Formation of a New Substance

What is the difference between a chemical change and a physical change?

• A chemical change results in new substances, while a physical change does not.

• A chemical change is reversible, while a physical change is not.

• A chemical change occurs only in liquids, while a physical change occurs in solids.

• A chemical change involves a change in state, while a physical change does not.

What is an example of a physical change that does not create a new substance?

• Cutting paper into smaller pieces.

• Burning wood to ash.

• Mixing vinegar and baking soda.

• Dissolving sugar in water.

What is the significance of chemical changes in everyday life?

• They are involved in processes like cooking, rusting, and combustion, leading to new materials.

• They only occur in laboratories and have no impact on daily activities.

• They are responsible for physical changes in matter, such as melting and freezing.

• They are irrelevant to human activities and the environment.

What is a physical change?

• A change that affects one or more physical properties of a substance without altering its chemical composition.

• A change that alters the chemical composition of a substance.

• A change that occurs only at high temperatures.

• A change that affects the color of a substance without changing its state.

How can you tell if a chemical change has occurred?

• The substance changes state (solid, liquid, gas)

• There is a change in mass

• Look for signs like gas production, color change, temperature change, or formation of a solid.

• The substance becomes more reactive with water

What does it mean when bubbles and fizzing occur in a reaction?

• It indicates a chemical change, often the production of gas.

• It signifies a physical change without any new substances formed.

• It shows that the reaction is exothermic and releases heat.

• It means that the reactants are not mixing properly.

What is a chemical change?

• A process where one or more substances are transformed into new substances with different properties.

• A physical change that does not alter the chemical composition of a substance.

• A reaction that occurs only in the presence of heat or light.

• A process that involves the mixing of two or more substances without any change in their properties.

True or False: A physical change can result in an entirely different substance.

• True

• False

• Sometimes

• Only in certain conditions

What is an example of a physical change?

• Melting ice, where the ice changes from solid to liquid but remains water.

• Burning wood, which turns into ash and smoke.

• Rusting iron, which forms iron oxide.

• Cooking an egg, which changes its structure.

What is a precipitate?

• A gas that is released during a chemical reaction.

• A solid that forms and settles out of a liquid mixture during a chemical reaction.

• A liquid that evaporates when heated.

• A color change that occurs in a chemical reaction.