Science Assessment ~ Items ~ SC043005

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A student places some baking soda and a jar of lemon juice in a plastic bag and seals the bag. She weighs the bag and everything in it. She shakes the bag so that the lemon juice spills out of the jar and mixes with the baking soda inside the bag. The student observes that bubbles form, and the bag expands.

If the student weighs the bag and everything in it after the bubbling stops and compares the final weight to the starting weight, what will she find out?

The final weight will be greater than the starting weight because new atoms are produced during the experiment.
The final weight will be less than the starting weight because some of the atoms are destroyed during the experiment.
The final weight will be the same as the starting weight because the number of each kind of atom does not change during the experiment.
The final weight will be the same as the starting weight because some atoms are destroyed, but new ones are created during the experiment.

Details
Performance
NGSS

Topic: Substances, Chemical Reactions, and Conservation of Matter
Correct Answer: C
Misconceptions
Other Projects: THSB

Distribution of Responses

Chart showing distrubtion of responses for Item SC043005

Students Responding Correctly

Group	Correct	Total	Percent
Overall	1004	2847	35%
Grades
6–8	440	1624	27%
9–12	562	1215	46%
Gender
Male	532	1404	38%
Female	460	1390	33%
Primary Language
English	877	2465	36%
Other	103	323	32%

View data table

Disciplinary Core Ideas: PS1.B Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.
PS1.B The total number of each type of atom is conserved, and thus the mass does not change.

Science Assessment

Item SC043005: When baking soda and lemon juice react in a sealed plastic bag, the weight will not change because the number of each kind of atom does not change.