Question 1

Which of the following best describes an alloy such as brass?

Accepted Answer

A homogeneous mixture of metals

Question 2

A student is given a sample of 14K gold jewelry. Which statement about this sample is correct?

Accepted Answer

It is a mixture because it contains gold and other metals physically combined.

Question 3

Which of the following is an example of a chemical change?

Accepted Answer

Burning a piece of wood in a campfire

Question 4

A sample of a substance has a mass of 50.0 g and occupies a volume of 20.0 cm³. What is its density?

Accepted Answer

2.5 g/cm³

Question 5

Which property is intensive and can be used to help identify a substance regardless of sample size?

Accepted Answer

Density

Question 6

Which separation technique would be most effective for separating a mixture of sand and iron filings?

Accepted Answer

Using a magnet

Question 7

Which of the following statements about the states of matter is correct?

Accepted Answer

Liquids have a definite volume but no definite shape.

Question 8

Which process is an example of an endothermic change?

Accepted Answer

Ice melting in a drink

Question 9

A chemist has 3.00 moles of sodium (Na). How many atoms of sodium does this represent? (Avogadro's number = 6.02 × 10²³)

Accepted Answer

1.81 × 10²⁴ atoms

Question 10

Which of the following best describes the difference between a compound and a mixture?

Accepted Answer

A compound has elements chemically bonded, while a mixture has substances physically combined.

Question 11

Which of the following is a diatomic element in its natural state?

Accepted Answer

O₂

Question 12

A 10.0 g sample of a metal is placed in a graduated cylinder containing 20.0 mL of water. The water level rises to 23.0 mL. What is the density of the metal?

Accepted Answer

3.33 g/mL

Question 13

Which of the following is an example of an allotrope?

Accepted Answer

Ozone (O₃) and oxygen gas (O₂)

Question 14

Which of the following is a physical property?

Accepted Answer

Melting point

Question 15

A sample of neon contains 2.65 × 10²³ atoms. (Molar mass of Ne = 20.18 g/mol) What is the mass of this sample?

Accepted Answer

8.87 g

Question 16

Which of the following best illustrates the law of conservation of energy in a chemical reaction?

Accepted Answer

The total energy before and after a reaction remains constant, though it may change forms.

Question 17

Which of the following is a heterogeneous mixture?

Accepted Answer

Muddy water

Question 18

Which change of state is described as deposition?

Accepted Answer

Gas to solid

Question 19

A sample of uranium has a mass of 5.69 moles. (Molar mass of U = 238.0 g/mol) What is the mass of the sample?

Accepted Answer

1,353 g

Question 20

Which of the following is NOT a method for separating a homogeneous mixture?

Accepted Answer

Filtration

Foundations of Matter: Classification, Properties, and Measurement in General Chemistry

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