Chapter 1 Introduction to Chemistry by Christopher Hamaker © 2011 Pearson Education, Inc. Chapter 1

Evolution of Chemistry The History of Chemistry in 15 Minutes http://www.youtube.com/watch?v=RTnTEPaIU3Q Chemistry - Greatest Discoveries [HD] (45 min) http://www.youtube.com/watch?v=L1_EXsAqGvI © 2011 Pearson Education, Inc. Chapter 1

Evolution of Chemistry The Greeks believed in four basic elements: 1. Earth Air Fire Water All substances were combinations of these four basic elements. © 2011 Pearson Education, Inc. Chapter 1

Scientific Investigations Science is the methodical exploration of nature followed by a logical explanation of the observations. Scientific investigation entails the following activities: Planning an investigation Carefully recording observations Gathering data Analyzing the results © 2011 Pearson Education, Inc. Chapter 1

The Discovery Process Chemistry - The study of matter… Matter - Anything that has mass and occupies space. This desk A piece of Aluminum foil What about air? Yes it is matter.

Chemistry Chemistry is the study of matter. Matter is anything that has mass and takes up space. Matter can change from one form to another. In a chemical change (chemical reaction), substances are used up and others formed in their place. Example: When propane (bottled or LP gas) burns in air, propane and oxygen are converted to carbon dioxide and water. In a physical change, matter does not lose its identity. A common physical change is a change of state. Example: Ice (solid water) melts to become liquid water; liquid water boils to become steam (gaseous water).

Chemistry - The study of matter and the changes it undergoes. Chemical and physical changes Energy changes Energy - The capacity to do work to accomplish some change.

The Scientific Method The scientific method is a systematic investigation of nature and requires proposing an explanation for the results of an experiment in the form of a general principle. The initial, tentative proposal of a scientific principle is called a hypothesis. After further investigation, the original hypothesis may be rejected, revised, or elevated to the status of a scientific principle. © 2011 Pearson Education, Inc. Chapter 1

Applying the Scientific Method Step 1: Perform a planned experiment, make observations, and record data. Step 2: Analyze the data and propose a tentative hypothesis to explain the experimental observations. Step 3: Conduct additional experiments to test the hypothesis. If the evidence supports the initial proposal, the hypothesis may become a theory. © 2011 Pearson Education, Inc. Chapter 1

Scientific Method Fact: A statement based on direct experience Hypothesis: A statement that is proposed, without actual proof, to explain a set of facts or their relationship. Theory: The formulation of an apparent relationship among certain observed phenomena, which has been verified to some extent. In a sense, a theory is the same as a hypothesis except that we have a stronger belief in it because more evidence supports it. If, however, we find new evidence that conflicts with the theory, it must be altered or rejected.

Applying the Scientific Method, Continued After sufficient evidence, a hypothesis becomes a scientific theory. A natural law is a measurable relationship. © 2011 Pearson Education, Inc. Chapter 1

Observation of a phenomenon A question A hypothesis (a potential answer) Experimentation Theory New hypothesis Further experimentation Development of new experimentation and theory

Critical Thinking: Reactions with Oxygen What do burning wood, rusting iron, and exploding gasoline have in common? All three are examples of combustion. Combustion is a chemical reaction of a substance with oxygen. Rusting is a slow reaction, burning is a rapid reaction, and an explosion is an instantaneous reaction. © 2011 Pearson Education, Inc. Chapter 1

Modern Chemistry Chemistry is a science that studies the composition of matter and its properties. Chemistry is divided into several branches: Organic chemistry is the study of substances containing carbon. Inorganic chemistry is the study of all other substances that don’t contain carbon. Biochemistry is the study of substances derived from plants and animals. © 2011 Pearson Education, Inc. Chapter 1

Learning Chemistry Different people learn chemistry differently. What do you see in the picture? Some people see a vase on a dark background; some people see two faces. © 2011 Pearson Education, Inc. Chapter 1

Problem Solving Connect the dots using only four straight lines. Experiment until you find a solution. Did you have to use five straight lines? No matter which dot we start with, we still need five lines. © 2011 Pearson Education, Inc. Chapter 1

Problem Solving, Continued Are we confining the problem? We need to go beyond the nine dots to answer the problem. © 2011 Pearson Education, Inc. Chapter 1

Chemistry: The Central Science Knowledge of chemistry is important to understanding the world around us. © 2011 Pearson Education, Inc. Chapter 1

