8th Grade 1st Semester Review

Front

What is a food web?

Back

A food web is a complex network of feeding relationships among organisms in an ecosystem, showing how energy and nutrients flow through different species.

Front

What happens to a food web if a key species is removed?

Back

Removing a key species can disrupt the balance of the food web, leading to population increases or decreases in other species.

Front

What is the law of conservation of mass?

Back

The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; the total mass of reactants equals the total mass of products.

Front

How do you calculate the mass of a product in a chemical reaction?

Back

To find the mass of a product, subtract the mass of the other products from the total mass of the reactants.

Front

What is acceleration?

Back

Acceleration is the rate of change of velocity of an object, indicating how quickly it speeds up or slows down.

Front

What are indicators of a chemical reaction?

Back

Indicators of a chemical reaction include the production of light or heat, formation of a gas, and formation of a precipitate.

Front

What is a precipitate?

Back

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

Front

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

Back

A physical change alters the form of a substance but not its chemical composition, while a chemical change results in the formation of new substances.

Front

What is the cell theory?

Back

The cell theory states that all living organisms are composed of cells, and all cells come from pre-existing cells.

Front

What is a reactant in a chemical reaction?

Back

A reactant is a substance that undergoes change during a chemical reaction.