Transcript Kinetic energy

SCIENCE
Baseline Assessment
Grade
11
Questions 1-15
SC. A-1.4.3
PHASE CHANGE
gain or loss of energy
(Questions 1-2-3)
GAIN ENERGY
(+) energy gain
(-) energy loss
(Questions 4-5-6)
• SC. A-1.4.4
•
•
•
•
RATES of REACTION-depend on
temperature,
pressure,
concentration of reactants,
presence or absence of catalysts
• Temperature of reactants
….as you increase the temperature
the rate of reaction increases.
• Pressure of reactants
• Increasing the pressure on a reaction involving
reacting gases increases the rate of reaction.
• Changing the pressure on a reaction which
involves only solids or liquids has NO effect on
the rate.
• Concentration of reactants
(It’s complicated!)
• For many reactions involving liquids or gases, increasing the
concentration of the reactants increases the rate of reaction.
• In a few cases, increasing the concentration of one of the
reactants may have little noticeable effect of the rate. These
cases are discussed and explained further down this page.
• Don't assume that if you double the concentration of one of
the reactants that you will double the rate of the reaction. It
may happen like that, but the relationship may well be more
complicated.
• Presence or absence of catalysts
• Catalyst present, increases rate of
reaction
• By lowering the activation energy
require for the reaction to occur.
Catalyst- substance that increases the rate of reaction
by lowering the activation-energy barrier
(the catalyst is not used up in the reaction.)
Inhibitor-slows the rate of reaction, can stop reaction
completely.
Activation Energy-the minimum
energy colliding particles must have in
order to react
The spark is the
catalyst and
lowers the
activation energy
required for the
reaction to
happen!
Catalysts may reduce the amount of activation energy required for a chemical reaction to
occur. Platinum (Pt) is a catalyst that is used in catalytic converters in automobiles.
In the graphs below, pathway x is a solid line representing the uncatalyzed reaction. The
dotted line shows the catalyzed reaction. Which graph best illustrates the changes in a
reaction when the catalyst reduces the amount of energy required?
Reactants
Potential Energy /PE
B.
Potential Energy /PE
A.
Products
x
Reaction Rate →
C.
Products
Reactants
x
Reaction Rate →
Reactants
Products
x
Correct answer-D.
Potential Energy /PE
Potential Energy /PE
D.
Activation Energy
lowered. Products
generated are not
increased or decreased.
Reactants
Products
Reaction Rate →
Reaction Rate →
x
SC.A.2.4.5
PERIODIC TABLE
Group (Family) ↓ Periods →
• The periodic table is arranged by atomic number (the
number of protons in an element).
• Each column of elements from the top to the bottom is called a group
(also family). Groups of elements have properties that are alike.
All the elements in a group have the same number of electrons in their
atoms' outer shells. Each group has a letter and a number. All of the
elements in Group 1 have one electron in their atoms' outermost shell
(valence shell).
• The elements going across (row) on the table are called periods. Each
period has a number. The elements in a period have different
properties. All elements in the left-hand side of a period tend to lose
electrons and become positively (+) charged. The atoms of the
elements toward the right side of the period tend to gain electrons.
These elements become negatively (-) charged. All the atoms at the far
right neither gain nor lose electrons. They are stable elements. These
are called Noble Gases (Inert Gases).
SC.B.1.4.1
ENERGY
Energy required for biological processes,
building, erosion, rebuilding of Earth.
Energy is defined as the capacity to do work.
An object has kinetic energy if it is moving. If there are
some constrained or pent-up forces, preventing the object
to move, the object is said to have potential energy.
There are various subsets or forms of both kinetic and
potential energy, such as:
heat, chemical, electrical, light and nuclear energy.
• Kinetic energy (KE)-energy that an object or
particle has because it is moving
• Potential energy (PE)-stored energy that an
object has because of its position or shape
 Thermal energy (Heat energy)-total KE contained in all
particles of a substance.
• Heat energy
•
Heat is the movement of molecules. It is the sum of the kinetic energy of an object's
molecules.
• Electrical energy
•
Electrical energy is the movement of electrons. That is kinetic energy. The voltage in
an electrical circuit is the potential energy that can start electrons moving. Electrical
forces cause the movement to occur.
• Chemical energy
•
Chemical energy is potential energy until the chemical reaction puts atoms and
molecules in motion. Heat energy (KE) is often the result of a chemical reaction.
• Light energy
•
Light is the movement of waves and/or light particles (photons). It is usually formed
when atoms gain so much kinetic energy from being heated that they give off
radiation. This is often from electrons jumping orbits and emitting moving photons.
• Nuclear energy
•
Certain elements have potential nuclear energy, such that there are internal forces
pent up on their nucleus. When that potential energy is released, the result is kinetic
energy in the form of rapidly moving particles, heat and radiation.
1) Clara carries a glass of ice water outside on a hot
day. She sets it down and rushes inside to answer
the phone. When she returns, the ice has melted.
What is the best explanation for what happened to
the drink?
A. The warm air carried convection heat currents,
which melted the ice molecules.
B. The ice molecules passed their cold energy to the water molecules,
resulting in the liquid state.
C. The ultraviolet rays from the Sun heated the ice molecules,
decreasing their kinetic energy and increasing their attraction.
D. The ice molecules absorbed energy from their surroundings,
gained kinetic energy, and overcame the forces holding them
in a solid phase.
2.For most substances, freezing and melting
occur at the same temperature. Which of the
following best explains the difference between
the processes of melting and freezing?
A. When a substance melts, its molecules are slowing down;
when freezing, its molecules are speeding up.
