Unit 2 Test Review: Conservation in Matter

The periodic table is organized into three main categories. Which of the following correctly identifies these categories?

• solids, liquids, and gases

• metals, nonmetals, and metalloids

• elements, compounds, and mixtures

• natural, synthetic, and alloys

What does the subscript '3' in the chemical formula Al₂O₃ indicate?

• There are 3 aluminum atoms in the molecule.

• There are 3 oxygen atoms in the molecule.

• There are 3 molecules of aluminum oxide.

• There are 3 atoms of both aluminum and oxygen in the molecule.

Tags

NGSS.MS-PS1-1

Which of the following best describes the formula CaCO₃?

• 1 calcium, 1 carbon, 3 oxygen

• 1 calcium, 3 carbon, 3 oxygen

• 3 calcium, 1 carbon, 1 oxygen

• 3 calcium, 3 carbon, 1 oxygen

Tags

NGSS.MS-PS1-1

In the chemical formula for magnesium hydroxide, Mg(OH)₂, what does the subscript '2' outside the parentheses indicate?

• There are 2 magnesium atoms in the molecule.

• There are 2 oxygen atoms and 2 hydrogen atoms in the molecule.

• There are 2 molecules of magnesium hydroxide.

• There are 2 magnesium atoms, 2 hydrogen atoms and 2 oxygen atoms in the molecule.

Tags

NGSS.MS-PS1-1

Which of the following statements correctly describe how to identify the number of atoms in a chemical formula? Select ALL that apply.

• If there is no subscript number after an element symbol, it means there is only one atom of that element.

• A coefficient before a chemical formula multiplies the number of each type of atom in the formula by that coefficient.

• Parentheses in a chemical formula are used to group elements, and the subscript outside the parentheses multiplies the number of atoms of each element inside the parentheses.

• The element with the highest subscript number is the most abundant in the compound.

• The subscript number following an element symbol indicates the number of atoms of that element in the molecule.

Which property does NOT normally describe metals?

• brittle

• good conductors of electricity

• malleable and ductile

• shiny luster

Which group of elements is brittle, shiny, and described as semiconductors?

• metals

• nonmetals

• metalloids

• transition metals

You need to find a material to make an electrical wire. What do you choose and why?

• A nonmetal because it is a good insulator.

• A metal because it is ductile.

• A metal because it is shiny.

• A metalloid because it is brittle.

During a laboratory experiment, a student mixed two colorless and odorless solutions. The only observable change was a strange odor, the solution was still colorless, there was no change in temperature, but a white solid formed. What can be concluded about the nature of this reaction?

• It is a physical change because no color change was observed.

• It is a chemical change because heat was absorbed, and the temperature changed.

• It is a physical change because the composition of the solution did not change.

• It is a chemical change because a new substance was formed.

Tags

NGSS.MS-PS1-2

Bubbles form when two or more substances are combined ...

• Chemical Change
• Physical Change

Tags

NGSS.MS-PS1-2