Chapter Chemistry One Notes Chem= the study of matter and the changes it undergoes and the nrg associated with those changes. Scientific Method= Observations, hypothesis, experiment, model Matter Composition (components of their proportions) Substance- fixed composition (ie Element (one type of atom), cmpd (two or more elements) Mixture- (variable composition) (ie homogeneous (no visible boundaries), heterogeneous (visible bound) Changes Chemical (change in composition) Physical (change in form or state) NRG Kinetic NRG (nrg due to motion) Potential NRG (stored nrg due to position) (ie gravitational, mechanical, electrostatic, chemical) ** Lower nrg states are favored, nrg is conserved Physical Properties include melting pt, color, electrical conductivity, density Chemical Props include flammability, corrosiveness, reactivity w/ acids Extensive Properties- dependent upon the amt of substance present Intensive Properties- independent of amt
1km
1000 m
0.6214 mi
1 m 1 cm 1 m3 1 dm3 1 cm 1 kg 1 g 1 mile 1 yard 1 foot 1 inch 1 foot3 1 gallon 1 quart 1 quart fluid 1 ounce 1 pound 1 ounce 273.15
3
10 cm 1000mm .01 m 1000000 cm3 10000cm3 .001dm
3
1.094 yd 39.37 in .3937 in 35.31 ft3 .02642 gal 1.057 qt .03381 oz 2.205 lbs .03527 oz
1000 g 1000 mg 1.609 km 0.9144 m 0.3048 m 2.54 cm 0.02832 m3 3.785 dm3 0.9464 dm3 946.4 cm3 29.57 cm3 0.4536 kg 28.35 g
T (in K)= T (in Celcius) +
T (in C)= T (in K) 273.15 The greater the amt of sig figs in a measurement, the greater the certainty. Sig Figs= Start at left with first nonzero # and count all digits to right. If a number ends in zero, check decimal point. With decimals, the zeros listed after are included. In calculations, the least certain measurement sets the limit on certainity for the entire calculation and determines the # of sig figs in the final answer. In multiplication/division, use the amt for the measurement with the fewest sig figs
In addition/subtraction, the answer has the same # of decimal places as the measurement with the fewest decimal places. Measurements and Calculations Precision (reproucibility) Accuracy (closeness to actual value)