Chapter 1

Question 1

What is an extensive property?

Answer 1

a property that depends on the quantity of the sample (ex. mass)

Question 2

What is an intensive property?

Answer 2

a property that remains unchanged regardless of sample size (ex. boiling point)

Question 3

What is a physical property?

Answer 3

a property that substances display without changing their compositions (ex, odor, taste, color, melting point, density, etc.)

Question 4

What is a chemical property?

Answer 4

a property that substances display only by changing composition via chemical change (ex. corrosiveness, flammability, acidity, toxicity)

Question 5

What are pure substances?

Answer 5

substances that are composed of only a single type of atom or molecule

Question 6

What is an element?

Answer 6

substances that cannot be chemically broken down into simpler substances

Question 7

What is a compound?

Answer 7

a substance composed of two or more elements in fixed, definite proportions

Question 8

What is a mixture?

Answer 8

a substance composed of two or more different types of atoms or molecules that can be combined in variable proportions

Question 9

What is a heterogeneous mixture?

Answer 9

a mixture whose compositions vary from region to region

Question 10

What is a homogenous mixture?

Answer 10

a mixture whose composition remains the same throughout

Question 11

What is a hypothesis?

Answer 11

a tentative interpretation or explanation of observations

Question 12

What is an experiemnt?

Answer 12

highly controlled procedures designed to generte observations that can support or refute a hypothesis

Question 13

What is a scientific theory?

Answer 13

a model for the way nature is that attempts to explain why nature is that way (ex. Dalton’s atomic theory proposed that matter is composed of small indestructible particles (atoms) that rearrange during chemical changes such that the total amount of mass remains constant)

Question 14

What is a scientific law?

Answer 14

a brief statement that summarizes past observations and predict future ones (ex. law of conservation of mass states, “In a chemical reaction, matter is neither created nor destroyed”)

Question 15

What are derived units?

Answer 15

combinations of other units

Question 16

What is accuracy?

Answer 16

how close the measured value is to the actual value

Question 17

What is precision?

Answer 17

how close a series of measurements are to one another or how reproduceable they are

Question 18

What are significant figures?

Answer 18

the non-place-holding digits (those not simply marking the decimal place)

Question 19

How do you determine significant figures?

Answer 19

1. All nonzero digits are significant
2. Zeroes between two figures are themselves significant
3. Zeroes at the beginning of a number are never significant
4. Zeroes at the end of a number are significant and after the decimal point are always significant
5. Zeroes at the end of a number and before the decimal point are not significant if a decimal point is not present