genchem 2 (2nd mast) #2

endothermic

Ice cream melting is an example of a/an ___ process.

endothermic

Drying is an _ process because heat is absorbed.

b

Hot coffee in a tumbler with cover:

a. open system

b. closed system

c. isolated system

c

A system absorbs 90 J of heat and its internal energy increases by 40 J. Find W.

a. +130 J

b. -130 J

c. -50 J

d. +50 J

Q

What is the symbol for heat?

True

Enthalpy is in the form of chemical energy.

False

True

False

In an endothermic reaction, the system is releasing energy.

True

False

b

Which process has △H > 0?

a. Freezing water

b. Melting ice

c. Burning methane

d. Condensing steam

c

A system gains 18 J of energy while releasing 12 J of heat. Find work.

a. +6 J

b. -30 J

c. +30 」

d. -6J

Heat

The transfer of thermal energy between objects of different temperatures is:

c

The standard enthalpy of formation of O2(g) is:

a. 25 kJ/mol

b. +241 kJ/mol

c. 0 kJ/mol

d. -241 kJ/mol

c

A system loses 25 J of energy while 10 J of work is done on it. What is Q?

a. -15 J

b. +15 J

c. -35 J

d. +35 J

warm

During an endothermic reaction in a beaker, if we are part of the surroundings and touch the beaker, it would feel __

isolated system

It is a system in which matter and energy cannot transfer between system and surroundings.

c

System loses 15 J of heat and does 5 J of work. △E = ?

a. -10 J

b. +10 J

c. -20 J

d. + 20 J

d

Which statement is true for an isolated system?

a. Only matter is exchanged with surroundings.

b. Energy and matter are exchanged with surroundings.

c. Only energy is exchanged with surroundings.

d. Neither energy nor matter is exchanged with surroundings.

False

The △H value in an endothermic reaction is a negative number.

True

False

a

A gas absorbs 40 J of heat and 20 J of work is done on it. Find △E.

a. 60 J

b. -20 J

c. 20 J

d. -60 J

b

A 30 kJ of heat is absorbed by the system and 100 kJ of work is done on the surroundings. What is the amount of heat in the given problem?

a. -100 kJ

b. +30 kJ

c. +100 kJ

d. -30 kJ

True

If work is compressed, it is a positive work.

False

True

c

Hot milk in a glass:

a. closed system

b. isolated system

c. open system

d

How much heat (in kJ) is released when 1.00 mol of propane combusts, given AH°rxn = -2043.85 kJ/mol?

a. 1021.9 kJ released

b. 4087.7 kJ released

c. 2043.85 kJ absorbed

d. 2043.85 kJ released

b

What is internal energy?

a. It is the amount of heat an object contains.

b. It is the sum of the kinetic and potential energy of the particles.

c. It is the transfer of energy between system and surroundings due to temperature difference.

false

The first law of thermodynamics states that energy is created.

True

False

b

What is the difference between the enthalpy of the products and the reactants?

a. Enthalpy of Transformation

b. Enthalpy of Reaction

c. Enthalpy of Formation

d. Enthalpy of Equation

c

If a chemical reaction has △H°rxn = +120 kJ, which is true?

a. System temperature will increase spontaneously

b. Reaction will always be spontaneous

c. Reaction is endothermic and absorbs 120 kJ

d. Reaction is exothermic and releases 120 kJ

d

A system loses 60 J of heat and has 25 J of work done on it. △Е = ?

a. 85 J

b. +85 J

c. +35 J

d. -35 J

E

What is the symbol for internal energy?

b

A system releases 50 J of heat while 30 J of work is done on it. Find △E.

a. 20 J

b. -20 J

c. -80 J

d. 80 J

d

A 30 kJ of heat is absorbed by the system and 100 kJ of work is done on the surroundings. What is the amount of work in the given problem?

a. +30 kJ

b. -30 kJ

c. -100 kJ

d. +100 kJ

b

The sign of △H is negative for a reaction that is:

a. impossible

b. exothermic

c. endothermic

d. at equilibrium

b

A reaction releases 450 kJ when 3.0 mol of reactant are consumed. Heat released per mole is:

a. -1350 kJ/mol

b. -150 kJ/mol

c. -75 kJ/mol

d. -450 kJ/mol

d

Which statement is true about an endothermic reaction at constant pressure?

a. The surroundings gain heat.

b. No energy transfer occurs.

c. △H is negative.

d. The system absorbs heat.

false

In an exothermic reaction, the system is absorbing energy.

True

False

true

Heat flows from higher temperature to lower temperature.

False

True

b

Heat flows from ___ objects.

a. cooler to warmer

b. warmer to cooler

c. warmer to warmer

d. cooler to cooler

endothermic

Sweat on forehead is an example of:

a

Work is done by the system 40 J, △E = -10 J, find Q.

a. +30 J

b. -50 J

c. +50 J

d. -30 J

d

Heat absorbed 100 J, work done on system 25 J. △E = ?

a. +75 J

b. -125 J

c. -75 J

d. +125 J

False

In a cup of coffee, the surrounding is the coffee.

True

False

thermodynamics

What branch of science deals with the relationship between heat and other forms of energy, particularly transfer of heat into work?

false

In an exothermic process, the surrounding loses heat.

True

False

false

In the equation AE = Q + W, the symbol △ is called omega.

True

False

c

Mary is making a cup of hot coffee. Which is considered the surrounding?

a. exam

b. hot coffee

c. cup

c

Heat absorbed 60 J, work done by system 20 J. △E = ?

a. -80 J

b. -40 J

c. +40 J

d. +80 J

b

When 5.00 g of NH4NO3 dissolves in water, the temperature of the solution decreases. This process is best described as:

a. Exothermic, system releases heat

b. Endothermic, system absorbs heat

c. Endothermic, surroundings absorb heat

d. Exothermic, system absorbs heat

exothermic

Combustion of gasoline is an example of:

system

It is a part of universe on which you focus your attention.

b

The enthalpy change for the decomposition of CaCO2(s) to CaO(s) and CO2(g) is +178 kJ/mol. Which statement is correct?

a. △H is negative.

b. The reaction absorbs heat.

c. The reaction releases 178 kJ/mol.

d. The reaction is exothermic.

exothermic

A reaction is performed in a beaker with a temperature probe recording the temperature changes of the reaction. The temperature began at 15.0 degrees Celsius and ended at 27.5 degrees Celsius. What reaction is done by the system?