MEASUREMENT: Ch. 2 Using Measurements I Units of Measurement II Unit Conversions III Honors Chem 1
MEASUREMENT: Ch. 2 Units of Measurement (p.33 - 39)
A. Number vs. Quantity Measurements represent quantitiesQuantity is a number + unit UNITS MATTER!!
B. SI Units • scientists use one common measurement system • Le Systéme International d’Unités, or SI • Allows scientists to compare their research findings all over the world!
B. SI Units Quantity Symbol Base Unit Abbrev. Length l meter m Mass m gram g Time t second s Temp T kelvin K Amount n mole mol
B. SI Units K H D b d c m _ _ _ _ n _ _ p kilo deci nano pico centi micro milli base unit
Board & Buddy • Shoulder partner • One person grab a white board & marker • Write which unit would be best for the following situations- talk it out!
Which unit would be best? distance between Nashville and Orlando
Which unit would be best? animal track size
Which unit would be best? how long to complete the Nashville Rock n Roll Marathon (26.2 miles)
Which unit would be best? size of a paper clip
Which unit would be best? how far from street to the top of Big Ben
Which unit would be best? amount in a jug of milk
Which unit would be best? thickness of a piece of hair
Which unit would be best? thickness of a single piece of newspaper
Which unit would be best? teaspoon of salt
Which unit would be best? distance to the moon
m V D = C. Derived Units • combination of base units • volume (m3 or cm3) length length length 1 cm3 = 1 mL 1 dm3 = 1 L • density (g/mL or g/cm3)mass per volume
D. Density directly proportional! Mass (g) Volume (cm3)
m m m m D D D D V V V V D. Density D = m V m = DV V = m D
Example #1 • An object has a volume of 825 cm3 and a density of 13.6 g/cm3. Find its mass. m = DV m = (13.6 g/cm3)(825cm3) m = 11,200 g m = 1.12 x 104 g
WORK: V = m D V = 25 g 0.87 g/mL Example #2 • A liquid has a density of 0.87 g/mL. What volume is occupied by 25 g of the liquid? V = 29 mL
E. Converting temperatures • Celcius (°C) • Kelvin (K) • Fahrenheit (°F) K = °C + 273 °C = K - 273