Unit 1 Chapters 1 and 3

Chapter 1 Chemistry: An Introduction

What is chemistry? Chemistry-the science that deals with the materials of the universe and the changes that these materials undergo. Goal of chemistry-to understand the connection between the macroscopic world and the microscopic world.

Copyright © Houghton Mifflin Company. All rights reserved.1–41–4 Macroscopic

Copyright © Houghton Mifflin Company. All rights reserved.1–51–5 Microscopic Each grain of sand is composed of tiny atoms

Scientific method. l A way of solving problems Step 1: Observation-what is seen or measured Step 2: Hypothesis-educated guess of why things behave the way they do. (possible explanation) Step 3: Experiment-designed to test hypothesis, leads to new observations l The cycle continues

Scientific method. l After many cycles, a broad, generalizable explanation is developed for why things behave the way they do l Theory-explains a phenomenon l Law-summary of observations

Scientific method. l Theories have predictive value. l The true test of a theory is if it can predict new behaviors. l If the prediction is wrong, the theory must be changed. l Theory- why something happens l Law – what happens

Observations Hypothesis Experiment Law Theory (Model) Prediction Experiment Modify

Find My Rule

What do these have in common? Yes l She got $3 in change. l Frank weighs 150lb. l The man was 6 feet tall. l Ice melts at 0°C. l It was November 22 l Miguel wears EEE width shoes. No l Chris ran quickly. l She grinned from ear to ear. l He was handsome. l She is taller than he is. l Her shirt was blue. l The chain saw was very loud.

Testers l John wears size 9 shoes. l The garage had a musty odor. l The solution was bright green. l The clouds were at feet. l The lemon was very sour. l people were at the game.

What do these have in common? Yes l Gasoline burns in a car engine. l An iron nail rusts. l A copper roof turns green. l Food is digested. l Photosynthesis occurs in a plant. l A silver spoon turns black. No l Wax on a candle melts. l Ice melts in a cold drink. l Frost forms on a window. l Water boils in a kettle. l Glass shatters. l Alcohol and water mix together.

Testers l Sugar is used by the body to produce energy. l Snow changes to water vapor. l Sugar dissolves in water. l Salt water evaporates to dryness. l Wood burns in a campfire. l Crazy Glue hardens when exposed to air.

Chapter 3: Matter

What is matter? l Matter-anything occupying space and having mass

Copyright © Houghton Mifflin Company. All rights reserved.1–17 The Three States of Matter

Copyright © Houghton Mifflin Company. All rights reserved.1–18 The Organization of Matter

Copyright © Houghton Mifflin Company. All rights reserved.1–19 Mercury and Iodine Combine to Form Mercuric Iodide

Law of Conservation of Mass The law of conservation of mass states that the total mass of materials in not affected by a chemical change.

Ways to separate mixtures l Filtration l Distillation l Chromatography *All of these are physical methods for separating components (i.e. the products are not changed chemically). **Remember phase changes are physical changes.

Filtration Used to separate the components of a mixture containing a solid and a liquid.

Simple Laboratory Distillation Apparatus Distillation depends on the volatility of the components Copyright © Houghton Mifflin Company. All rights reserved.1–23

Copyright © Houghton Mifflin Company. All rights reserved.1–24 C hromatography- A line of the mixture to be separated is placed at one end of a sheet. One phase is mobile ; one is stationary.

Copyright © Houghton Mifflin Company. All rights reserved.1–25 The paper acts as a wick to draw up the liquid.

Copyright © Houghton Mifflin Company. All rights reserved.1–26 The component with the weakest attraction for the paper travels faster.