Chapters 2,3,4,6,7,12,13 PDF

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Summary

These are notes during Professor Stacey Littlejohn's summer semester....

Description

Units of Measurement (2.1) International System of Units (SI): An official system of measurement used throughout the world for units of length, volume, mass, temperature, and time

Volume: The space occupied by a substance -

SI unit: m3 Metric unit: Liter (L) and Milliliter (mL)

Length: Measured by observing the marked lines at the end of a ruler - Metric and SI units: Meter (m) and Centimeter (cm)

Mass: A measure of the quantity of material an object contains - SI unit: Kilogram (kg) - Metric unit: gram (g)

Temperature: Tells us how hot or cold something is - SI unit: Kelvin (K) - The Kelvin scale for temperature begins at the lowest possible temperature, 0°K - Metric unit: Celcius (℃)

Time

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SI and Metric unit: Second (s)

Measured Numbers and Significant Figures (2.2) Measured Numbers: The numbers obtained when you measure a quantity such as height or weight - To write a measured number: - Observe the numerical values of the marked lines (keep all certain digits) - Estimate the value of the number between the marks (only write 1 estimated digit) - The estimated number is the final number in your measured number Significant Figures (SFs) - Used to represent the amount of error associated with a measurement - SFs are all non-zero digits and zeros between digits - SFs are zeros at the end of a decimal number - SFs are not zeros that act as placeholders before digits - In a measured number, SFs are all the digits, including the estimated digit

Significant Zeros & Scientific Notation - When one or more zeros in a large number are significant, they are shown clearly by writing the number in scientific notation - Ex: If only the first zero in the measurement 300m is a significant zero, but the second zero is not, it will be written as 3.0 x 102 m - Zeros at the end of large standard numbers without a decimal point are not significant - Ex: 400,000 is written with one SF as 4 x 105 g - Zeros at the beginning of a decimal number are used as placeholders and are not significant - Ex: 0.0004 s is written with one SF as 4 x 10-4 s Exact Numbers

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Not measured and do not have a limited number of significant figures Not used to find the number of significant figures in a calculated answer Numbers obtained by counting Definitions that compare two units Definitions in the same measuring system

Significant Figures in Calculations (2.3) Rules for Rounding Off 1) If the first digit to be dropped is 4 or less, then it and all the following digits are dropped from the number 2) If the first digit to be dropped is 5 or greater, then the last retained digit of the number is increased by 1

Multiplication & Division: Measured Numbers - In multiplication or division, the final answer is written so that it has the same number of SFs as the measurement with the fewest SFs

Adding

Significant Zeros - When the calculator display contains fewer SFs than needed, add one or more significant zeros to obtain the correct number of SFs

Addition & Subtraction with Measured Numbers - In addition or subtraction, the final answer is written so that it has the same number of decimal places as the measurement with the fewest decimal places

Prefixes and Equalities (2.4) Prefixes: Can be placed in front of any unit to increase or decrease its size by some factor of ten - The relationship of a prefix to a unit can be expressed by replacing the prefix with its numerical value - Ex: When the prefix kilo in kilometer is replaced with its value of 1000, we find that a kilometer is equal to 1000 miles

Prefixes to Memorize

Measuring Length - Each of the following equalities describes the same length in a different unit:

Measuring Volume - Volumes of 1L or smaller are common in the health sciences - When a liter is divided into 10 equal portions, each portion is called a Deciliter (dL)

The The cube with dimensions of 1cm on each side - Abbreviated as cm3 or cc

Measuring Mass

Writing Conversion Factors (2.5) Equalities: Use two different units to describe the same measured amount

Conversion Factors: An equality written as a fraction

Cubic Centimeter: volume of a

Common Equalities to Know

Metric Conversion Factors - In the example below, both are proper conversion factors for the relationship; one is just the inverse of the other

Conversion Factors: Percentage - A percentage is written as a conversion factor by choosing a unit and expressing the numerical relationship of the parts of this unit to 100 parts of the whole

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To indicate very small ratios, we use parts per million (ppm) or parts per billion (ppb)

Problem Solving Using Unit Conversion (2.6) Dimensional Analysis: A method of problem-solving that allows you to change one unit into another unit

Using Two or More Conversion Factors - Often needed to complete the change of units

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In setting up these problems, one factor follows the other Each factor is arranged to cancel the preceding unit until the needed unit is obtained

Example #2

Density (2.7) Density: Compares the mass of an object to its volume - Objects that sink in water are denser than water - Objects that float in water are less dense than water...