Chemistry Chapter 7: Energy, Rate, and Equilibrium
Which of the following options represent ( s ) an exothermic reaction ?
AB + CD -> AD + BC + heat . The reaction of 1 mole of CH4 ( g ) with 1 mole of Cl₂ ( g ) releases 26.4 kcal of heat .
Exothermic reactions are ________ spontaneous and endothermic reactions are ________ spontaneous .
often ; sometimes
When a chlorine - chlorine bond is formed , 58 kcal of energy is ________. To break the same bond , 58 kcal of energy is _________.
released ; absorbed
An increase in entropy for a chemical reaction occurs when _______ .
the entropy of the products is greater than that of the reactants .
The specific heat of a substance is defined as ________ .
the number of calories of heat needed to raise the temperature of 1 gram of the substance 1 degree Celsius
Free energy change is symbolized by which of the following ?
(Delta)G
Match each thermodynamic parameter to the correct description in terms of the system .
(Delta)G < 0 <————> Spontaneous process (Delta)G > 0 <————> Nonspontaneous process (Delta)H < 0 <————> Exothermic process (Delta)H > 0 <————> Endothermic process (Delta)S > 0 <————> Process moves to a state of increased disorder
(Delta)G =
(Delta)H - T(Delta)S
Which sets of thermodynamic parameters represent a spontaneous process in terms of the system ? Select all that apply .
(Delta)H < 0 , (Delta)S > 0 (Delta)G < 0
Match each set of thermodynamic parameters to the correct description .
(Delta)H > 0 , (Delta)S > 0 <————> Sign of (Delta)G depends on temperature . (Delta)H > 0 , (Delta)S < 0 <————> (Delta)G > 0 at all temperatures (Delta)H < 0 , (Delta)S > 0 <————> (Delta)G < 0 at all temperatures
What factors favor a spontaneous chemical reaction ? Select all that apply .
- (Delta)Sreaction > 0 - The chemical reaction is exothermic . - An increase in entropy
Which of the following statements correctly describe energy changes in chemical reactions ? Select all that apply .
- Any energy that is lost from the system is gained by the surroundings . - Energy that is exchanged between the system and the surroundings in the form of heat can be measured through changes in temperature . - Changes in energy as a chemical reaction occurs can be measured .
Match each type of reaction to the correct definition . The reaction is defined as the system .
- Exothermic reaction <————> The reaction releases energy to the surroundings . - Endothermic reaction <————> The reaction absorbs energy from the surroundings .
Match each thermochemical equation to the correct description .
- Exothermic reaction <————> A + B -> C + D + heat - Endothermic reaction <————> heat + A + B -> C + D - 55 kcal + A + B -> C + D <————> Endothermic reaction - A + B -> C + D + 55 kcal <————> Exothermic reaction
Match each type of reaction to the correct description concerning the following process : A - B + C - D -> A - C + B - D
- Endothermic reaction <————> The energy required to break the bonds in the reactants is greater than the energy released from forming bonds in the products . - Exothermic reaction <————> The energy required to break the bonds in the reactants is less than the energy released from forming bonds in the products .
Which of the following options correctly describe calorimetry ? Select all that apply .
- Calorimetry involves the measurement of the change in temperature of a quantity of water or solution that is in contact with a reaction . - Calorimetry is the measurement of heat energy changes in a chemical reaction . - The device used to measure heat changes in a system is called a calorimeter .
Which of the following options correctly describe a change in free energy ? Select all that apply .
- Free energy change is the combined contribution of the enthalpy and entropy values for a chemical reaction . - Free energy change is the ultimate predictor of reaction spontaneity .
Which of the following substances is / are expected to have a higher entropy than H₂O ( l ) ? Select all that apply .
- H₂O ( g ) - CO₂ ( g )
Which of the following options correctly describe a bomb calorimeter ? Select all that apply .
- In a bomb calorimeter , the chemical reaction under study is placed in a sealed reaction chamber . - A bomb calorimeter is useful for measuring the fuel value of foods .
