General Chemistry Lecture

Post on 12-Jan-2016

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Scientific Measurements

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Scientific Measurements

1. All numbers excluding the zero are significant.

2. Zero is significant if it is between 2 non-zero digits.

3. Zero’s to the right of an expressed decimal points are significant.

4. Zero’s to the right of a decimal point and to the right of a non-zero digit is significant

Significant Figures Rules

Significant Figures Rules

5. Zero’s with bar on the top are significant.6. Zero’s to the left of a decimal point but to the left of a non-zero decimal are not significant.7. When a number ends with a zero, the zeros are not significant

• Addition and Subtraction–Least Decimal Places

• Multiplication and Division–Least Significant figures

Operations on Significant Figures

- Short hand way of writing large and small numbers

- (+ large numbers), base (- decimal numbers)- Example:- Mass of an electron

0.00000000000000000000000000000911or

Speed of light :

Scientific Notation

Operation on Scientific Notation

Addition1. If the same exponent, add the main and

copy the exponent2. If not the same exponent, make the same

exponent copying the larger exponent

Operation on Scientific Notation

Subtraction1. If the same exponent, subtract the main and

copy the exponent2. If not the same exponent, make the same

exponent copying the larger exponent

Operation on Scientific Notation

MultiplicationMultiply the M’s (bases) and add the

exponents algebraically

DivisionDivide the M’s and subtract the

exponents algebraically

Length10mm=1cm 1yard=3ft10cm=1dcm 1km=0.62miles10dcm=1m10m=1hm10hm=1km1inch=2.54cm12inches=1ft

Conversion

Mass1g=1000mg1000g=1kg1kg=2.2lb

Volume1L=1000mL1cm³=1mL=1cc

Conversion

Temperature

°C → °F °F = °C +32K= °C +273.15R=°F + 460.67

Conversion

Prepared by:Novilyn M. Villanueva