CFA 1.3 B -Understanding Endothermic Reactions

Which of the following is an example of an endothermic reaction from Maria's experiments?

• Burning a piece of paper

• Melting ice cubes

• Mixing salt in water

• Freezing water

What is the main characteristic of an endothermic reaction?

• It releases heat to the surroundings.

• It absorbs heat from the surroundings.

• It produces light.

• It forms a solid from a liquid.

Which observation best indicates that the reaction between baking soda and vinegar is endothermic?

• The mixture produces bubbles.

• The bowl feels warmer.

• The bowl feels cooler.

• The mixture changes color.

Maria wants to determine if a reaction is endothermic or exothermic. She plans to measure the temperature of the surroundings before and after the reaction. Which reasoning best supports her plan?

• If the temperature increases, the reaction is endothermic.

• If the temperature decreases, the reaction is exothermic.

• If the temperature decreases, the reaction is endothermic.

• If the temperature stays the same, the reaction is endothermic.

Suppose Maria wants to design an experiment to compare the energy changes in melting ice and burning paper. Which approach would best help her analyze the difference between these two processes?

• Measure the mass of the substances before and after the reactions.

• Observe the color changes during the reactions.

• Measure the temperature change of the surroundings for each process.

• Count the number of bubbles produced in each reaction.