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Cheatography

Signif­icant Figures

Signif­icant Figures: Digits in a measur­ement that can be determined accurately plus one that is estimated and is therefore uncertain.

-All non-zero digits are always signif­icant
446= sig figs
-Zeros:
#1-Zeros at the beginning of numbers( are never signif­icant)
=0.678-3 sig figs
#2-Zeros b/n non-zero digits are always signif­icant
=706-3 sig figs
#3- Zeros at the end of numbers are only considered sig figs if there is a decimal point in the number or at the end of the number
=760-2 sig figs
=760.0-4 sig figs

Exact Numbers: Numbers that are counted not obtained using measuring devices have infinite sig figs.(Most conversion factors are exact numbers)

Scientific Notation: For values written in Scientific notation, the digits in the coeffi­cient (numbers without an exponent).
=1.500­*10^4-4 sig figs
Scientific notation in Conversion rules
#1=Move the decimal point to the position so one non-zero digit is to the left of the decimal point
#2=If the decimal point is moved to the right, the exponent is positive
#3=If the decimal point is moved to the left, the exponent is negative
 

Rounding Adding­,Su­btr­act­ing­,Di­vid­ing­,Mu­lti­plying

Rounding using Sig Figs
-5 or greater will round up to the next digit
-4 or less will be rounded down
=1234.5 to 4 sig figs-1235

Calcul­ating using Sig Figs
Multip­lic­ati­on/­Div­ision
#1= Answer should have the same number of signif­icant as the measur­ement with the fewest sig figs
=1.35*­0.0­4-0.05­36-0.05 (Least number has 1 sig figs so you round the answer to 1 sig fig)
Additi­on/­Sub­tra­ction
#1=The answer should have the same number of decimal places as the least precise measur­ement (Look at the place value of the least precise)
=1.34+­2.3­=3.6­4-3.6 (10th is the least so answer should only go up to the 10th
 

Density and Percent Error

Density
Mass/V­olume= Density
Intensive physical property: Doesn't change with increase in amount.
Volume
Liquids=ml
Solids=cm3

Percent error
Quanti­tative comparison of the experi­mental value to the correct or accepted value. % error is negative when experi­mental is smaller than actual.

% Error=­(Ex­per­ime­nt-­Actual Value/­Actual Value)*100
 

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