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Endothermic/Exothermic
Reaction Rate
Equilibrium
Potential Energy Diagrams
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100
After Jimmy placed raw potato slices and hydrogen peroxide in a plastic bag, he concluded that an exothermic reaction had taken place. Which of the following supports Jimmy’s conclusion?
It felt warm
100
The rate at which a reaction occurs depends on the collisions between the molecules in the reactants. Which best describes the result of a temperature increase on the collisions of the molecules? A. The molecules are compressed, which decreases the number of collisions. B. The number of molecules increases, which increases the frequency of collisions. C. The molecules move faster, which increases the energy released by the collisions. D. The surface area of the molecules increases, which makes the collisions more effective.
C. The molecules move faster, which increases the energy released by the collisions.
100
How does increasing the temperature of an endothermic gas state reaction without changing the pressure affect the equilibrium?
Shift right
100
Pepsin is an enzyme that acts in the stomach for protein digestion. Which of these is most likely the main role of pepsin in this metabolic reaction?
speeds up the rate of reaction
100
Which change increases the rate of a chemical reaction? A increasing the reaction temperature B using larger particles of solid reactants C reducing the concentration of the reactants D adding an inhibitor to the reaction mixture
A Increasing the reaction temperature
200
Two chemicals are mixed in a test tube and a chemical reaction takes place. If this reaction is endothermic and the test tube is touched, which of the following best describes what is felt?
Feels cold
200
Which of these conditions is most likely to increase the rate of interaction among atoms and molecules? A presence of a catalyst B decrease in temperature C low concentration D increase in particle size
A: presence of a catalyst
200
Why is chemical equilibrium considered to be a dynamic state? A.The concentrations of reactants and products are constantly changing. B. The direction of the reaction continually reverses at a constant rate. C. The reaction proceeds in the forward and reverse directions at the same rate. D.The ratio of reactants and products varies depending on the reaction conditions.
C. The reaction proceeds in the forward and reverse directions at the same rate.
200
In each reaction, the temperature and concentration of the reactants was the same. Explain the reduction in the activation energy for Reaction 2?
a catalyst was added
200
A reaction occurs between two gases when they are mixed. Which is the most likely effect on reaction rate if the gases are mixed at the same temperature but at higher pressure? A. Reaction rate increases because the molecules collide more often. B. Reaction rate increases because the molecules collide with more force. C. Reaction rate decreases because the molecules have less room to move. D. Reaction rate stays the same because the molecules move at the same speed.
Reaction rate increases because the molecules collide more often
300
Two chemicals are mixed together in a beaker that is sitting in an ice water bath. The ice in the water melts as the chemicals react for one minute. What type of reaction is taking place?
Exothermic
300
Which stress will increase the production of NO(g) in this equilibrium reaction? 4NH3(g) + 5O2(g) <--> 4NO(g) + 6H2O
add NH3 or add O2 or remove H2O
300
Which of the following must be true if a chemical reaction is at equilibrium? A. The chemical reaction is exothermic. B. The chemical reaction is reversible. C. The products have more energy than the reactants. D. All of the reactants are soluble in water.
B. The chemical reaction is reversible.
300
Describe how Reaction 1 and Reaction 2 are different from each other?
Ms. D will read each answer
300
Marsha and Nathan measure how fast an antacid tablet reacts in water at 30°C. They repeat the experiment after crushing the tablet. They conclude that the tablet produces gas bubbles much faster when it is crushed. Why does the reaction take less time when the tablet is crushed? A. increased surface area of the reactants B. decreased volume of the reactants C. increased kinetic energy of the reactants D. decreased vapor pressure of the reactants
A. increased surface area of the reactants
400
A first aid instant cold pack is an example of a _________ reaction.
Endothermic
400

Solid zinc powder reacts with liquid sulfuric acid. Zn(s) + H2SO4 --> Zn2SO4 + H2 How would stirring the reactants as they are combined affect the rate of reaction? Why?

Stirring will increase the reaction rate. Stirring will allow more atoms come in contact with the solvent.
400
Which reaction, when at equilibrium, would be unaffected by a change in pressure? A N2(g) +O2(g) <--> 2NO(g) B N2O4(g) <--> 2NO2 C CO(g) + O2(g) <--> 2CO2(g) D COBr2 (g) <--> CO(g) + Br2(g)
A N2(g) +O2(g) <--> 2NO(g)
400
What does the line indicated by the letter A in the diagram below refer to?
Activation energy
400
How will increasing the pressure on the system affect this equilibrium reaction? AgCl(s) <--> Ag+(aq) + Cl-(aq)
No shift
500
When heat or energy is a product the reaction is an __________ reaction.
Exothermic
500
Equal masses of steel wool are placed in four beakers. 

Equal amounts of hydrochloric acid (HCl) are added to three beakers in the following concentrations: 

0.5 M, 1.0 M, and 3.0 M. 

Water is added to the fourth beaker. 

HCl reacts with the metal in steel wool. Which beaker will have the fastest reaction?

What is the beaker with the 3.0 M solution?
500
What happens when a chemical reaction reaches equilibrium? A. The amounts of reactants and products remain constant because the reaction stops. B. The rate of the forward reaction is the same as the rate of the reverse reaction. C. The reaction stops because the concentration of reactants is too low to sustain it. D. The reaction reverses so some of the products are converted back into reactants.
B. The rate of the forward reaction is the same as the rate of the reverse reaction.
500
What increases the activation energy?
Inhibitor
500
Two gases chemically react when they are mixed with each other. Equal masses of each gas are placed in a sealed chamber. Which change to the reaction chamber will most likely increase the reaction rate of the gases? A. adding an inert gas to the chamber B. reducing the volume of the chamber C. increasing the surface area of the chamber D. reducing the temperature inside the chamber
Reducing the volume of the chamber