Physical & Chemical Reactions

What happens during oxidation?

• A substance combines with oxygen, often resulting in rusting of metals.

• A substance loses electrons and gains protons.

• A substance gains electrons and loses protons.

• A substance is completely destroyed by heat.

What is an example of a chemical change in cooking?

• Baking a cake is a chemical change because the ingredients undergo a chemical reaction to form a new product.

• Boiling water is a chemical change because it transforms into steam.

• Frying an egg is a physical change because the egg remains the same substance.

• Mixing sugar and water is a chemical change because it creates a new solution.

What is combustion?

• A process where a substance reacts slowly with oxygen, producing heat and light.

• A chemical change that occurs when a substance reacts rapidly with oxygen, producing heat and light.

• A physical change that occurs when a substance is heated without oxygen.

• A reaction that occurs only in the absence of oxygen, producing smoke.

Can a physical change be reversed?

• Yes, many physical changes can be reversed, such as freezing and melting water.

• No, physical changes are always permanent.

• Yes, but only in certain conditions.

• No, once a physical change occurs, it cannot be undone.

Is breaking a vase a physical or chemical change?

• A physical change because the material remains the same, just in smaller pieces.

• A chemical change because it alters the chemical composition of the vase.

• A physical change because it creates a new substance.

• A chemical change because it involves a reaction with air.

Example of a physical change:

• A snowman melting is a physical change because it changes state from solid to liquid but remains water.

• Burning wood to ash is a physical change.

• Dissolving sugar in water is a chemical change.

• Freezing water into ice is a physical change.

What is an example of a chemical change in digestion?

• Food is broken down into new substances that the body can use.

• Food is chewed into smaller pieces.

• Food is absorbed into the bloodstream.

• Food is stored in the stomach for later use.

What is rusting?

• A process where iron is coated with paint to prevent corrosion.

• A chemical change that occurs when iron reacts with oxygen and moisture, forming iron oxide.

• A method of recycling metals by melting them down.

• A physical change that occurs when iron is exposed to sunlight.

Example of a chemical change:

• Fireworks going off is a chemical change because it produces new substances and energy.

• Melting ice is a chemical change because it transforms from solid to liquid.

• Dissolving sugar in water is a chemical change because it creates a new substance.

• Rust forming on iron is a chemical change because it involves a physical change.

What is an example of a physical change in hair?

• Dyeing hair a different color

• Getting a haircut

• Perming hair to create curls

• Using hair gel to style hair