Name
Date
Class
Matter and Energy
8.5(E) readiness
Choose the best answer for each question. Circle the letter for the correct
answer or bubble the answer in the provided griddable.
1 Jack read that the application of heat can cause sucrose to decompose
into carbon and water. The chemical equation that shows this reaction is
Explain your choice.
C12H22O11 + heat → 12C + 11H2O
To investigate that the chemical reaction formed new substances, Jack
reviewed the laboratory safety procedures and then heated a small amount
of sugar. What observation indicated the formation of a new substance?
A The heat that was applied turned the water that was released into ice.
B The heat, when taken away from the reaction, turned the carbon
into water.
C The white sucrose crystals, when heated, turned into a black mass
of carbon.
Copyright © McGraw-Hill Education. Permission is granted to reproduce for classroom use.
D The white sucrose crystals, when heated, turned into a yellowish
liquid of glucose.
2
Judy investigates the use of a stomach antacid. An antacid pill
contains solid calcium carbonate (CaCO3). She discovers that when
the calcium carbonate enters the system it reacts with the liquid
hydrochloric acid (HCl) found in the stomach. Judy’s investigation
shows the equation:
Explain your choice.
CaCO3 + 2HCl → CaCl2 + H2O + CO2
She reads the caution label on the medicine and notes that taking
the tablet can cause the release of gas in the digestive tract.
What in Judy’s investigation indicates evidence of a chemical reaction
producing a new substance with different properties?
F A solid tablet reacted with a liquid to form three products with
different properties.
G A solid tablet reacted with a liquid to form three products with
the same properties.
H Solids like calcium carbonate and liquids like hydrochloric acid
do not chemically react.
I The solid went through a phase change to a liquid and then to a
gas in the stomach.
Matter and Energy TEKS 8.5(E)
41
Matter and Energy
Name
Date
Class
8.5(E) readiness
Explain your choice.
3 Julio wants to investigate evidence of a chemical reaction that indicates
new substances are formed with different properties. To do this, he runs
a computer simulation of the reaction of nitrogen (N2) and hydrogen
(H2) to form ammonia (NH3).The computer program reviewed safety
procedures that would be followed if this were an actual laboratory
investigation. He then notes that the equation for the reaction is
N2 + 3H2 → 2NH3
Which statement indicates that a chemical reaction has occurred?
A The atoms of hydrogen and nitrogen have rearranged to form a new
substance, ammonia, with different chemical properties.
B The atoms of hydrogen and nitrogen have rearranged to form a new
substance, ammonia, with the same chemical properties.
C The reaction shows nitrogen and hydrogen each have two atoms
per molecule and ammonia has four atoms per molecule.
D There is more hydrogen molecules than nitrogen molecules needed
to complete the chemical reaction.
4 Matt and Charlie worked together to study a double-replacement
chemical reaction. After reviewing and agreeing to safety policies, they
poured 10 mL of clear, colorless barium chloride solution into a clean
dry test tube. They then added 10 mL of clear, colorless sodium sulfate
solution to the barium chloride solution. Upon mixing the two chemicals
they noted that the solution turned milky white and eventually a white
solid settled to the bottom of the test tube. How did they explain what
they had observed?
F Heating the reactants will cause clear, colorless solutions to change
to a milky white solution.
G The reactants rearranged to form a milky white gas that eventually
settled to the bottom of the test tube.
H The reactants rearranged to form a milky white solid that settled to
the bottom of the test tube.
I The reactants rearranged to form a product that was very cold and
turned to ice.
42
Matter and Energy TEKS 8.5(E)
Copyright © McGraw-Hill Education. Permission is granted to reproduce for classroom use.
Explain your choice.
Name
Date
Class
Matter and Energy
8.5(E) readiness
5 Emily is studying chemical reactions in science class. During a
laboratory experiment, she completes a series of procedure steps. She
thinks that some of the steps results in a chemical reaction. How can
she determine if a chemical reaction has taken place?
Explain your choice.
A She should study the chemical properties of the products after
the reaction.
B She should study the chemical properties of the reactants and
products before and after the reaction.
C She should study the physical properties of the products after
the reaction.
Copyright © McGraw-Hill Education. Permission is granted to reproduce for classroom use.
D She should study the physical properties of the reactants and
products before and after the reaction.
6 A scientist is investigating a water supply system. She is concerned
about the presence of chlorine used for water purification. She knows
that the presence of chlorine can be detected by adding a few drops
of silver nitrate to a sample of the water. She prepares three samples to
test. Sample number one contains pure distilled water. Sample number
two contains pure distilled water with chlorine. Sample number three is
the water from the water supply system. She added a few drops of silver
nitrate solution to each sample. If the chlorine is present in the water
supply system, what will the scientist observe?
Explain your choice.
F Samples number one and two will turn milky white and sample
number three will remain colorless.
G Sample number one will remain colorless and samples two and
three turn milky white.
H Sample number three will turn milky white and samples numbered
one and two will remain colorless.
I Sample number two will turn milky white and samples numbered
one and three will remain colorless.
Matter and Energy TEKS 8.5(E)
43
Matter and Energy
Name
Date
Class
8.5(E) readiness
Explain your choice.
7 Bill asked his teacher to allow him to investigate and demonstrate a
chemical reaction. He first reviews safety policies and the suggestions
for proper disposal of the materials. Bill wants to add liquid vinegar,
chemically known as acetic acid, to solid baking soda, drop by drop,
and observe the results. His research shows him that baking soda has
the chemical formula NaHCO3 and that the formula for acetic acid is
HC2H3O2. He continues his research and finds the chemical equation
for the reaction.
NaHCO3 + HC2H3O2 → NaC2H3O2 + H2O + CO2
Bill then adds the vinegar, drop by drop, to the baking soda and notices
that bubbles form. Which evidence does Bill’s investigation indicate that
a chemical reaction formed a new substance with new properties?
A The bubbles indicate that a new substance, a gas, is formed.
B The bubbles indicate that the reaction is boiling, forming a new
substance.
C The bubbles indicate that the vinegar is absorbing air, forming a new
substance.
D Vinegar has a pungent odor and baking soda is an odorless solid.
44
Matter and Energy TEKS 8.5(E)
Copyright © McGraw-Hill Education. Permission is granted to reproduce for classroom use.
Check your answers.
If you missed 0-1, great job!
If you missed 2-3, not bad.
If you missed 4-7, review the evidence of a chemical reaction.