Physical and Chemical Properties and Changes

Physical and Chemical Properties and Changes • What is Matter • States of Matter • Chemical vs. Physical Properties • Qualitative vs. Quantitative Properties • Chemical vs. Physical Change • Energy How Your Lesson Works ØText that is bolded and underlined is blank on your student copy. When you see it, pause the video and copy it into your notes. ØWhenever a video is available, you will see the video icon and a number. Refer to your Additional Resource document to find the correct video link. While you’re watching the video, take a few jot notes on the main ideas that are covered. MATTER Chemistry Earth Sciences Biology Matter Physics Astronomy What is Matter? • Matter is any substance that has both mass (collection of particles) and volume (takes up space) • Almost everything around us is matter, including air and other gases • Energy is not matter States of Matter Solid Liquid Gas Solid vs. Liquid vs. Gas? 1 States of Matter Properties Shape Volume Compressibility Vibration Close about fixed together pt Definite Definite Can’t Liquid Free to move Close together Indefinite Definite A little Gas Free to move Far apart Indefinite Indefinite Can State Atomic/ Molecular Motion Solid Atomic/ Molecular Spacing 2 Changing States Gas Su bli ma tio n De po sit ion n tio riza po Va ion sat en nd Co Solid Freezing Melting Liquid Properties • Properties are the characteristics used to identify a substance • Examples include color, taste, smell, dimensions, density, etc • What are its properties? à Types of Properties Chemical & Physical Properties Quantitative & Qualitative Properties These properties are not mutually exclusive, i.e. they can overlap. For instance, a physical property can also be a qualitative property. Chemical Properties A characteristic is considered a chemical property if it describes the ability to react with another substance and form one or more new substances. Example - Iron rusts. This is a chemical property, as iron has the potential to change into a new substance (rust). Physical Properties A characteristic is considered a physical property if it can be observed and/or measured without a new substance being formed. • Example - Freezing point of water. When water changes state, a new substance ISN’T created. It’s still H2O at the molecular level. Physical and Chemical Properties of Gold Property For Gold State at room temperature Solid Colour Yellow Density 19.3 g/mL Melting point 693 ºC Electrical conductivity Good Reactivity to acid None Dissolves in water No Physical Properties Chemical Properties Qualitative vs. Quantitative Properties Subgroups of physical properties 1) Qualitative properties are descriptive properties. Example - The car is red. 2) Quantitative properties are based on a number or measurement. Example – It is 35°C outside. Common Physical Properties • Viscosity • Melting/Freezing Point • Boiling Point • Solubility • Density • Hardness • Color • Conductivity • Odor • State • Texture • Malleability Common Chemical Properties • Reaction with acid • Reaction with another substance • Combustibility (reaction with oxygen) • Ability to rust Combustion Check Your Understanding Identify the type(s) of property(ies) for the following: 1. Food rots. 2. An acid corrodes metal. 3. The weight of a gallon of oil is 7.5 pounds. Check Your Understanding Food rots • This is a chemical property, as a new substance is formed Check Your Understanding An acid corrodes metal • This is a chemical property as the acid and metal are destroyed in observing this property The chemical equation for the reaction of iron metal with sulphuric acid The international pictogram for corrosive chemicals. Check Your Understanding The weight of a gallon of oil is 7.5 pounds. • This is a physical property as the oil is not changed in making the observation • It is also a quantitative property since a measurement is involved Chemical vs. Physical Change • A chemical change results in a new substance with different properties ØA change in the molecular structure • A physical change may change the appearance of a substance, but there will be NO new substance formed ØNo change in molecular structure Chemical vs. Physical Change Examples Chemical Change • Burning wood • Decomposing water Ø(H2O à H2 + O2) • Iron rusting Physical Change • Sawing wood • Freezing water • Cleaning rust with steel wool Chemical Change Clues 1. 2. 3. 4. 5. Change in Temperature Change in Color Noticeable Odor (after reaction has begun) Formation of a Precipitate Formation of Bubbles Also, difficulty in reversing a change hints at a chemical change. Keep in mind these are only clues that a chemical change may have taken place. Proof still depends on a new substance being formed with new properties. Energy Energy is not matter; it has no mass and takes up no volume. It is the ability to do work, and comes in many different forms, including: • Heat • Mechanical – motion, position • Electrical • Sound • Chemical • Nuclear • Electromagnetic 3