(DONE) Chapter 2 - Lecture 2

Question 1

chemistry

Answer 1

study of matter and its composition, structure, properties, and reactions

Question 2

Explain the scientific method

Answer 2

• method for acquiring scientific knowledge
• observation, hypothesis, experiment, back to observation (cyclical until theory/law achieved)
• theory/model, prediction, experiment, back to theory (modified as needed)

Question 3

• observation
• law
• theory

Answer 3

• observation: possible explanation for observations
• law: summary of observed behaviour
• theory: explanation of the observed behaviour

Question 4

alkali metals (4)

Answer 4

• 1st group on the periodic table
• combust in water
• shiny
• soft

Question 5

groups

Answer 5

vertical rows on periodic table

Question 6

periods

Answer 6

horizontal rows on periodic table

Question 7

alkaline earth metals (4)

Answer 7

• second group
• shiny
• soft
• moderately reactive with water

Question 8

transition metals (1)

Answer 8

• group 4-12

Question 9

metalloids (1)

Answer 9

• staircase (B, Si, Ge, As, Sb, Te, Po)

Question 10

halogens (3)

Answer 10

• group 17
• react vigorously
• gases at close to room temperature

Question 11

noble gases (3)

Answer 11

• group 18
• stable
• little to know tendency to form compounds

Question 12

lanthanoids

Answer 12

• period 6 (topmost bottom of table)

Question 13

actinoids

Answer 13

• period 7 (bottom most bottom of table)

Question 14

exact numbers

Answer 14

• counted/ defined numbers with no uncertainty and therefore infinite sig figs
• pi, e, etc

Question 15

measured numbers

Answer 15

• obtained with a measuring device, will always have uncertainty

Question 16

precision

Answer 16

• how close multiple measurements are to eachother

Question 17

accuracy

Answer 17

• how close a measurement is to the true or accepted value

Question 18

random errors (2)

Answer 18

• Due to uncontrolled variables

- Result in a decrease in precision

Question 19

systematic errors (2)

Answer 19

• Constant

- Lead to decrease in accuracy but without impact on precision

Question 20

Significant figure rules (5)

Answer 20

1. All non zero integers count as sig figs
2. Leading zeroes do not count (ex: 0.1, .002; both have 1 sig fig)
3. Trailing zeros count if the number contains a decimal
4. Captive zeros always count
5. Exact numbers (counted or defined or converted) have unlimited number of significant figures.

Question 21

Standard deviation rule of 20

Answer 21

• the standard deviation must have the same number of sig figs as the mean

Question 22

addition and subtraction sig fig rule

Answer 22

• Number of sig figs in the answer will be limited by the term with the least number of decimal places
• 1.634 + .12 = 1.754 but can only be rounded to 1.75 because 2 decimal places

Question 23

Multiplication and division

Answer 23

• use the least number of sig figs