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THSB
    Substances, Chemical Reactions, and Conservation of Matter
            When substances interact to form new substances, the atoms that make up the molecules of the original substances…

Item SB004003: After a chemical reaction occurs, some of the atoms are connected to different atoms than they were in the starting molecules. (This item uses circles to represent atoms.)

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The diagram below shows models of the molecules that make up two different substances. In the diagram, atoms are represented by circles, and the molecules are represented by two or more circles connected to each other. The different colored circles represent different types of atoms.

Which of the following could represent one of the molecules that result from the chemical reaction between these two substances? Why?

  1. Because nothing happens to the structure of the molecules during a chemical reaction.
  2. Because some of the atoms are now connected to different atoms than they were in the starting molecules.
  3. Because the molecules that result from a chemical reaction have to include every type of atom from the starting molecules.
  4. Because new types of atoms are formed during chemical reactions.

 

Pre-Test

Distribution of responses
Answer Choice
Overall
Grades
Gender
Primary Language
 
n = 373		 6–8
n = 373		 9–12
n = 0		 Male
n = 205		 Female
n = 168		 English
n = 346		 Other
n = 27
A.
Because nothing happens to the structure of the molecules during a chemical reaction.
5% 5% NAN% 6% 4% 4% 15%
B.
Because some of the atoms are now connected to different atoms than they were in the starting molecules.
18% 18% NAN% 18% 18% 17% 30%
C.
Because the molecules that result from a chemical reaction have to include every type of atom from the starting molecules.
35% 35% NAN% 39% 31% 36% 26%
D.
Because new types of atoms are formed during chemical reactions.
42% 42% NAN% 38% 47% 43% 30%

Post-Test

Distribution of responses
Answer Choice
Overall
Grades
Gender
Primary Language
 
n = 375		 6–8
n = 375		 9–12
n = 0		 Male
n = 205		 Female
n = 170		 English
n = 347		 Other
n = 28
A.
Because nothing happens to the structure of the molecules during a chemical reaction.
3% 3% NAN% 3% 2% 3% 0%
B.
Because some of the atoms are now connected to different atoms than they were in the starting molecules.
51% 51% NAN% 53% 49% 52% 39%
C.
Because the molecules that result from a chemical reaction have to include every type of atom from the starting molecules.
33% 33% NAN% 33% 34% 32% 43%
D.
Because new types of atoms are formed during chemical reactions.
13% 13% NAN% 11% 15% 13% 18%