A combustion reaction results in an increase in temperature of the air surrounding the reaction . Which of the following statements correctly describe this process ? Select all that apply .
- Some of the energy stored in the bonds of the reactants is converted to kinetic energy . - Heat is transfered from the system to the surroundings . - Calorimetry may be used to determine the heat of the reaction through measuring changes in temperature .
Which of the following processes are associated with an increase of entropy ? Select all that apply .
- Sublimation - Vaporization - Expansion of a gas into an evacuated chamber - Melting
Match each term to the correct description when describing changes in energy .
- System <————> The process under study . - Surroundings <————> Everything in the universe other than the process under study . - Change in energy <————> Energy absorbed or released .
Which of the following statements correctly describe the kinetic molecular theory of gases ? Select all that apply .
- The average kinetic energy of gaseous atoms or molecules increases with increasing temperature . - Gaseous molecules and atoms undergo frequent collisions . - Gaseous molecules and atoms are in constant motion .
Which of the following options correctly describes enthalpy ?
- The change in enthalpy is represented by the symbol (Delta)H. - The change in enthalpy is the energy difference between the products and reactants of a chemical reaction . - Enthalpy is a term used to represent heat .
Thermodynamics includes the study of _________. Select all that apply .
- energy - work - heat
When the energy required to break bonds is ________ the energy released when forming bonds in a chemical reaction , the reaction is characterized as ________. Select all that apply .
- greater than , endothermic - less than ; exothermic
Thermodynamics may be applied to _________. Select all that apply .
- the calculation of the quantity of energy released or consumed in a physical change. - the study of heat lost or gained when a substance changes phase. - the calculation of the quantity of heat obtained from a chemical reaction. - the study of energy , work , and heat for a chemical process.
Rank the following states of matter for a given substance in order of increasing entropy . The state with the lowest entropy belongs at the top of the list
1. Solid 2. Liquid 3. Gas
In nutrition science , the nutritional Calorie is equal to ________ calorie ( s ) and has the symbol ________ .
1000 ; Cal
0.100 moles of an acid is mixed with 0.100 moles of a base in a calorimeter and the temperature of 85.0 g of the resulting solution increases from 23.3 ° C to 34.5 ° C . If the specific heat of the solution is 1.00 cal / g ° C , what is the quantity of energy released or absorbed by the reaction ?
952 cal released
Which of the following processes are endothermic ? Select all that apply .
A + B -> C + D , (Delta)H = 21.1 kcal SO₂ ( g ) -> S ( s ) + O₂ ( g ) , (Delta)H = 71 kcal
Classify ( match ) each process as an exothermic or endothermic change .
A Br - Br bond is broken . <————> Endothermic A Br - Br bond is formed . <————> Exothermic
Some molecular collisions , with sufficient energy , will _________ bonds in molecules and allow for new bonds to _________.
Blank 1 : break Blank 2 : form
Bond ________ always requires an input of energy , whereas bond ________ involves a release of energy .
Blank 1 : breaking , cleavage , dissociation , breakage , or cleaving Blank 2 : formation , making , or forming
A bomb calorimeter measures the heat released when a sample is _______ .
Blank 1 : combusted , burned , or burnt
The spontaneity of a chemical reaction depends on the relative magnitude of the ________ and ________ values .
Blank 1 : enthalpy Blank 2 : entropy
Apart from enthalpy changes , another factor that affects reaction spontaneity is ________ , which is related to the freedom of movement within a system .
Blank 1 : entropy
The measure of the randomness or disorder of a chemical system is called
Blank 1 : entropy
The amount of energy per gram of a given food is called its ________ value .
Blank 1 : fuel
Fuel value is given as the number of nutritional Calories per ________ of food .
Blank 1 : gram
The change in enthalpy is the energy difference between the ________ and ________ of a chemical reaction and is symbolized as (Delta)H .
