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WorksheetsSigns of Chemical Reactions
Total questions: 11
Worksheet time: 11mins
A change in the shape of an object is an example of _________________.
a chemical change
energy
an endothermic change
a physical change
Rohan, Mason, and Samuel are having the time of their lives in their science class, witnessing a fascinating chemical reaction. They are on the edge of their seats, eager to determine if a chemical reaction has truly taken place. They understand that a chemical reaction has occurred if:
a new solid, known as a precipitate, is formed.
there is a noticeable change in color.
there is a shift in temperature.
All of these answers are valid indicators of a chemical reaction.
You have 2 chemicals, CHEMICAL A and CHEMICAL B. They are both liquids. When you combine them you notice some crystals starting to form within them. Did a chemical reaction occur?
Yes
No
Which example is a chemical change?
baking powder fizzing
ice melting
water boiling
sugar cube dissolving
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
When vinegar and baking soda are combined, bubbles and foam are produced.
What evidence demonstrates that a chemical change has occurred?
A color change occurs.
A gas is formed.
A solid is dissolved.
A precipitate is formed.
Which scientific observation, shown in the chart, indicates that a chemical reaction has NOT occurred?
Number 1
Number 2
Number 3
Number 4
What is a chemical reaction?
a change in matter when the molecules rearrange to make new molecules
a change in matter when matter changes its form or appearance
a change in matter when the physical appearance changes
a very boring change in matter
Ethan, Luna, and Harper were having a science experiment party! They noticed several interesting things happening during their experiments. Which of the following observations would NOT indicate that a chemical reaction has occurred?
Ethan noticed a change in temperature in one of his experiments
Luna saw the formation of a precipitate in her test tube
Harper observed the emission of light from one of her mixtures
They mixed two substances together, but nothing else seemed to change
