Section 2.1 Units and Measurements

Slides:



Advertisements
Similar presentations
Section 2.1 Units and Measurements
Advertisements

Section 2.2 – Units of Measurement
Chapter 2 Measurements and Calculations.
Section Units of Measurement
Analyzing Data Chapter 2.
Click a hyperlink or folder tab to view the corresponding slides.
Chapter 2 Data Analysis.
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
SI units, metric units, scientific notation, and dimensional analysis
METRIC AND MEASUREMENTS Scientific Notation Significant Digits Metric System Dimensional Analysis.
Measurements and Calculations
Click a hyperlink or folder tab to view the corresponding slides.
Analyzing Data. Units and Measurements  Units  Système Internationale D’Unités ▪ Units were not always exact ▪ Scientists report data, and this data.
Why do we need it? Because in chemistry we are measuring very small things like protons and electrons and we need an easy way to express these numbers.
Section 2.2.
CHEMISTRY Matter and Change
Section 2.1.
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
Section 2.1 Units and Measurements
Chapter 2: analyzing data
Scientific Units 1.2 Notes Part B. Unit Objectives Use appropriate SI units for length, mass, time, temperature, quantity, area, volume and density. (ACT.
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
Section 5.1 Scientific Notation and Units 1.To show how very large or very small numbers can be expressed in scientific notation 2.To learn the English,
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
Chapter 2 Data Analysis. I. SI Units Scientists adopted a system of standard units so all scientists could report data that could be reproduced and understood.
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
Unit 2: Units and Measurements
The SI System of Measurement
Scientific Notation.
Scientists need to report data that can be reproduced by other scientists. They need standard units of measurement. SI Units Data Analysis: Basic Concepts.
Matter And Measurement 1 Matter and Measurement. Matter And Measurement 2 Length The measure of how much space an object occupies; The basic unit of length,
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
Slide 1 of 33 International System of Units 3.2. Slide 2 of 33 © Copyright Pearson Prentice Hall The International System of Units > 3.2 Measuring with.
METRIC AND MEASUREMENTS Scientific Notation Significant Digits Metric System Dimensional Analysis.
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
Chapter 2 Analyzing Data. Scientific Notation & Dimensional Analysis Scientific notation – way to write very big or very small numbers using powers of.
Topic 3 Topic 3 Topic 3: Data Analysis Table of Contents Topic 3 Topic 3.
1 Chapter 2 Analyzing Data Section 2.1 Units and Measurement Essential Questions: What are some SI base units and derived units How does adding a prefix.
Chemists use an internationally recognized system of units to communicate their findings. Section 1: Units and Measurements K What I Know W What I Want.
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
Section 2-1 Units Système Internationale d'Unités (SI) is an internationally agreed upon system of measurements. A base unit is a defined unit in a.
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
Chapter Menu Analyzing Data Section 2.1Section 2.1Units and Measurements Section 2.2Section 2.2 Scientific Notation and Dimensional Analysis Section.
Math Toolkit. Système Internationale d'Unités (SI) is an internationally agreed upon system of measurements. A base unit is a defined unit in a system.
A Systematic Approach The experimental design is a systematic approach used in scientific study, whether it is chemistry, physics, biology, or another.
Section 2.1 Units and Measurements
Click a hyperlink or folder tab to view the corresponding slides.
Click a hyperlink or folder tab to view the corresponding slides.
Click a hyperlink or folder tab to view the corresponding slides.
Lecture 3 Units and Measurements August 20, 2010 Ozgur Unal
Section 2.1 Units and Measurements
Click a hyperlink or folder tab to view the corresponding slides.
Chapter 3: Measurement: SI and Metric
Click a hyperlink or folder tab to view the corresponding slides.
Scientific Measurement
CHEMISTRY Matter and Change
Click a hyperlink or folder tab to view the corresponding slides.
Chapter 2 Data Analysis.
Test 2: Standards of Measurement
Click a hyperlink or folder tab to view the corresponding slides.
Click a hyperlink or folder tab to view the corresponding slides.
Click a hyperlink or folder tab to view the corresponding slides.
Click a hyperlink or folder tab to view the corresponding slides.
Section 1: Units and Measurements
Section 1: Units and Measurements
Chapter 2 Analyzing Data
Units Système Internationale d'Unités (SI) is an internationally agreed upon system of measurements. A base unit is a defined unit in a system of measurement.
Presentation transcript:

Section 2.1 Units and Measurements Define SI base units for time, length, mass, and temperature. Explain how adding a prefix changes a unit. Compare the derived units for volume and density. mass: a measurement that reflects the amount of matter an object contains Section 2-1

Section 2.1 Units and Measurements (cont.) base unit second meter kilogram kelvin derived unit liter density Chemists use an internationally recognized system of units to communicate their findings.

Units Système Internationale d'Unités (SI) is an internationally agreed upon system of measurements. A base unit is a defined unit in a system of measurement that is based on an object or event in the physical world, and is independent of other units. There are seven base units in SI. All other units are derived from a combination of these base units.

