3/8 DONOW 8.5E Chemical Reactions

Which of the following could indicate a chemical change? 

• All of the answers could indicate Chemical Change 

• a color change has occurred 

• bubbles appear 

• properties are different after a reaction

A copper penny turning greenish after a few years is an example of...

• Chemical Change

• Physical Change

Which of the following is NOT an example of a physical change?

• crumpled paper

• pencil sharpening

• shrunken clothing

• sour milk

Which of the following IS a SIGN of a chemical reaction?

• Dissolving

• Melting

• Bubbles form

• Expected color change

Which one is NOT a sign that a chemical reaction has occurred?

• precipitate

• energy change

• unexpected color change

• dissolving

A group of students investigated physical and chemical changes using paper.  The students recorded their observations in a table.
Which student correctly recorded all the changes that took place?

• Student 1

• Student 2

• Student 3

• Student 4

For an investigation a student poured a blue solution of CuSO₄ into a beaker. The student placed a shiny, silver-colored strip of zinc metal in the solution and observed the changes.
The student inferred that a chemical reaction occurred. What evidence supports this inference?

• A dark solid formed on the zinc metal.

• 
  The zinc metal remained silver-colored and shiny

• The CuSO₄ solution turned blue when the zinc metal was added.

• None of these

Four students performed four different investigations by combining different substances. Their results are shown in the table provided. In which experiment are new substances being formed?

• Experiment 1

• Experiment 2

• Experiment 3

• Experiment 4