Bell Ringer - MR. DEAN'S SCIENCE PORTAL...Bell Ringer Read the article: “7 things you may not know...
Transcript of Bell Ringer - MR. DEAN'S SCIENCE PORTAL...Bell Ringer Read the article: “7 things you may not know...
Bell RingerRead the article: “7 things you may
not know about catalysis”
Using the red pens, underline any
words you do not know.
Time Limit: 10 mins
Answer the following questions
1. Name 4 things mentioned in the article that use a catalyst.
2. What is a catalyst and how does it affect a chemical
reaction?
3. Describe the basics of how a lithium-air battery works as
mentioned in the article.
4. What do you already know about catalysts from biology
last year?
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Reaction Rates
Chemical reaction rates depend on factors
that influence the frequency of collision of
reactant molecules.
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Objective 1Define and describe reaction rate and how it is
affected by different factors.
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As the reactant amount decreases and product amount
increases in concentration as time progresses.
Reaction Rate
Reactants Productsreactants
products
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2H2 + O2 2H2O
A. an increase in the concentration of O2
and H2 with time
B. an increase in the concentration of
H2O with time
C. an increase in H2 and O2 with time
D. a decrease in H2O with time
Which of these describes the rate of the above
chemical reaction?
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The rate of a reaction is measured by
calculating change in:
A concentration
B pressure
C temperature
D volume
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Objective 2
Determine qualities and factors that will
change rates of a reaction
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Qualities that change the
reaction rate:
1. Concentration
2. Temperature
3. Pressure
4. Surface Area
5. Catalyst Addition
The more collisions
between the reactants
molecules the faster the
reaction will proceed.
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#1 Concentration
Changes in concentration will change the rate of reaction.
Increase the concentration the reaction will proceed faster.
Decrease the concentration the reaction will proceed slower or stop.
Higher concentration = greater the rate of reaction
High Low
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#2 Temperature
A change in temperature will change the rate of reaction. When you raise the temperature, the frequency of the collisions increases.
INCREASE IN TEMP = INCREASE IN REACTION RATE
DECREASE IN TEMP = DECREASE IN REACTION RATE
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#3 Pressure
Increasing Pressure
Increasing pressure causes more collisions to occur.
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#4 Surface Area
Example: Diced chicken cooks faster than an entire chicken
breast
• The more surface area a reaction has the faster the
reaction will proceed.
• The less surface area a reaction has the slower the
reaction will proceed.
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#5 Catalyst Addition
A catalyst increases
the rate of a reaction
by lowering the
activation energy of a
chemical reaction. It
will then emerges from
the reaction in the
same form as it was
before the reaction.
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A catalyst LOWERS the activation energy.
Activation energy is the energy needed to make
the reaction occur.
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Catalyst Addition
lowers the Activation
Energy of the Reaction
Ea = Activation Energy
Gas molecules X and O react to form new molecules
at standard temperature and pressure (STP). Which
diagram shows where the greatest rate of reaction
will most likely occur?
**Discuss
with
group**
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Higher temperatures will
A. decrease the amount of products in a chemical
reaction.
B. decrease the concentration of products in a
chemical reaction.
C. increase the reaction rate of a chemical reaction.
D. increase the activation energy of a chemical
reaction.
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2H2(g) + O2(g) 2H2O(l)
A Decrease temperature
B Increase volume
C Increase pressure
D Decrease concentration
In the chemical reaction below, hydrogen gas reacts
with oxygen gas to create water. How can the reaction
rate be increased?
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Which of the following would not have an
effect on the rate of a reaction?
A. concentration
B. temperature
C. pressure
D. specific heat
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How does a catalyst affect reaction rates?
A. It decreases the reaction
rate of a chemical reaction.
B. It increases the reaction rate
of a chemical reaction.
C. It shifts the equilibrium
constant of a chemical
reaction to the left.
D. It shifts the equilibrium
constant of a chemical
reaction to the right.
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How does a catalyst usually emerge
from a reaction?
A. In a decrease concentration after
the reaction.
B. As a different molecule than it
was before the reaction.
C. In a different phase than it was
before the reaction.
D. In the same form as it was before
the reaction. No change in form.
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Which potential energy diagram best
shows how a catalyst affects a chemical
reaction?
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Exit Slip
Clear your desk and prepare for the exit
slip.
This activity is to be done completely on
your own.
You are to answer every question!!!
Let’s aim for mastery of these objectives
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#1 This reaction occurs more quickly when
powdered iron is used instead of a single piece of
iron of the same mass because the powdered iron:
A. Acts as a better catalyst than the single piece of
iron
B. Absorbs less energy than the single piece of iron
C. Has a greater surface area than the single piece
of iron
D. Is more metallic than the single piece of iron
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Fe + 2 HCl 1 FeCl2 + 1 H2
#2 If the reaction below takes place inside a sealed
reaction chamber, then which of these procedures
will cause a decrease in the rate of reaction?
A. Adding more CO to the reaction chamber
B. Raising the temperature of the reaction chamber
C. Removing the CO2 as it is formed
D. Increasing the volume inside the reaction
chamber
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2CO + O2 2CO2
#3 Zinc commonly reacts with hydrochloric acid to
produce salt and hydrogen gas. What could you do
to decrease the reaction rate of the chemical
reaction?
A. Heat the mixture to a hotter temperature
B. Use large chunks of zinc instead of powder
C. Increase the pressure on the zinc
D. Increase the concentration of the acid used
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#4 H2O2, hydrogen peroxide, naturally breaks down into
H2O and O2 over time. MnO2, manganese dioxide, can
be used to lower the energy of activation needed for this
reaction to take place and, thus, increase the rate of
reaction.
What type of substance is MnO2?
A. A catalyst
B. An enhancer
C. An inhibitor
D. A reactant
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