Chapter Summary Scientists use the scientific method to investigate the world around them. Experiments lead to a hypothesis, which may lead to a scientific theory or a natural law. Chemistry is a central science with many branches. The impact of chemistry is felt in many aspects of our daily lives. © 2011 Pearson Education, Inc. Chapter 1

no systematic correlation between measurements. ENGLISH AND METRIC UNITS English system - a collection of measures accumulated throughout English history. no systematic correlation between measurements. 1 gal = 4 quarts = 8 pints Metric System - composed of a set of units that are related to each other decimally. That is, by powers of tens

1 meter = 10 decimeters = 100 centimeters Truly systematic 1 meter = 10 decimeters = 100 centimeters Basic Units of the Metric System Mass gram g Length meter m volume liter L prefixes are used to indicate the power of ten used

Metric System Table 1.1 Base units in the metric system

Conversion Table 1.2 Common Relationships Used in the English System A. Weight 1 pound = 16 ounces 1 ton = 2000 pounds B. Length 1 foot = 12 inches 1 yard = 3 feet 1 mile = 5280 feet C. Volume 1 gallon = 4 quarts 1 quart = 2 pints 1 quart = 32 fluid ounces Table 1.3 Commonly Used “Bridging” Units for Intersystem Conversion Quantity English Metric Mass 1 pound = 454 grams 2.2 pounds = 1 kilogram Length 1 inch = 2.54 centimeters 1 yard = 0.91 meter Volume 1 quart = 0.946 liter 1 gallon = 3.78 liters

Metric System Table 1.2 The Most Common Metric Prefixes

Think Metric!!!!!!! 10E-12 boos = 1 picoboo 1boo E2 = 1 boo boo 10 E1 cards = 1decacards 10 E-2 menals = 1 centimental 10 E6 phones = 1 megaphone 10 E-6 phones = 1 microphone 10 E3 joys = 1 kilo-joy

The milliliter and the cubic centimeter are equivalent

Metric unit is the second Time Metric unit is the second Temperature - the degree of “hotness” of an object

Temperature Fahrenheit (F): Defined by setting the normal freezing point of water at 32°F and the normal boiling point of water at 212°F. Celsius (C): Defined by setting the normal freezing point of water at 0°C and the normal boiling point of water at 100°C. Kelvin (K): Zero is the lowest possible temperature; also called the absolute scale. Kelvin degree is the same size as a Celsius degree K = °C + 273

Conversions between Fahrenheit and Celsius 1. Convert 75oC to oF. 2. Convert -10oF to oC. 1. Ans. 167 oF 2. Ans. -23oC

within the metric system between the English and metric system UNIT CONVERSION You need to be able to convert between units within the metric system between the English and metric system The method used for conversion is called the Factor-Label Method or Dimensional Analysis !!!!!!!!!!! VERY IMPORTANT !!!!!!!!!!!

For example: How many donuts are in one dozen? Let your units do the work for you by simply memorizing connections between units. For example: How many donuts are in one dozen? We say: “Twelve donuts are in a dozen.” Or: 12 donuts = 1 dozen donuts What does any number divided by itself equal? ONE! or...

This fraction is called a unit factor What does any number times one equal? That number.

a number divided by itself = 1 We use these two mathematical facts to do the factor label method a number divided by itself = 1 any number times one gives that number back Example: How many donuts are in 3.5 dozen? You can probably do this in your head but let’s see how to do it using the Factor-Label Method.

Factor-Label Method Conversion factor: A ratio of two different units, used as a multiplier to change from one system or unit to another. For example, 1 lb = 453.6 g Example: Convert 381 grams to pounds. Example: Convert 1.844 gallons to milliliters.

Factor-Label Method Dimensional Analysis/Factor Label Method - Chemistry Tutorial (11.14 min) http://www.youtube.com/watch?v=DsTg1CeWchc Unit conversion (9:17 min) http://www.youtube.com/watch?v=w0nqd_HXHPQ Conversion between metric units (5:16) http://www.youtube.com/watch?v=SYkmadc2wOI Unit Conversion Example: Drug Dosage (10:44) http://www.youtube.com/watch?v=ScvuRb6vsz4

Examples of Unit Conversion 1. Convert 5.5 inches to millimeters 2. Convert 50.0 milliliters to pints 3. Convert 1.8 in2 to cm2