Chemical Changes

Multiple Choice

What is the significance of understanding the difference between chemical and physical changes in our daily lives?

• It helps us cook food better

• It allows us to predict and control reactions

• It helps us understand the environment

• All of the above

Open Ended

What are some everyday examples where you have observed chemical changes taking place around you?

Open Ended

What always happens during a chemical change?

Multiple Choice

Which of the following words usually signify a chemical change?

• Burn, rot, rust, decompose, ferment, explode, corrode

• Melt, freeze, evaporate, condense

• Cut, break, crush, dissolve

• Mix, stir, blend, separate

Multiple Choice

A change where one or more new substances are created.

• Physical Change 
• Chemical Change 

Open Ended

Explain why the ability to rust is considered a chemical property of iron.

Multiple Select

Which of the following are examples of chemical properties?

• Ability to rust

• Ability to burn

• Ability to dissolve

• Ability to ferment

Multiple Choice

When charcoal is broken into smaller pieces, what type of change occurs and why?

• Physical change, because the substances remain the same

• Chemical change, because new substances are formed

• Physical change, because the color changes

• Chemical change, because energy is released

Multiple Choice

Which of the following best describes what happens when charcoal is broken into smaller pieces?

• It undergoes a chemical change.

• It undergoes a physical change.

• It turns into a new substance.

• It reacts with oxygen.

Open Ended

Explain the difference between a physical change and a chemical change using the example of charcoal.

Multiple Select

Which of the following statements are true about chemical reactions?

• One or more substances change into new substances.

• A substance present at the start is called a reactant.

• A substance produced in the reaction is a product.

• The composition of matter never changes.

Open Ended

What are the main reactants and the main product in the burning of charcoal?

Open Ended

What is always true of a chemical change that is never true of a physical change?

Open Ended

What are four possible clues that a chemical change has taken place?

Multiple Choice

Which of the following is NOT a possible clue that a chemical change has occurred?

• A transfer of energy

• A change in color

• A change in shape

• The production of a gas

Multiple Choice

Which of the following statements about energy transfer in chemical changes is correct?

• Energy is always absorbed during a chemical change.

• Energy is always released during a chemical change.

• Energy can be either absorbed or released during a chemical change.

• Energy transfer does not occur during a chemical change.

Multiple Select

Based on the information from the last two slides, which of the following are clues that a chemical change is occurring when cooking food?

• The food absorbs energy.

• The food changes color.

• The food changes shape.

• The food produces a gas.

Multiple Choice

What is a precipitate in the context of chemical changes?

• A gas that forms during a reaction

• A solid that forms and settles out of a liquid mixture

• A liquid that evaporates quickly

• A color change in a solution

Open Ended

Explain why the formation of bubbles when using some bathroom cleaners is considered a clue to a chemical change. What does this indicate about the reaction taking place?

Multiple Choice

What is the only way to be sure that a chemical change has occurred?

• Observing a color change

• Testing the composition of a sample before and after the change

• Seeing bubbles form

• Feeling a temperature change

Multiple Choice

When two antacid tablets are dropped into a glass of water and bubbles of carbon dioxide form, what does this demonstrate?

• A physical change

• A chemical change

• A change in state

• A reversible process

Multiple Select

Which of the following are clues that a chemical change may have occurred?

• Formation of a precipitate

• Production of a gas

• Change in temperature

• Melting of ice

Open Ended

After learning about chemical changes, what is one real-life example you can think of that involves a chemical change?

Open Ended

What happened to the match?