Lecture 1

Question 1

7 Common SI units

Answer 1

Mass (kg)
Length (m)
Time (s)
Temperature (K)
Amount of Substance (mol)
Electric Current (A)
Luminous Intensity (Candela -cd)

Question 2

Decimal prefix mega

Answer 2

1,000,000 g

Question 3

Decimal prefix kilo

Answer 3

1,000 g

Question 4

Decimal prefix deci

Answer 4

0.1m

Question 5

Decimal prefix centi

Answer 5

0.01m

Question 6

Decimal prefix milli

Answer 6

0.001 m

Question 7

Decimal prefix micro

Answer 7

0.000001 m

Question 8

Decimal prefix nano

Answer 8

0.000000001 m

Question 9

Decimal prefix pico

Answer 9

0.000000000001m

Question 10

Significant figure rules

Answer 10

1. Non-zero digits are always significant
2. Leading zeros are never significant
3. Trailing zeros are significant if a decimal
4. Zeros between nonzero digits are always significant

Question 11

What is the point of significant figures?

Answer 11

Indicate the degree of (un)certainty of a measurement - the greater number of SF, the greater the certainty

Question 12

How many significant figures when multiplying or dividing?

Answer 12

Same number of SF as measurement w/ fewest number of SF

Question 13

How many significant figures when adding or substracting?

Answer 13

Same number of decimal places as measurements with fewest decimal places

Question 14

Law of Mass Conservation

Answer 14

1. Atoms cannot be created or destroyed
2. In chemical reactions, atoms of one element cannot be converted in atoms of another element
3. Mass of reactants = mass of products

Question 15

Ionic Compounds

Answer 15

• NaCl
• often metal and non-metal
• crystalline solids (made of ions)
• high melting and boiling points
• conduct electricity when melted or dissolved in water
• many soluble in water but not in no polar solvents

Question 16

Covalent Compounds

Answer 16

• O2, CO2, Cellulose
• often non-metal + non-metal
• gases, liquids, or solids (made of molecules)
• low melting and boiling points
• poor electrical conductors in all phases
• many solubles in no polar solvent but non in water

Question 17

Density

Answer 17

Mass/volume (g/mL, g/cm3, g/L, kg/L, and even kg/m3)

Question 18

Speed/velocity

Answer 18

Distance/time

Question 19

Concentration

Answer 19

Number/volume