B. When a substance freezes, its molecules move farther
apart; when melting, its molecules come closer together.
C. When a substance melts, its molecules have a decrease in kinetic
energy; when freezing, its molecules have an increase in kinetic energy.
D. When a substance freezes, its molecules release energy;
when melting, its molecules require an input of energy
to change it to a liquid.
3. Mica is sweating after winning his 1OO-meter
race. Which best explains why sweating helps
Mica cool off?
A. The liquid sweat evaporates,
which takes heat energy from his body.
B. The liquid sweat allows conduction of heat from his
body to the air.
C. The sweat allows heat to escape by increasing wind
chill, making his body feel colder.
D. The sweat forms on his skin and allows his
body to adjust its temperature by convection.
4. Bobby is planning to cook some hot dogs using a
charcoal grill. After he lights the charcoal, it burns very
slowly. Bobby's brother suggests blowing on the
charcoal to make it burn faster. Which of the following
explains why his brother's suggestion works?
A. Blowing on the charcoal decreases the temperature of the charcoal.
B. Blowing on the charcoal catalyzes the reaction that causes
the charcoal to burn.
C. Blowing on the charcoal increases the concentration of oxygen
at its surface.
D. Blowing on the charcoal reduces the amount of energy
needed for the charcoal to burn.
5. Oxygen gas (O2) and potassium chloride (KCl) can be
produced in the laboratory by heating solid potassium
chlorate (KCIO:), as shown by the following chemical
reaction:
2KClO3(s)
2KCl(s) + 3O2 (g)
Even with heating, the reaction is rather slow, but it
can be sped up by mixing in some manganese dioxide
(MnO2). T he MnO2 can’t re recovered unchanged after the
reaction. How is MnO2 acting to increase the reaction rate?
A. MnO2 is a catalyst for the reaction.
B. MnO2 adds energy to the reaction.
C. MnO2 decreases the concentration of KClO3.
D. MnO2 provides more oxygen to the reaction.
6. Iron (Fe) is an important catalyst used in the
commercial production of ammonia (NH3).
Which of the following best describes why iron
is used in the reaction to produce ammonia?
A. The iron becomes part of the ammonia product.
B. The iron helps yield higher-quality ammonia.
C. The iron lowers the activation energy needed to produce
ammonia.
D. The iron speeds up the production of ammonia
by increasing the temperature.
7. Sean is studying the periodic table of elements.
What do elements in the same group in the
periodic table have in common?
A. energy levels
B. ionization energy
C. number of protons
D. number of valence electrons
8. Newlands, Meyer, Mendeleev, and Moseley made
contributions to the modem periodic table of elements.
The Periodic Law that exists in the modern periodic
table states that elements show periodic repetition of
their physical and chemical properties when arranged
by a particular property. Elements in the modern
periodic table are arranged by increasing:
A. atomic mass.
B. atomic number.
C. atomic radius.
D. ionization energy.
9. lonization energy is the energy needed !o remove an electron
from an atom. The graph below shows the ionization energy for
the first 20 elements of the periodic table. Which best explains
why the noble gases: Helium (He), Neon (Ne), and Argon (Ar)
have the highest ionization energies?
A. They all have the same electron
configuration.
B. They all have a full set of valence
electrons.
C. They all are very reactive when
added to acidic solutions.
D. They all chemically bond with the
alkali metals to form ionic compounds.
10.Household appliances operate by converting
energy from one form to another. For
example, microwave ovens convert energy in
order to cook food. Which statement
correctly identifies the kind of energy used by
microwave ovens and how it cooks food?
A. Kinetic energy is used to produce solar radiation which
cooks the food.
B. Nuclear energy is used to produce potential energy
which cooks the food.
C. Heat energy is used to produce mechanical
energy which cooks the food.
D. Electric energy is used to produce electromagnetic
radiation which cooks the food.
11. Because nonrenewable resources are in
limited supply, the development of alternative
energy resources is becoming increasingly
important. Which of these describes an energy
conversion that occurs when a renewable
energy resource is used?
A. Kinetic energy is converted to radiant energy as light strikes a solar panel.
B. Potential energy is converted to mechanical energy in a hydroelectric dam.
C. Nuclear energy is converted to potential energy during a fission reaction.
D. Chemical energy is converted to electric energy through the burning of
fossil fuels.
12. Kelly is building a model of a volcano. Her plan
involves combining baking soda and vinegar to simulate
the eruption of the volcano. She tests the reaction in a
glass beaker first. When a small amount of baking soda
and vinegar combine, carbon dioxide is produced, along
with some foam and fizz inside the beaker. How do the
beaker's contents after reaction compare to the
contents before reaction?
A. The mass inside the beaker decreases as carbon dioxide gas leaves the beaker.
B. The mass inside the beaker changes, depending on the type of beaker used.
C. The mass inside the beaker increases, since the products are more dense
than the reactants.
D. The mass inside the beaker stays the same because the total amount of mass can
never change.
EXTRA ENERGY QUESTION:
All organisms on Earth need food to live and grow. These organisms either produce their
own food, via photosynthesis, or eat other organisms according to complex food webs.
The energy that is transferred through these processes can be traced back to what
feature of our universe?
A. the Sun
B. distant planets
C. the water on Earth
D. geothermal atmosphere
EXTRA ENERGY QUESTION:
In order to do work, energy needs to be converted from one form to a more useful
form for the particular task. When someone hammers a nail into a piece of wood,
energy is converted from gravitational potential energy to which more useful form?
A. electromagnetic energy
B. kinetic energy
C. sound energy
D. thermal energy