Unit 3 Matter and Its Transformations

Transcription

1 Unit 3 Matter and Its Transformations What is chemistry? (Introduction to Chapter 1) Physical and chemical properties (1.8) Physical and chemical changes (1.8) Classification of matter (1.9)

2 What is Chemistry? (Intro to Chapter 1) Matter anything that occupies space and has a mass (1.8) Chemistry the study of matter and its transformations (Introduction to Chapter 1)

3 Physical and Chemical Properties (1.8) Physical property a physical characteristic or behavior of the material Examples: boiling point, hardness, color Chemical property describes how the material reacts with (or doesn t) with other types of matter Examples: iron rusts in moist air, hydrogen and oxygen react violently, neon does not react with anything

4 Physical and Chemical Changes (1.8) Physical change a change in the appearance of a substance without changing its chemical identity or composition Examples: melting ice, cutting a piece of wood in half Chemical change a change in the chemical identity of matter into other substances that are different Examples: hydrogen and oxygen react to form water, a piece of iron rusts,

5 Classification of Matter (1.9) With over 18 million characterized compounds, categorization is important to provide a framework for study This initial classification system provides a good starting point As you might imagine, there are subclassifications under many of these basic groupings

6 States of Matter (1.9) Three common states of matter (plus a bonus): Gas takes shape of container, flows easily, compressible Liquid takes shape of container but with a flat top, flows easily, not very compressible Solid retains shape, does not flow appreciably, not very compressible (A bonus state: plasma a stream of charged particles this is the stuff of plasma TV)

7 Particle Level Description of States of Matter Gas: Particles far apart Particles moving rapidly Notice that as the temperature decreases the particles get closer together Liquid: Particles close together Particles moving slowly Particles more ordered than gas, but not as much as solid Solid: Particles close together Particles only vibrating Particles very ordered Images are screen shots from States of Matter simulation PhET Interactive Simulations University of Colorado

8 Pure Substances and Compounds (1.9) Pure substance has a definite fixed composition that does not vary from one sample to another Examples: pure copper, pure water Mixture variable composition that can be different from one sample to another Examples: salt water, air, sand and water mixed together

9 Further Classification of Pure Substances Pure substances can further be categorized as: Elements substance which cannot be broken down into simpler substances by chemical means Compounds chemical combination of two or more elements

10 Periodic Table the elements A sample periodic table - if it s a known element it is on here. Compounds are chemical combinations of multiple elements. A large portion of our course will be involved with studying the periodic chart. Periodic table from common.wikimedia.org

11 Further Classification of Mixtures Mixtures can further be categorized as: Homogeneous all parts of the mixture have the same composition and appearance Examples: sugar dissolved in water, air, a pinch of salt dissolved in water Heterogeneous appearance is not the same throughout Examples: sand in water, oil in water

12 Summary of Classification of Matter Matter Pure Substances Mixtures Elements Compounds Homogeneous Mixtures Heterogeneous Mixtures