Units (cont.) Table on p. 33 of your textbook

Units (cont.) Table on p. 33 of your textbook

Prefix Symbol Numerical value in base units Power of 10 equivalent Giga G 1,000,000,000 109 Mega M 1,000,000 106 Kilo K 1000 103 Hecto h 100 102 Deka da 10 101 --- ---- 1 (base) Deci d 0.1 10-1 Centi c 0.01 10-2 Milli m 0.001 10-3 Micro μ 0.000001 10-6 Nano N 0.000000001 10-9 Pico P 0.000000000001 10-12

Units (cont.) The SI base unit of time is the second (s), based on the frequency of radiation (the time for a large number of vibrations) given off by a cesium-133 atom. The SI base unit for length is the meter (m), the distance light travels in a vacuum in 1/299,792,458th of a second.

How many milligrams are in a gram? The SI base unit of mass is the kilogram (kg). This weighs about 2.2 pounds. The kilogram is an actual physical standard of platinum and iridium. Scientists are working to redefine this. Mass and weight are two different things. Because the kilogram is a large unit of measure, in the lab we will usually measure grams. How many milligrams are in a gram? Mass is a measure of how much “stuff” there is….the amount of matter in an object. If you go to the moon, your weight changes, but your mass does not.

Units (cont.) The SI base unit of temperature is the kelvin (K). Zero kelvin is the point where there is virtually no particle motion or kinetic energy, also known as absolute zero. You may be more familiar with the Celsius scale. This scale was set up based on the boiling and freezing of water. On this scale, water freezes at 0°C and boils at 100°C. In lab, we will measure Celsius degrees.

To convert from Celsius to Kelvin, the formula is: K = °C + 273 Example: Water boils at 100 °C. What temperature is that on the Kelvin scale? Example 2: A metal has a temperature of 423 K. What temperature is that in degrees Celsius?

Two other temperature scales are Celsius and Fahrenheit. To convert from Celsius to Fahrenheit, the formula is: °F = 1.8(°C) + 32 Example 3: If the temperature outside is 25 °C, what temperature is that in Fahrenheit?

Derived Units Not all quantities can be measured with SI base units. A unit that is defined by a combination of base units is called a derived unit. For example, the standard unit for speed in the metric system is m/s. This unit is derived by dividing the SI unit for length (meter) by the SI unit for time (second).

Derived Units (cont.) Volume is measured in cubic meters (m3), but this is very large. A more convenient measure is the liter, or one cubic decimeter (dm3).

Density is a derived unit, g/cm3, the amount of mass per unit volume. Derived Units (cont.) Density is a derived unit, g/cm3, the amount of mass per unit volume. The density equation is density = mass/volume. Example: Find the density of a metal box that has a volume of 5 cm3 and a mass of 44.6 grams. From page 971, what type of box is it? D =

A B C D Section 2.1 Assessment Which of the following is a derived unit? A. yard B. second C. liter D. kilogram A B C D Section 2-1

A B C D Section 2.1 Assessment What is the relationship between mass and volume called? A. density B. space C. matter D. weight A B C D Section 2-1

Section 2.2 Scientific Notation and Dimensional Analysis Express numbers in scientific notation. Convert between units using dimensional analysis. quantitative data: numerical information describing how much, how little, how big, how tall, how fast, and so on Section 2-2

Section 2.2 Scientific Notation and Dimensional Analysis (cont.) conversion factor Scientists often express numbers in scientific notation and solve problems using dimensional analysis. Section 2-2

Scientific Notation Scientific notation can be used to express any number as a number between 1 and 10 (the coefficient) multiplied by 10 raised to a power (the exponent). Count the number of places the decimal point must be moved to give a coefficient between 1 and 10. Section 2-2

Scientific Notation (cont.) The number of places moved equals the value of the exponent. The exponent is positive when the decimal moves to the left and negative when the decimal moves to the right. 800 = 8.0  102 0.0000343 = 3.43  10–5 Example: Express 123 456 in scientific notation. Section 2-2

Scientific Notation (cont.) Addition and subtraction Exponents must be the same. Rewrite values with the same exponent. Add or subtract coefficients. Examples: Add 1.23 x 103 and 2.46 x 103 Add 2.2 x 102 and 3.33 x 103 (or…use your calculator!) Section 2-2

Scientific Notation (cont.) Multiplication and division To multiply, multiply the coefficients, then add the exponents. To divide, divide the coefficients, then subtract the exponent of the divisor from the exponent of the dividend. Section 2-2

Dimensional Analysis Dimensional analysis is a systematic approach to problem solving that uses conversion factors to move, or convert, from one unit to another. A conversion factor is a ratio of equivalent values having different units. Section 2-2

Dimensional Analysis (cont.) Writing conversion factors Conversion factors are derived from equality relationships, such as 1 dozen eggs = 12 eggs. Percentages can also be used as conversion factors. They relate the number of parts of one component to 100 total parts. Section 2-2

Dimensional Analysis (cont.) Using conversion factors A conversion factor must cancel one unit and introduce a new one. This is an example that shows how to use conversion factors in finding how many 8 packs of soda you would need for a party of 32 people, assuming each person drinks 2 bottles of soda. Section 2-2

Examples: Use conversion factors to make the following conversions: 240 s to ms. 46 kg to Mg.

A B C D Section 2.2 Assessment What is a systematic approach to problem solving that converts from one unit to another? A. conversion ratio B. conversion factor C. scientific notation D. dimensional analysis A B C D Section 2-2

A B C D Section 2.2 Assessment Which of the following expresses 9,640,000 in the correct scientific notation? A. 9.64  104 B. 9.64  105 C. 9.64 × 106 D. 9.64  610 A B C D Section 2-2