Chapter 17 ReviewChapter 17 Review“Thermochemistry”“Thermochemistry”

Chapter 17 ReviewChapter 17 Review What would likely happen (how What would likely happen (how

would it feel) if you were to touch the would it feel) if you were to touch the flask in which an flask in which an endothermic endothermic reactionreaction were occurring? were occurring?

Standard conditionsStandard conditions of temperature of temperature and pressure for a thermochemical and pressure for a thermochemical equation are __ and __kPa.equation are __ and __kPa.

What is the definition for What is the definition for heat of heat of solutionsolution??

oC

Chapter 17 ReviewChapter 17 Review Hess’s lawHess’s law makes it possible to ___. makes it possible to ___. If heat is If heat is releasedreleased by a chemical by a chemical

system, an equal amount of heat will system, an equal amount of heat will be ____.be ____.

By what quantity must the By what quantity must the heat heat capacitycapacity (J/ (J/ooC) of an object be C) of an object be divided to obtain the specific heat divided to obtain the specific heat (J/g(J/gooC) of that material?C) of that material?

Chapter 17 ReviewChapter 17 Review The symbol stands for the ____.The symbol stands for the ____. When energy is When energy is changedchanged from one form from one form

to another, ____.to another, ____. What happensWhat happens to the energy produced to the energy produced

by burning gasoline in a car engine?by burning gasoline in a car engine? How can the enthalpy change be How can the enthalpy change be

determineddetermined for a reaction in an aqueous for a reaction in an aqueous solution?solution?

H f0

Chapter 17 ReviewChapter 17 Review A process that A process that absorbs heatabsorbs heat is is

called a(n) ____ process.called a(n) ____ process. What does the symbol What does the symbol ΔΔHH stand stand

for?for? During a During a phase changephase change, the , the

temperature of a substance ____.temperature of a substance ____. The amount of heat needed The amount of heat needed to meltto melt

one mole of a solid at a constant one mole of a solid at a constant temperature is called ____.temperature is called ____.

Chapter 17 ReviewChapter 17 Review Using a table that lists standard Using a table that lists standard

heats of formation, you can heats of formation, you can calculate the change in enthalpy for calculate the change in enthalpy for a given chemical reaction. The a given chemical reaction. The change is equal tochange is equal to ____. ____.

A piece of metal is heated, then A piece of metal is heated, then submerged in cool water. The submerged in cool water. The temperature of the watertemperature of the water ____ and ____ and the the temperature of the metaltemperature of the metal ____. ____.

Chapter 17 ReviewChapter 17 Review The amount of heat released by the The amount of heat released by the

complete complete burningburning of 1 mole of a of 1 mole of a substance is the ____.substance is the ____.

The The ΔΔHHsolnsoln is a value that is ____. is a value that is ____. In an exothermic reaction, the In an exothermic reaction, the

energy storedenergy stored in the chemical bonds in the chemical bonds of the reactants is ____ than the of the reactants is ____ than the energy stored in the bonds of the energy stored in the bonds of the products.products.

Chapter 17 ReviewChapter 17 Review The amount of heat involved in the The amount of heat involved in the

synthesis synthesis of 1 mole of compound of 1 mole of compound from its elements, with all from its elements, with all substances in their standard states substances in their standard states at 25 at 25 ooC, is called ____.C, is called ____.

Which of the following substances Which of the following substances has the has the highest specific heathighest specific heat: : a) alcohol, or b) water?a) alcohol, or b) water?

Chapter 17 ReviewChapter 17 ReviewOn what principle does On what principle does

calorimetry calorimetry depend?depend?The specific heat capacity of The specific heat capacity of

graphite is 0.71 J/g graphite is 0.71 J/g ooC. C. Calculate the energyCalculate the energy required to required to raiseraise the temperature of 450 g of the temperature of 450 g of graphite by 16 graphite by 16 ooC.C.

Chapter 17 ReviewChapter 17 ReviewConsider a 79 g chunk of ice Consider a 79 g chunk of ice

((ΔΔHHfusfus = 6.0 kJ/mol) in a beaker = 6.0 kJ/mol) in a beaker

immersed in a water bath. To immersed in a water bath. To produce just enough produce just enough heat to meltheat to melt the ice, how many moles of solid the ice, how many moles of solid NaOH (NaOH (ΔΔHHsolnsoln = -445.1 kJ/mol) = -445.1 kJ/mol)

must you dissolve in the water must you dissolve in the water bath?bath?

