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WorksheetsGrade 7 Chemistry
Total questions: 18
Worksheet time: 12mins
When vinegar and baking soda are combined, bubbles begin to form. Explain how the formation of bubbles is evidence of a chemical reaction.
Bubbles are cool.
Bubbles are evidence of a chemical reaction because they indicate that a solid was formed.
Bubbles are REALLY cool
Bubbles are evidence of a chemical reaction because they indicate that gas was formed.
Scenario: When Juan got home from school, he noticed a foul smell coming from the kitchen. He decided to investigate the smell and found fruit sitting on the counter. There was evidence that a chemical reaction had occurred. When he looked at the fruit, he saw that it had turned brown and was soft to the touch.
Question: What is EVIDENCE that supports the claim that a chemical reaction took place?
It looked gross.
It changed color, smelled bad, and turned soft.
It did not taste good.
It smelled bad and turned soft.
Which of the following is the best description of the results of a chemical reaction?
A new substance with different properties is formed
The substance seems to disappear after dissolving in water
The substance changes from liquid to solid at a low temperature
The reaction can be reversed to get back the original substance
Hint: gas bubbles are being produced. Chemical reaction or not?
yes
no
heat or light is produced
1. How is a chemical change different from a physical change?
there is no difference
a physical change creates a new substance
a chemical change creates a new substance
A student observes some sugar as it is heated and burns. The student concludes that a chemical reaction has occurred. Which of the following observations about the burning sugar provides evidence of a chemical reaction?
Heat is added to the sugar crystals.
The sugar melts and becomes a liquid.
Gas is produced as the sugar turns black.
No evidence of chemical reaction is present.
heat or light is produced
