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Chapter 1: The Scientific MethodChemistry = The science that seeks to understand what matter does by studying what atoms and molecules do.

1Observation = A way of acquiring information about nature. Simple descriptions (qualitative observation) Number (quantitative observation)Hypothesis = A tentative explanation of your observations Falsifiable: a test may invalidate your hypothesisExperiments = Tests of hypotheses, laws or theories Results either Validate (confirm) or Invalidate (deny) your ideasLaw = A statement that combines all past observations Predict future observations You cannot choose to violate a scientific lawTheory = An explanation that extends beyond individual observations to an understanding of the underlying causes for the way nature is or behaves Models of natureThis is what the scientific method is made ofObservation: anything wrong with this picture?

ObservationsHypothesisLawTheoryExperimentsExperimentsExperimentsThis is how the scientific method workshttp://www.youtube.com/watch?v=5Owji16tge0The (meaningful) beauty of the scientific method

Source: http://www.meaningfulbeauty.com/theStory.phpMeasurement = Quantitative observation Comparison to an agreed upon standard Every measurement has a number and a unitScientists have measured the average global temperature rise over the past century to be 0.6 C

The number tells youwhat multiple of the standard the object measuresthe uncertainty in the measurement

The unit tells you what standard you are comparing your object to

Chapter 2: Measurements and Problem SolvingScientific Notation is a way of writing large and small numbersThe suns diameter is1,392,000,000 mAn atoms average diameter is0.000 000 000 3 mThe suns diameter is1.392 x 109 mAn atoms average diameter is3 x 10-10 mLarge Number = Positive Exponent

1.392 x 109 mSmall Number = Negative Exponent

3 x 10-10 mWriting a number in scientific notation1,392,000,000 mLocate the decimal pointMove the decimal point until a numberbetween 1 and 10 is obtained Multiply the new number by 10nn is the number of places you moved the decimal pointLarge number? n is positiveSmall number? n is negative1,392,000,000. m1.392,000,000. m1.392 x 10 ? 9 m1.392 x 10 9 mSignificant Figures Writing Numbers to Reflect PrecisionExact Values Can be obtained by counting or by definition Exact values have unlimited significant figures

Measurements Are obtained from instruments The number of significant figures reflects the instrument precision. All the digits written are known with certainty except the last one, which is an estimate

1.2 gramsCertainEstimatedCounting Significant Figures0.003004500 mNon-zero digits are significantZeroes in between non-zero digits are significant Zeroes on the right of the last non-zero digit are significantZeroes on the left of the first non-zero digit are not significantImportant exception 1: Exact numbers.Numbers that come fromCountingFormulasAre not measurements and have an infinite amount of sig. fig.Important exception 2: Ambiguous numbers.A number has an ambiguous amount of sig. fig. if:It is bigger or equal to 10It has no decimalsIt ends with a zero10 Fingers >

100 MilesHow many significant figures are in each of the following numbers?

0.0035

1.080

2371

2.97 105

12 items (In a dozen)

100,000 Counting Significant Figures. Examples.Multiplication and Division with Significant FiguresWhen multiplying or dividing measurements with significant figures, the result has the same number of significant figures as the measurement with the fewest number of significant figures

5.02 89,665 0.10= 45.0118 = 45 3 sig. figs. 5 sig. figs. 2 sig. figs. 2 sig. figs.5.892 6.10= 0.96590 = 0.966 4 sig. figs. 3 sig. figs. 3 sig. figs.

Addition and Subtraction with Significant FiguresWhen adding or subtracting measurements with significant figures, the result has the same number of decimal places as the measurement with the fewest number of decimal places

5.74 + 0.823 +2.651= 9.214 = 9.21 2 dec. pl. 3 dec. pl. 3 dec. pl. 2 dec. pl.4.8 - 3.965= 0.835 = 0.8 1 dec. pl 3 dec. pl. 1 dec. pl.

The Standard UnitsScientists have agreed on a set of international standard units for comparing all our measurements called the SI unitsSystme International = International SystemQuantityUnitSymbollengthmetermmasskilogramkgtimesecondstemperaturekelvinK