Chemical Properties and Reactions

The video tutorial covers key chemistry concepts, including definitions of molecules, pure substances, compounds, and mixtures. It explains physical and chemical properties, and how to identify chemical reactions through signs like gas production, light emission, temperature change, and color change. The tutorial also explores the science behind glow sticks and chemiluminescence.

What is a molecule?

• A single atom

• Two or more atoms chemically bonded

• A mixture of different substances

• A type of chemical reaction

Which of the following is a pure substance?

• Salt water

• Air

• Pure water

• Sand

How does a compound differ from its constituent elements?

• It is a single element

• It has different properties from its elements

• It is a physical mixture of elements

• It has the same properties as its elements

What is a mixture?

• A single pure substance

• A physical combination of substances

• A chemical bond between elements

• A type of chemical reaction

Which of the following is a physical property?

• Flammability

• Color

• Reactivity

• Rusting

What indicates a chemical property?

• The substance's taste

• The substance's color

• The substance's state of matter

• The substance's reactivity

What is a sign that a chemical reaction has occurred?

• The substance dissolves in water

• The substance changes temperature

• The substance changes shape

• A new substance with new properties forms

What happens when baking soda and vinegar are mixed?

• They become a single compound

• They produce carbon dioxide gas

• They form a solid

• They change color

What process powers glow sticks?

• Combustion

• Photosynthesis

• Evaporation

• Chemiluminescence

What is a precipitate?

• A color change in a substance

• A solid formed from a solution

• A gas formed from a reaction

• A liquid formed from a gas