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