8th grade final exam short

What is a chemical equation?

• A shorthand method to describe a chemical reaction using chemical formulas and other symbols.

• A number used to represent the number of units of each substance.

• A reaction that releases heat.

• A solid that forms when two liquids react.

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

Which type of reaction involves two or more elements or compounds combining to make a more complex substance?

• Synthesis reaction

• Decomposition reaction

• Single replacement reaction

• Double replacement reaction

What happens in a double replacement reaction?

• Two elements in different compounds trade places to form two new substances.

• One element replaces another element in a compound.

• Two or more elements or compounds combine to make a more complex substance.

• A chemical reaction absorbs heat.

Tags

NGSS.MS-PS1-5

What is the difference between coefficients and subscripts in chemical reactions?

• Coefficients can be changed to balance equations, subscripts cannot.

• Subscripts can be changed to balance equations, coefficients cannot.

• Both coefficients and subscripts can be changed to balance equations.

• Neither coefficients nor subscripts can be changed to balance equations.

What is an inhibitor?

• A substance that slows down a chemical reaction or prevents it from occurring by combining with a reactant.

• A substance that speeds up a chemical reaction.

• A type of natural resource.

• A repeating unit that makes up a polymer.

Tags

NGSS.HS-PS1-5

Which of the following best defines a synthetic material?

• A chemical or resource made by humans.

• A naturally occurring resource.

• A type of natural fiber.

• A repeating unit in a polymer.

Tags

NGSS.MS-PS1-3

Which of the following is a natural fiber?

• Cotton

• Nylon

• Polyester

• Acrylic

Tags

NGSS.MS-PS1-3

What is a monomer?

• The repeating unit that makes up a polymer.

• A type of synthetic fiber.

• A natural resource.

• A chemical that prevents reactions.

Why can polymers be strong, flexible, and elastic?

• Due to the structure of long molecule chains.

• Because they are made from natural resources.

• Because they are always synthetic.

• Because they are made from monomers only.

What are synthetic chemicals used for in medicines?

• To make food taste better

• To treat or cure disease

• To power vehicles

• To create new colors