Blank 1 : products Blank 2 : reactants
Which of the following reactions are exothermic ? Select all that apply ..
C6H12O6 ( s ) -> 2C₂H6O ( P ) + 2CO₂ ( g ) + 16 kcal CH4 ( g ) + 2O₂ ( g ) -> CO₂ ( g ) + 2H₂O ( P ) + 213 kcal
Match each process to the correct change in entropy associated with it .
Condensation <————> Decrease in entropy Vaporization <————> Increase in entropy Increase in entropy <————> Decomposition of a liquid to form gaseous molecules Decrease in entropy <————> Separation of a gaseous mixture into individual components
Match each type of reaction to the correct description .
Endothermic reaction <————> Surroundings become colder as the reaction absorbs heat from the surroundings Exothermic reaction <————> Surroundings become warmer as the reaction releases heat to the surroundings Energy is a reactant and is required in the reaction . <————> Endothermic reaction Energy is a product and is released in the reaction . <————> Exothermic reaction
Match each reaction enthalpy , (Delta)H , with the term that generally describes it .
Exothermic <————> AH < 0 Endothermic <————> AH > 0
True or False : 1 Calorie = 1 calorie
False
Match each sentence beginning to the correct sentence ending to describe what occurs in calorimetry .
For an exothermic reaction <————> heat released by the reaction is absorbed by the surrounding solution . For an endothermic reaction <————> the reactants absorb heat from the solution . The temperature of the solution increases <————> in the case of an exothermic reaction . The temperature of the solution decreases <————> in the case of an endothermic reaction .
Which of the following reactions are endothermic ? Choose all that apply .
H - O - H -> H - O . + . H H - CI : -> H . + CI :
Match the relative enthalpies of reactants and products to the correct change in enthalpy given (Delta)Hreaction = Hproducts - Hreactants
Hreactants > Hproducts <————> (Delta)Hreaction < 0 Hreactants < Hproducts <————> (Delta)Hreaction > 0
Match each description of entropy to the correct symbol or terms .
Low entropy <————> A well - organized system High entropy <————> A random or disordered system S <————> The symbol used to represent the entropy of a substance
Match each term concerning energy and changes in energy to the correct description .
Potential energy <————> Can be in the form of energy stored in bonds Kinetic energy <————> Can be in the form of thermal energy Heat ( flow ) <————> The transfer of thermal energy from a system to the surroundings Calorimetry <————> Experimental method for measuring temperature change and calculating heats of reactions
Match each term to the correct description concerning the equation used in calorimetry : Q = ms x (Delta)Ts x SHs
Q <————> The quantity of heat absorbed or released by the reaction ms <————> The mass of the solution in the calorimeter (Delta)Ts <————> The change in temperature of the solution SHs <————> The specific heat of the solution
Match each term to the correct unit concerning the equation used in calorimetry : Q = ms x (Delta)Ts x SHs
Q <————> cal ms <————> g (Delta)Ts <————> Degrees Celsius SHs <————> cal/g. Degrees Celsius
Match each term to the correct unit concerning the equation used in calorimetry : Q = ms x (Delta)Ts x SHs
Q <————> cal ms <————> g (Delta)Ts <————> degrees Celsius SHs <————> cal/g. Dregrees Celsius
By definition , (Delta)Sreaction =
Sproducts - Sreactants
Substance A has a specific heat of 1.2 calories / g ° C . Substance B has a specific heat of 1.5 calories / g ° C . If both substances are exposed to the same amount of heat , which substance will have a higher temperature ?
Substance A
A calorimeter containing a solution initially with a temperature of 23.3 ° C is used to carry out different chemical reactions . Match the final temperature of each reaction mixture in the calorimeter to the type of reaction or heat transfer that took place .
Tf = 30.5 ° C <————> The heat is released by the reaction . Tf = 19.2 ° C <————> The heat is absorbed by the reaction . The reaction is exothermic . <————> Tf = 32.1 ° C The reaction is endothermic . <————> Tf = 20.5 ° C
