Properties of Matter

1. Properties of Matter

2. General (Physical) Properties • Physical properties may be observed without changing the nature of the matter.

3. What are Physical Properties? • Properties you can see • color, shape, hardness, and texture • Properties that are easily measured • mass, volume, density, melting point, boiling point

4. Examples of Physical Properties • boiling point • The liquid is still the same substance • After a liquid boils, the vapor may be condensed to get the liquid back • Freezing and melting happen at the same temperature. freezing point = melting point

5. What is a fluid? • Fluids: • includes liquids and gases • can flow and take shape of their container

6. Properties of fluids • viscosity – resistance to flow • Example: water is less viscous than honey • depends on temperature • heating a fluid lowers viscosity; • cooling a fluid increases it’s viscosity. • Example: Warm honey flows more easily than cold honey. • buoyancy – ability of a fluid to exert an upward force on an object immersed in it.

7. Properties of solids, liquids and gases Density – mass per unit volume • depends on temperature • heating a material decreases its density; • cooling a material increases its density • remains the same regardless of how much material is present • Example: 1mL of water has the same density as a lake full of water.

8. Density • whether something sinks or floats determines • materials that are less dense will float on denser materials • Materials that are more dense sink • oil floats on water because it is less dense than water; • a helium balloon floats in air because the density of the helium in the balloon is less than the density of air in the same size balloon

9. Understanding the Densities of solids, liquids and gases

10. How to 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.

11. Finding Volume 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

12. 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 2cm x 5cm x 3cm = 30cm3

13. Let’s Try Some Density Problems • 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?

14. Calculating Density m D v

15. 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

16. 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.

17. States of Matter

18. Types of Phase Changes • Solid to liquid: melting • Liquid to gas: vaporization Example-- steam

19. More Phase Changes • Gas to liquid: condensation example -- clouds • Liquid to solid: freezing example – snow or ice • Solid to gas: sublimation example -- dry ice

20. Temperature Doesn’t Change During a Phase Change!

21. THE END