Alchemy Quiz 05

How many elements are in NaHCO₃?

• 3

• 4

• 6

• 12

Answer explanation

To find the number of elements in a compound, you count the number of chemical symbols (capital letters).

Tags

NGSS.MS-PS1-1

If a copper compound is in solution, how would we designate that after the compound formula?

• (s)

• (l)

• (g)

• (aq)

Answer explanation

(s) = solid; (l) = liquid; (g) = gas; (aq) = aqueous - substance is dissolved in water.

Which of the following is false about atoms, elements and compounds?

• Different kinds of atoms can combine to make one kind of element.

• Compounds are made of more than one kind of element.

• Elements and compounds are both made of atoms.

• An element is always made of only one kind of atom.

Answer explanation

An element is made up of only one kind of atom.

Tags

NGSS.MS-PS1-1

Which statement is NOT a description of a chemical reaction?

• A liquid is heated on a Bunsen burner and its temperature rises.

• A solid is dropped into a beaker of liquid and an explosion occurs.

• Two liquids are mixed in a beaker and a solid forms at the bottom of the beaker.

• A solid is dropped into a beaker of liquid and a gas is released.

Answer explanation

Increasing the temperature of a substance is a physical change.

Tags

NGSS.MS-PS1-2

The copper cycle is a demonstration of what principle of chemistry?

• Most elements are metallic solids.

• Metals are excellent conductors.

• Elements exist as gases, liquids, or solids.

• Mass is conserved in chemical reactions.

Answer explanation

In the copper cycle, despite a series of chemical transformations, the final mass of copper should be equal to the initial mass. This demonstrates that the copper atoms were only rearranged, not created or destroyed.

Tags

NGSS.MS-PS1-5

Which of the following is evidence of a chemical change?

• change in shape

• change in size

• change in odor

• change in state or phase

Answer explanation

Examples of chemical changes include burning (wood, paper, or fuel), rusting (of iron), cooking (eggs, or baking a cake), and digestion (of food). These are all processes where a new substance is formed with different properties, unlike a physical change where the substance remains the same.

Tags

NGSS.MS-PS1-2

Which of the following statements about chemical changes is false?

• Chemical changes can be reversed by physical changes.

• Chemical changes form new substances that have different properties.

• Chemical changes can be detected.

• Compounds can be broken down through chemical changes.

Answer explanation

Chemical changes are detectable, form new substances, and can break down compounds into similar substances. You need to select the statement that is false.

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

Which of the following statements about physical changes is false?

• Dissolving is a physical change.

• Changes of state (e.g., melting, boiling, etc.) are physical changes.

• Physical changes are often easily reversible.

• Physical changes can produce new substances.

Answer explanation

Physical changes do not produce new substances.

Tags

NGSS.MS-PS1-4

In the following chemical equation, which are the reactants? Check all that apply. 

Fe_(s) + CuSO_4(aq) --> FeSO_4(aq) + Cu_(s)

• Fe_(s)

• CuSO_4(aq)

• FeSO_4(aq)

• Cu_(s)

Answer explanation

Reactants are on the left side of a chemical equation.

Tags

NGSS.MS-PS1-2

In the following chemical equation, which are the products? Check all that apply.

Fe_(s) + CuSO_4(aq) --> FeSO_4(aq) + Cu_(s)

• Fe_(s)

• CuSO_4(aq)

• FeSO_4(aq)

• Cu_(s)

Answer explanation

Products are on the right side of a chemical equation.

Tags

NGSS.MS-PS1-2