Question 1

Which of the following best describes why you must wear safety glasses with side shields and a lab coat in the chemistry laboratory?

Accepted Answer

To protect your eyes and body from chemical splashes and broken glass.

Question 2

Which of the following is an example of a homogeneous mixture?

Accepted Answer

Sweetened iced tea

Question 3

A student wants to separate a mixture of sand and salt dissolved in water. Which sequence of separation techniques should they use?

Accepted Answer

Filtration followed by distillation

Question 4

Which of the following statements about compounds is TRUE?

Accepted Answer

Compounds have a definite composition according to the Law of Constant Composition.

Question 5

Which of the following is a chemical property?

Accepted Answer

Flammability

Question 6

Which process is a physical change?

Accepted Answer

Melting of ice

Question 7

Which of the following best describes the Law of Conservation of Energy?

Accepted Answer

Energy is neither created nor destroyed in a physical or chemical change.

Question 8

A sample of matter is uniform throughout and can be separated into two substances by a physical process. How should this sample be classified?

Accepted Answer

Homogeneous mixture

Question 9

Which of the following is an example of potential energy?

Accepted Answer

Energy stored in a battery

Question 10

Which of the following best explains why water can exist as a solid, liquid, or gas?

Accepted Answer

The arrangement and movement of water molecules change with temperature.

Question 11

Which of the following is NOT a major field of chemistry?

Accepted Answer

Astronomical chemistry

Question 12

Which separation technique would be most appropriate to separate the components of ink in a marker?

Accepted Answer

Chromatography

Question 13

Which of the following is a pure substance?

Accepted Answer

Oxygen gas (O$$_2)$$

Question 14

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

Accepted Answer

An element contains only one kind of atom, while a compound contains two or more kinds of atoms chemically combined.

Question 15

A student observes that a metal coin turns green after being left outside in the rain. This is an example of:

Accepted Answer

A chemical change

Question 16

Which of the following is the best example of a heterogeneous mixture?

Accepted Answer

Chocolate chip cookie

Question 17

Which of the following best describes the energy associated with the motion of atoms or molecules?

Accepted Answer

Kinetic energy

Question 18

Which of the following is a correct chemical symbol for an element?

Accepted Answer

Fe

Question 19

A sample of electrum is analyzed and found to contain both gold and silver atoms mixed uniformly. How should electrum be classified?

Accepted Answer

Homogeneous mixture (alloy)

Question 20

Which of the following best describes why chemistry is called the 'central science'?

Accepted Answer

It connects and underpins concepts in biology, physics, medicine, and many other sciences.

Introduction to Chemistry: Matter, Classification, and Laboratory Foundations

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