AnswersTN-Physical Science SC 26-27 For CreditIntroduction to Chemical Reactions

Introduction to Chemical Reactions Answers

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When vinegar and baking soda react, the mixture becomes cold to the touch and a gas and a new liquid substance are formed.

A
The reaction is chemical and endothermic.
B
The reaction is chemical and exothermic.
C
The reaction is non-chemical and endothermic.
D
The reaction is non-chemical and exothermic.
2
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Pedro wants to create a chemical reaction between oil and water. He adds oil to a beaker of water and notices that the liquids do not mix. He then shakes the beaker and the drops of oil become suspended through the water for a few moments before returning to their separate layers.

A
Yes, because the oil was evenly suspended.
B
Yes, because the solution was permanently changed.
C
No, because the oil only briefly mixed with the water.
D
No, because no new substances were formed.
3

When baking soda and vinegar react, the surface bubbles. What does this most likely indicate?

A
a chemical change, because a precipitate is being formed
B
a chemical change, because a gas is being formed
C
a non-chemical change, because a precipitate is being formed
D
a non-chemical change, because a gas is being formed
4

Which is an example of a chemical reaction?

A
paper folded into tiny pieces
B
paper burned and turned into smoke
C
paper soaked in water
D
paper shredded and turned into pulp
5

Cherylanne mixes together Chemical A and Chemical B in a test tube, forming Chemical C. The mixture instantly turns cool to the touch. She then adds Chemical D, and the reaction becomes hot and explodes.

A
Chemicals A and B form an endothermic reaction, and chemicals C and D form an exothermic reaction.
B
Chemicals A and B form an exothermic reaction, and chemicals C and D form an endothermic reaction.
C
Chemicals A and C form an endothermic reaction, and chemicals B and D form an exothermic reaction.
D
Chemicals A and B form an exothermic reaction, and chemicals B and D form an endothermic reaction.
6

When liquid silver nitrate and liquid sodium chloride are combined, solid silver chloride forms along with a new liquid, sodium nitrate. Which substance represents the precipitate?

A
silver nitrate
B
silver chloride
C
sodium chloride
D
sodium nitrate
7

Reggie and Charlotte are baking oatmeal cookies. They dip the baked cookies in melted chocolate. The chocolate cools to form a hardened coating. Reggie argues the entire chocolate-covered cookie has undergone a chemical change. Charlotte disagrees, saying only the original oatmeal cookie has undergone a chemical change, not the chocolate coating.

A
Reggie, because baking and melting cause bonds to be broken, leading to a chemical change.
B
Reggie, because objects that are heated always undergo chemical changes.
C
Charlotte, because melting objects only sometimes cause a chemical change.
D
Charlotte, because baking causes a chemical change, but melting objects is a non-chemical change.
8

For a science project, Janet performs four experiments that are supposed to show a chemical reaction. She displays her results in a table.

Question illustration
A
Experiment 1
B
Experiment 2
C
Experiment 3
D
Experiment 4
9

Which best describes what happens to the atoms in a chemical reaction?

A
they are rearranged
B
many of them disappear
C
all of them form stronger bonds
D
all of them remain unchanged

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