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Properties of Matter. Physical Properties, Phases of Matter, Chemical Properties. General (Physical) Properties. Physical properties may be observed without changing the nature of the matter. Boiling point is a physical property
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Properties of Matter Physical Properties, Phases of Matter, Chemical Properties
General (Physical) Properties • Physical properties may be observed without changing the nature of the matter. • Boiling point is a physical property • When a liquid boils, the vapor may be condensed to get the liquid back • The liquid is still the same substance
What are some Physical Properties? • Properties you can see, such as color, shape, hardness, and texture • Properties that are easily measured, such as mass, volume, density, melting point, boiling point • Note! Freezing and melting point are the same temperature! • Density = Mass ÷ Volume • Is the ability to be attracted to a magnet a physical property?
How do we measure mass and volume? • Mass is measured on a balance or scale. Common units are grams, milligrams, and kilograms • Liquid volume is measured with a graduated cylinder. Common units are liters and milliliters • Solid volumes may be calculated with formulas or by water displacement Common units are cm3 or milliliters.
Finding Volume by Water Displacement • A wooden block raises the level of the liquid in the graduated cylinder from 150ml to 180ml. What is the volume of the block? • 180ml – 150ml = 30ml
M D I V • If the density of the block is 300g/ml, what is its mass? (remember, its volume was 30ml) • M 300g/ml I 30ml • 9000g
Measuring Volume with a Formula • A wood block as in the last example has sides that are 2cm wide, 5cm long, and 3cm high. What is the volume of the block? • Use the formula l x w x h • The answer will be in cm3 • If its mass is 90 grams, what is its density? • 2cm x 5cm x 3cm = 30cm3 90g ÷ 30cm3 = 3g/cm3
Let’s Try Some More Density Problems 1) If the mass of a rock is 500g and its volume is 25cm3, what is its density? • If the density of a liquid is 1.2 g/ml, and its volume is 10ml, what is its mass? • If Bob’s mass is 80kg and his density is 1.6kg/l, what is his volume?
Answers: D = M ÷ V M • 1) 500g ÷ 25cm3 = 20g/cm3 • 2) 1.2g/ml x 10ml = 12g • 3) 80kg ÷ 1.6kg/l = 50L D V
WEIGHT • Weight is the pull of gravity on mass. • Weight changes in response to gravitational pull. • A person’s mass will remain the same on the earth or on the moon, but she will only weigh 1/6 as much on the moon.
PHASES OF MATTER • The most common phases of matter are solid, liquid, and gas • Plasma is a high energy phase found in stars • When a substance changes phase, energy (heat) is lost or gained, but temperature remains the same.
The northern lights are caused by plasma streams from the sun hitting our atmosphere. This causes electrons in atmospheric gases to be excited to a higher energy level, And when they drop back down, a photon of light is emitted.
Types of Phase Changes • Solid to liquid: Melting • Liquid to gas: Vaporization • Gas to liquid: Condensation • Liquid to solid: Freezing • Solid to gas: Sublimation
Chemical Properties and Changes • Chemical properties describe a substances’ ability to change into a different substance. A chemical change is the process by which the substance changes.
Examples of Chemical Properties • Flammability • Ability to support burning • Ability to combine with other chemicals in a chemical reaction.
Examples of Chemical Changes • Rusting • Photosynthesis • Explosions • Burning • Digestion • Baking food • Fermentation
What are indicators of a chemical change? • Gas given off • Heat absorbed or released • Light given off • Color change • Oxidation of a metal • New substances are formed