District MOY Review - 8th Grade Science

Front

What word describes when water is attracted to other substances?

Back

Adhesion: The tendency of water molecules to be attracted to other substances, such as glass or soil.

Front

What does the principle of conservation of mass state in chemical reactions?

Back

Matter is not created or destroyed: In a chemical reaction, the total mass of the reactants equals the total mass of the products.

Front

Is change in color a physical change?

Back

False: Change in color often indicates a chemical change, not a physical change.

Front

How many TOTAL atoms are there in 3 MOLECULES of H2O?

Back

9: Each water molecule (H2O) contains 3 atoms (2 hydrogen and 1 oxygen), so 3 molecules contain 9 atoms.

Front

What characteristic is shown in the image?

Back

Polarity: Water molecules have a positive and a negative end, making them polar.

Front

What is cohesion in terms of water molecules?

Back

Cohesion: The attraction between water molecules, which allows them to stick together.

Front

What is capillary action?

Back

Capillary action: The ability of water to flow in narrow spaces without the assistance of external forces, due to adhesion and cohesion.

Front

What is the definition of a chemical reaction?

Back

Chemical reaction: A process that leads to the transformation of one set of chemical substances to another.

Front

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

Back

Physical change: A change that affects one or more physical properties of a substance without altering its chemical composition. Chemical change: A change that results in the formation of new chemical substances.

Front

What is the role of a catalyst in a chemical reaction?

Back

Catalyst: A substance that increases the rate of a chemical reaction without being consumed in the process.