Introduction to Chemical Reactions Answers

Which of these most likely represents a chemical change?

Reggie and Charlotte are baking oatmeal cookies. They dip the baked cookies in melted chocolate. The chocolate cools to form a hardened coating. Reggie argues the entire chocolate-covered cookie has undergone a chemical change. Charlotte disagrees, saying only the original oatmeal cookie has undergone a chemical change, not the chocolate coating.

Cherylanne mixes together Chemical A and Chemical B in a test tube, forming Chemical C. The mixture instantly turns cool to the touch. She then adds Chemical D, and the reaction becomes hot and explodes.

When baking soda and vinegar react, the surface bubbles. What does this most likely indicate?

Pedro wants to create a chemical reaction between oil and water. He adds oil to a beaker of water and notices that the liquids do not mix. He then shakes the beaker and the drops of oil become suspended through the water for a few moments before returning to their separate layers.

Which is an example of a chemical reaction?

Two chemicals react in an endothermic reaction. What can be known about this reaction?

Which is evidence that a chemical reaction has likely occurred?

Which best describes what happens to the atoms in a chemical reaction?

For a science project, Janet performs four experiments that are supposed to show a chemical reaction. She displays her results in a table.