Chapter 1 - Chemistry and Measurement

Question 1

What is Chemistry?

Answer 1

the central science, everything depends on it

Question 2

Give some examples of what chemistry has provided for us in the world

Answer 2

• better crop yields
• more nutritious food
  -fuels
• better health (medications)

Question 3

What 3 phases does matter exist in?

Answer 3

Solid, liquid, gas

Question 4

What are pure substances?

Answer 4

they have a fixed composition and have unique properties that can be used to identify a substance
ex: elements and compounds

Question 5

What is a mixture?

Answer 5

composed of 2 or more pure substances in which each substance maintains its identity and they can be separated into their components

Question 6

What is a homogenous mixture?

Answer 6

“solution” in which the composition is the same throughout
- if you split it into two bottles/pieces, the two pieces/bottles would have the same components

Question 7

What is a solution

Answer 7

a solute dissolved into a solvent

Question 8

What is the solute?

Answer 8

the substance being dissolved
ex: salt or sugar

Question 9

What is the solvent?

Answer 9

the dissolving medium
ex: water (H20)

Question 10

Give an example of a homogenous mixture

Answer 10

coffee, metal alloys (Brass, Bronze)

Question 11

What is a heterogenous mixture?

Answer 11

mixture that is non uniform in appearance in which its composition varies throughout
ex: a rock, choc chip cookie, salad

Question 12

What is filtration as a method of separating mixtures?

Answer 12

passing a mixture through fine pores to separate solid from a liquid

Question 13

What is distillation as a method of separating mixtures?

Answer 13

separation of homogenous mixtures by boiling points (heat it up until one substance’s boiling point is hit)

Question 14

What is chromatography as a method of separating mixtures?

Answer 14

separating a mixture by color (paper chromatography)

Question 15

What are extensive properties?

Answer 15

dependent on the amount of the substance and cannot be used to identify a substance
ex: mass, volume

Question 16

What are intensive properties?

Answer 16

independent of the amount of the substance and can be used to identify a substance
ex: boiling point, specific heat, density

Question 17

What are physical properties?

Answer 17

properties than can be measured w/o changing the identity of the substance
ex: color, boiling point

Question 18

What is density?

Answer 18

mass/volume, an intensive property made up of 2 extensive properties
ex: the difference between cake and cheesecake

Question 19

What is solubility?

Answer 19

how much of a substance will dissolve in a specific amount of solvent at a specific temp
ex: KNO3 -> 32g/100g H20 @ 20 degrees C

Question 20

Absorbance and Transmittance

Answer 20

a substance has a specific color due to its absorbance and transmittance of light
- the color is what is transmitted because it was not absorbed

Question 21

What are chemical properties?

Answer 21

properties that can be determined only by changing the identity and composition of the substance
- destructive test is needed
ex: Flammability

Question 22

nano- (n)

Answer 22

10^-9

Question 23

pico- (p)

Answer 23

10^-12

Question 24

What are the 2 things that accuracy is dependent upon?

Answer 24

1. The measuring device
2. The skill of the operator

Question 25

What do significant figures express?

Answer 25

the degree of uncertainty (the margin of error)

Question 26

Sig Fig Addition and Subtraction Rule

Answer 26

the answer cannot be more accurate than the least accurate number in the calculation
- no more decimal points than the number with the leat amount of decimal points

Question 27

Sig Fig: 8.947 + 3.9 = ?

Answer 27

12.847 -> correct sig figs: 12.8
(ONLY 1 DECIMAL POINT)

Question 28

Sig Fig Multiplication and Division Rule

Answer 28

the answer must follow the number in the problem with the least number of sig figs

Question 29

Sig Fig: 42.8 x 1.1 = ?

Answer 29

47.08 -> correct sig figs: 47
(ONLY 2 SIG FIGS)

Question 30

Sig Figs: If you divide 24.897 L of beer equally into 20 bottles, how much would be in each bottle?

Answer 30

24.897/20 = 1.24485 -> correct sig figs: 1.2449
- There are exactly 20 bottles (counted), exact numbers are assumed to have infinite sig figs
- so you follow the number of sig figs in: 24.897

Question 31

milli- (m)

Answer 31

10^-3

Question 32

micro- (µ)

Answer 32

10^-6

Question 33

mega- (M)

Answer 33

10^6

Question 34

kilo- (k)

Answer 34

10^3

Question 35

centi- (c)

Answer 35

10^-2

Question 36

deci- (d)

Answer 36

10^-1