3 Section 1.1 Chemistry OBJECTIVE: Students will be able to describe the purpose of studying chemistry.
4 What is Chemistry? Chemistry is the study of “matter” – Matter is anything with mass and occupies spaceWhat qualifies as matter?What does not qualify as matter?
5 5 Major Areas of Chemistry Analytical Chemistry- concerned with the composition of substances.Inorganic Chemistry- primarily deals with substances without carbonOrganic Chemistry- essentially all substances containing carbonBiochemistry- Chemistry of living thingsPhysical Chemistry- describes the behavior of chemicals (ex. stretching); involves lots of math!Boundaries not firm – they overlap and interact
7 What is Chemistry?Pure chemistry- gathers knowledge for the sake of knowledgeApplied Chemistry- is using chemistry to attain certain goals,in fields like medicine, agriculture, and manufacturing – leads to an application
8 Why Study Chemistry?Everyone and everything around us involves chemistry – explains our worldHelps you make choices; helps make you a better informed citizenA possible career for your future
9 Section 1.3 Scientific Method OBJECTIVE:Students will be able to derive the steps of the scientific method from their knowledge of science.
10 The Scientific MethodA logical approach to solving problems or answering questions.Starts with observation- noting and recording information and factshypothesis- a proposed explanation for the observation; must be tested by an experiment
11 Steps in the Scientific Method 1. Observations (uses your senses)a) quantitative involves numbers = 95oFb) qualitative is word description = hot2. Formulating hypotheses (ideas)- possible explanation for the observation, or “educated” guess3. Performing experiments (the test)- gathers new information to help decidewhether the hypothesis is valid
12 Scientific Method“controlled” experiment- designed to test the hypothesisonly two possible answers:hypothesis is righthypothesis is wrongWe gather data and observations by doing the experimentModify hypothesis - repeat the cycle
13 Scientific MethodWe deal with variables, or factors that can change. Two types:1) Manipulated variable (or independent variable) is the one that we change2) Responding variable (or dependent variable) is the one observed during the experimentFor results to be accepted, the experiment needs to always produce the same result
14 Outcomes over the long term… Theory (Model)- A set of well-tested hypotheses that give an overall explanation of some natural phenomenon – not able to be provedNatural Law (or Scientific Law)- The same observation applies to manydifferent systems; summarizes results- an example would be:the Law of Conservation of Mass
15 A law summarizes what has happened. Law vs. TheoryA law summarizes what has happened.A theory (model) is an attempt to explain why it happened – this changes as new information is gathered.
16 - Page 22Using your senses to obtain informationThe procedure that is used to test the hypothesisHypothesis is a proposed explanation; should be based on previous knowledge; an “educated” guessTells what happenedA well-tested explanation for the observations; cannot be proven due to new discoveries
17 Section 1.4 Problem Solving in Chemistry OBJECTIVES:Students will be able to determine the appropriate problem solving technique for every type of problem.
18 Problem Solving in Chemistry You don’t need to write any of this Problem Solving in Chemistry You don’t need to write any of this. These are just points for discussion.In Chemistry we are faced with problems we need to solve like in lifeHow should we approach problems?There is a problem solving method that needs to be learned.
19 Solving Numeric Problems Measurements are an important part of chemistry; thus many of our word problems involve use of mathematicsWord problems are real life problems, and sometimes more information is presented than needed for a solution
20 Solving Numeric Problems The three steps we will use for solving a numeric word problem are:AnalyzeCalculateEvaluateLet’s learn how to ACE these numeric word problems!
21 Solving Numeric Problems 1. Analyze: this is the starting pointDetermine what are the known factors, and write them down on your paper!Determine what is the unknown. If it is a number, determine the units neededPlan how to relate these factors- choose an equation; use table or graphThis is the heart of successful problem solving techniques – it is the PLAN
22 Solving Numeric Problems 2. Calculate: perform the mathematicsIf your plan is correct, this is the easiest step.Use a calculator and do it correctly!May involve rearranging an equation or doing some conversion of units to some other units.
23 Solving Numeric Problems 3. Evaluate: – the finishing stepIs it reasonable? Make sense? Check your calculations.Do you need to round off the answer?Do you need scientific notation?Do you have the correct units?Did you answer the question?
24 Solving Conceptual Problems Not all word problems in chemistry involve doing calculationsNonnumeric problems are called conceptual problems – ask you to apply concepts to a new situationSteps are:1) Analyze and 2) SolveDo Conceptual Problem 2.1 on page 46