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 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 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 cm 3 or milliliters. Solid volumes may be calculated with formulas or by water displacement Common units are cm 3 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 cm 3 If its mass is 90 grams, what is its density? 2cm x 5cm x 3cm = 30cm 3 90g ÷ 30cm3 = 3g/cm 3
Let’s Try Some More Density Problems 1) If the mass of a rock is 500g and its volume is 25cm 3, what is its density? 2) If the density of a liquid is 1.2 g/ml, and its volume is 10ml, what is its mass? 3) If Bob’s mass is 80kg and his density is 1.6kg/l, what is his volume?
Answers: D = M ÷ V 1) 500g ÷ 25cm 3 = 20g/cm 3 2) 1.2g/ml x 10ml = 12g 3) 80kg ÷ 1.6kg/l = 50L M DV
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.