Chapter 17 ReviewChapter 17 ReviewA 25.0 g piece of copper wire A 25.0 g piece of copper wire

is heated, and the is heated, and the temperature of the wire temperature of the wire changes from 29.0 changes from 29.0 ooC to 86.0 C to 86.0 ooC. The amount of heat C. The amount of heat absorbed is 343 cal. What is absorbed is 343 cal. What is the the specific heatspecific heat of copper? of copper?

Chapter 17 ReviewChapter 17 Review Use the information below to Use the information below to calculate calculate

ΔΔHHoo for the reaction. for the reaction.

Target equation: 2NOTarget equation: 2NO2(g)2(g) → N → N22OO4(g)4(g)

Given equations:Given equations:

NN2(g)2(g) + 2O + 2O2(g)2(g) → 2NO → 2NO2(g)2(g) ΔΔHHoo = 67.7 kJ = 67.7 kJ

NN2(g)2(g) + 2O + 2O2(g)2(g) → → NN22OO4(g)4(g) ΔΔHHoo = 9.7 kJ = 9.7 kJ

Chapter 17 ReviewChapter 17 Review How much heatHow much heat is required to is required to raise raise

the temperature of 6.5 x 10the temperature of 6.5 x 1022 g of g of aluminum by 30 aluminum by 30 ooC? (specific heat C? (specific heat of aluminum = 0.21 cal/g of aluminum = 0.21 cal/g ooC)C)

How many joulesHow many joules are there in 125 are there in 125 calories? (1 cal = 4.184 J)calories? (1 cal = 4.184 J)

How much heat is required How much heat is required to meltto melt 4.6 mol of NaCl (4.6 mol of NaCl (ΔΔHHfusfus = 30.2 = 30.2 kJ/mol) at its melting point?kJ/mol) at its melting point?

Chapter 17 ReviewChapter 17 Review It takes 470 joules of energy to raise It takes 470 joules of energy to raise

the temperature of 50.0 g of mercury the temperature of 50.0 g of mercury by 90 by 90 ooC. What is the C. What is the specific heatspecific heat of mercury?of mercury?

A substance releases 296 kJ of heat A substance releases 296 kJ of heat as 1.60 mol as 1.60 mol condensescondenses from a gas from a gas into a liquid. What is the into a liquid. What is the molar heat molar heat of of vaporizationvaporization of the substance? of the substance?

Chapter 17 ReviewChapter 17 ReviewWhen 34.0 g of methanol When 34.0 g of methanol (CH(CH33OH) is burned, 954 kJ OH) is burned, 954 kJ

of energy is produced. of energy is produced. What is the What is the heat of heat of combustioncombustion (in kJ/mol) for (in kJ/mol) for methanol?methanol?

Chapter 17 ReviewChapter 17 Review A certain substance with a molar A certain substance with a molar

mass of 43 g/mol has a heat of mass of 43 g/mol has a heat of fusion of 28 cal/g. fusion of 28 cal/g. How many How many caloriescalories are needed to melt 5.2 kg of are needed to melt 5.2 kg of the substance?the substance?

If 150 g of iron absorbs 2,000 cal of If 150 g of iron absorbs 2,000 cal of heat, what will be the heat, what will be the change in change in temperaturetemperature? (specific heat of iron ? (specific heat of iron = 0.11 cal/g = 0.11 cal/g ooC)C)

Chapter 17 ReviewChapter 17 Review If you supply 36 kJ of heat, how If you supply 36 kJ of heat, how

many moles of ice at 0 many moles of ice at 0 ooC can be C can be melted, heated to its boiling point, melted, heated to its boiling point, and completely boiled awayand completely boiled away??

Use the following information:Use the following information:

ΔΔHHvapvap = 40.5 kJ/mol = 40.5 kJ/mol

Specific heatSpecific heatwaterwater = 0.0753 kJ/mol = 0.0753 kJ/mol ooCC

ΔΔHHfusfus = 6.0 kJ/mol = 6.0 kJ/mol

Chapter 17 ReviewChapter 17 Review