8th Grade 2nd Semester Final Study Guide

A cork is able to float on water because it is ___

• equal in density to water

• a crystalline solid

• less dense than the water

• small in size

A manufacturer selected a metal to use in producing a lightweight button for clothing. A metal that has a density of 2.71 g/cm³ was selected. Which of the metals was selected?

• Metal 2

• Metal 4

• Metal 3

• Metal 1

Tags

NGSS.MS-PS1-2

The ability of a pond to freeze over in winter is a ___

• chemical property

• chemical change

• physical property

• physical change

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Each substance written to the right of the arrow in a chemical equation is a ___

• catalyst

• precipitate

• product

• reactant

A silver ring reacts with compounds containing sulfur in the air to form silver sulfide, a black substance that makes up the tarnish on the surface of silver objects. To remove the tarnish from the ring, students placed it in a pan lined with aluminum foil and added hot water. Baking soda was added to the hot water and stirred. Students made observations about the process. Which observation of this process provides evidence of a chemical reaction?

• The liquid solution changed color.

• Hot water heated the aluminum foil.

• The hot water cooled.

• The pan was lined with aluminum foil.

Tags

NGSS.MS-PS1-2

Which best explains why the total mass of the product(s) would be less than the total weight of the reactant(s) after a chemical reaction?

• Precipitates were created in the new solution.

• Atoms involved in the reaction lost mass.

• Gases were released to the atmosphere.

• A physical change occurred.

Tags

NGSS.MS-PS1-5

Which chemical equation is balanced?

• Na + O₂ → Na₂O

• 2Na + 2O₂ → 2Na₂O

• 4Na + O₂ → 2Na₂O

• 2Na₂ + O₂ → 2Na₂O

Tags

NGSS.MS-PS1-5

Students in a Science class made ball and stick models of the substances they were studying. The key shows the elements the students were working with. Which model represents an organic compound?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-1

According to the law of conservation of mass, how does the mass of the products in a chemical reaction compare to the mass of the reactants?

• There is no relationship.

• The masses are always equal.

• The mass of reactants is greater.

• The mass of products is sometimes greater.

Tags

NGSS.MS-PS1-5

Which of the following is NOT a possible sign of a physical change?

• a change in volume

• a change in appearance

• the release of energy

• a change in color