32 terms

Chem B U3 QZ QC

STUDY
PLAY
A piece of metal is heated, then submerged in cool water. Which statement below describes what happens?
The temperature of the water will increase and the temperature of the metal will decrease
Which of the following is NOT a form of energy?
pressure
A process that absorbs heat is a(n)
endothermic process
How many joules are in 148 calories? (1 cal = 4.18 J)
619 J
Which of the following has the greatest heat capacity?
1000 g of water
How does a calorie compare to a joule?
A calorie is larger than a joule
In an exothermic reaction, the energy stored in the chemical bonds of the reactants is
greater than the energy stored in the bonds of the products
The quantity of heat required to change the temperature of 1 g of a substance by 1°C is defined as
specific heat
By what quantity must the heat capacity be divided to obtain the specific heat of that material?
its mass
On what principle does calorimetry depend?
law of conservation of energy
Hess's law
makes it possible to calculate ΔH for complicated chemical reactions
Using a table that lists standard heats of formation, you can calculate the change in enthalpy for a given chemical reaction. The change in enthalpy is equal to
ΔH0f of products minus ΔH0f of reactants
Calculate ΔH for the reaction of sulfur dioxide with oxygen.

2SO2(g) + Os(g) --> 2SO3(g)
(ΔH^0fSO2(g) = -296.8 kJ/mol; ΔH^0fSO3(g) = -395.7 kJ/mol)
-197.8 kJ
Which expression represents a reaction rate?
number/time
Another name for the activated complex is
transition state
Why does a higher temperature cause a reaction to go faster?
There are more collisions per second and the collisions are of greater energy
What happens to a catalyst in a reaction?
It is unchanged
Which of the following substances act a catalysts in the body?
enzymes
At equilibrium, what is the rate of production of reactants compared with the rate of the production of products?
the same
If sulfur dioxide and oxygen can be made into sulfur troxide, what is the reverse reaction?
2SO3 --> 2SO2 + O2
Consider the reaction N2(g) + 3H2(g) <--> 2NH3(g). What is the effect of decreasing the volume on the contained gases?
The reaction shifts toward the product gas
In an endothermic reaction at equilibrium, what is the effect of raising the temperature?
The reaction makes more products
What is the equilibrium constant in the following reaction?
C + O2 <--> CO2
[CO2]/[C][O2]
Activation energy is
the energy barrier between reactants and products
The rate of a chemical reaction normally
increases as reactant concentration increases
What is the effect of adding more water to the following equilibrium reaction?
CO2 + H2O <--> H2CO3
More H2CO3 is produced
If the reaction has an equilibrium constant greater than 1, what type of reaction is it?
reversible, favoring products
The energy that is available to do work in a reaction is called
free energy
Which physical state of nitrogen has the highest entropy?
gas
The two factors that determine whether a reaction is spontaneous or nonspontaneous are
entropy and energy
Which of the following statements is true?
All spontaneous processes release free energy
Which variable is NOT required to calculate the Gibbs free-energy change for a chemical reaction?
temperature in °C
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