A.P. Ch. 1 Review Work Chemical Foundations

Lab Equipment Graduated Cylinder: used for accurately measuring liquid volumes Beaker: used for stirring, mixing, and heating liquids with a spout to aid in pouring Burette: used in titrations to dispense specific volumes of titrating solution Volumetric Flask: used for making dilutions at a specific volume

Lab Equipment Continued… Erlenmeyer Flask: used for swirling solutions and for storage Bunsen Burner: used for heating substances Crucible: ceramic bowl used to heat substances to high temperatures Pipette: used for dispensing precise amounts of liquid

SI Units Internationally recognized units of measure to standardize scientific community Mass – Kilogram (kg) Length – Meter (m) Time – Seconds (s) Temperature – Kelvin (K) or Celsius (ºC) Prefixes: Giga (billion), Mega (million), Kilo (thousand), Hecto (100), Deka (10), Deci (1/10), Centi (1/100) Milli (1/1000), Micro (1/million), Nano (1/billion), Pico (1/trillion)

Uncertainty in Measurements A. Measurements always have some amount of uncertainty based on the measuring device 4.35 cm B. Correct measurements always have one “uncertain number”

Significant Figures Rules for Identifying: All non-zero #’s are significant Zeros only significant if between numbers or behind numbers with decimal visible anywhere (202), (0.020), (200.), (200) 3. Exact numbers (obtained from counting or from definitions) (12 in a dozen, 60 min. = 1 hour) have infinite sig. figs.

Underline the Significant Figures 2,000 m 202,000 mm 3.000 kg 0.00300 atm 400.C 8.90x102 mL 0.5 mol 0.002 M

Sig. Fig. Calculations Multiplication/Division Depends on smallest # of sig. figs Ex. 10.5 x 0.5 = 5.25 which we round to 5 (1 s.f.) Addition/Subtraction Depends on smallest # of decimal spaces Ex. 10.5 + 0.5 = 11 but we make it 11.0 to have 1 decimal point

Calculate These Using Significant Figure Rules 13.5 + 1.06 = 10.6 x 2 = 100 – 9.5 = 1500  3.54 =

Conversions Use equivalence to compare two units Ex. 2000 Centimeters  kilometers If the units match, then you are done, perform the math 2000 cm 1 meter 1 kilometer = kilometers 0.02 1000 meter 100 cm

Temperature Fahrenheit scale based on human body temp. (ºF-32) x (5/9) = ºC Celsius scale based on boiling/freezing water ºC x (9/5) + 32 = ºF Kelvin scale based on absolute zero (theoretical temp. when motion stops) ºC + 273.15 = K

Density Density = mass/volume Usually in grams/cm3 or g/mL Depends on compactness of an object