ C + D

1.	Adding more of A or B will cause the system to [shift left, shift right, stay the same] to reach a new equilibrium.
2.	Removing some of A or B from the system will cause the equilibrium position to [shift left, shift right, stay the same].

A + B ⇄ C + D + energy

3.	Increasing the temperature will cause the system to [shift left, shift right, stay the same] to reach a new equilibrium.
4.	Decreasing the temperature will cause the system to [shift left, shift right, stay the same] to reach a new equilibrium.

2SO2(g) + O2(g) ⇄ 2SO3(g)
5.	A decrease in pressure will cause the system to [shift left, shift right, stay the same] because there are [more, fewer, the same number of] moles of gas on the left side than on the right side of the equation.

P4(s) + 6Cl2(g) ⇄ 4PCl3(l)

6.	A decrease in volume and increase in pressure will cause the system to [shift left, shift right, stay the same] because there are [more, fewer, the same number of] moles of gas on the left side than the right side of the equation.

H2(g) + F2(g) ⇄ 2HF(g

7.	An increase in volume and decrease in pressure will cause the system to [shift left, shift right, stay the same] because there are [more, fewer, the same number of] moles of gas on the left side than the right side of the equation.