11.1 Thermochemistry

Multiple Choice

What is collision theory?

• Molecules must collide in the correct orientation with enough energy to bond.

• Molecules need enough energy to collide and react.

• Atoms constantly collide and react.

• The minimum energy needed for atoms to react

Multiple Choice

If the reactant particles collide with less than the activation energy, the particles will be rebound, and no reaction will occur.

• True
• False

Multiple Choice

The unstable cluster of atoms that exists during the transition from reactants to products. 

• Consistent collisions
•  Normal collisions 
• Activated Complex 

• None of the above

Multiple Choice

Heat is the _______ of energy.

• Transfer
• Measure

Multiple Choice

Temperature is the ________ of energy.

• Transfer
• Measure

Multiple Choice

Which choice below deals with how fast the particles of an object move?

• Heat
• Temperature

Multiple Choice

Heat transfer occurs (Heat travels from...)

• in many directions.

• both from warm objects to colder ones and from cold objects to warmer ones.

• only from warm objects to colder ones.

• only from cold objects to warmer ones.

Multiple Choice

When ice is dropped into warm cup of water, it begins to melt. What is the system?

• Water and Ice

• Cup

• Water

• Ice

Multiple Choice

The SI unit of heat and energy is the __________.

• calorie
• heat
• joule
• watt

Multiple Choice

ΔH value in an endothermic reaction is a positive number.

• True
• False

Multiple Choice

Which statement is true regarding endothermic reactions?

• a) Temperature change is positive and enthalpy change is positive
• b) Temperature change is positive and enthalpy change is negative
• c) Temperature change is negative and enthalpy change is positive
• d) Temperature change is negative and enthalpy change is negative

Multiple Choice

Endothermic reactions feel

• warm
• cold

Multiple Choice

A reaction that gives out energy to the surroundings causes the surroundings ....

• temperature to drop

• temperature to rise

• temperature to remain constant

• temperature to vary

Multiple Choice

The enthalpy change is a negative (-) value, what side of the equation will the energy value be on.

• Reactants

• Products

Multiple Choice

In the reaction picture, the energy will be on product or reactant

• Product

• Reactant

Multiple Choice

What type of reaction is shown in the reaction pathway?

• endothermic reaction

• exothermic reaction

Multiple Choice

What is the activation energy?

• The energy of the products
• The energy of the reactants
• The minimum energy needed by the reactants to form the products.
• The energy lost in the reaction

Multiple Choice

What is the potential energy of the reactants?

• 10 kJ
• 45 kJ
• 103 kJ
• 58 kJ

Multiple Choice

What is the potential energy of the products?

• 10 kJ
• 45 kJ
• 103 kJ
• 58 kJ

Multiple Choice

What is the ΔH of the reaction?

• 35 kJ
• - 35 kJ
• - 58 kJ
• 58 kJ

Multiple Choice

Which letter corresponds to the activation energy of the forward reaction?

• A
• B
• C
• D

Multiple Choice

Which letter corresponds to the energy of the reactants?

• A
• B
• C
• D

Multiple Choice

Which letter corresponds to the energy of the products?

• A
• B
• C
• D

Multiple Choice

Which letter corresponds to the energy of the activated complex?

• A
• B
• C
• D

Multiple Choice

Which letter corresponds to the ΔH of the reaction?

• F
• E
• C
• D

Multiple Choice

Which letter corresponds to the energy of the products?

• B
• C
• F
• E

Multiple Choice

Using the equations below:

C(s) + O₂(g) → CO₂(g) ∆H = –390 kJ

Mn(s) + O₂(g) → MnO₂(s) ∆H = –520 kJ

what is ∆H (in kJ) for the following reaction?

MnO₂(s) + C(s) → Mn_(s) + CO₂(g)

• 910

• 130

• -130

• -910

Multiple Choice

Consider the following equations.

Mg(s) + O₂(g) → MgO(s) ∆H = –602 kJ

H₂(g) + O₂(g) → H₂O(g) ∆H = –242 kJ

What is the ∆H value (in kJ) for the following reaction?

MgO(s) + H₂(g₎ → Mg(s) + H₂O(g)

• -844

• -360

• +360

• +844

Multiple Choice

Can result from adding or removing thermal energy

• explosion
• change of conservation
• change of state of matter
• Change of Newton's law

Multiple Choice

The change of state from a gas to a liquid

• condensation
• deposition
• evaporation
• sublimation

Multiple Choice

Temperature at which matter changes from liquid to solid

• freezing point
• melting point
• boiling point
• absolute zero

Multiple Choice

How many calories are required to boil 75 grams of water?
(not in sig figs)  H_f = 80.0 cal/g,  H_v = 560.0 cal/g, S_H = 1.00 cal/g ºC

• 6,000 cal
• 3,360,000 cal
• 42,000 cal
• 7.46 cal

Multiple Choice

Stored energy resulting from the interactions between particles or objects

• kinetic energy
• mechanical energy
• potential energy
• thermal energy

Multiple Choice

Calculate the amount of energy required to melt 35.0 grams of ice.
(not in sig figs)  H_f = 80.0 cal/g,  H_v = 560.0 cal/g, S_H = 1.00 cal/g ºC

• 19,600 cal
• 35.0 cal
• 2,800 cal 
• 1,568,000 cal