Properties of Matter

1. Properties of Matter SNC1P Mr. M. Couturier

2. Problem • Question: What physical and chemical properties should braces (used to straighten teeth) possess in order to attain its desired goal (to straighten the teeth) while not presenting a health hazard to the individual?

3. Hypothesis • Discuss with a few neighbours the question that has been presented to you and brainstorm the desired physical and chemical properties that it should possess. (5 minutes) GO!!!

4. Physical Properties • A physical property is a characteristic or description of a substance that may help to identify it. • A key concept is that when a substance undergoes a physical change, only the substance’s appearance has changed.

5. Using your senses • Although this is not recommended in a science lab, you’ve been describing physical properties using your senses: • Sight • Touch: • Taste: • Smell:

6. Describing Properties

7. The States of Matter • One way of describing a physical property is to note observe its state while at room Temperature (22°C): solid, liquid or gas. • From this property, we can deduce two other properties qualitatively (without numerical values): relative shape and volume.

8. Solids • When a substance is in its solid state, it has a definite or fixed (unchanging) shape. Its volume is also fixed. • THINK: An ice cube is placed in a glass. The ice cube does not take the shape of the glass because its shape is not changing, hence, its volume remains the same.

9. Liquids • When a substance is in its liquid state, it has an indefinite or changing shape, but its volume is fixed. • THINK: Water is poured into a glass. The water takes the shape of the glass, but it will only occupy the space which is dictated by its volume. This is why the glass can be half full or half empty.

10. Gases • When a substance is in its gaseous state, it has an indefinite or changing shape and an indefinite volume. • THINK: In a room, is there a place in the room where there is no air? No because regardless of how much air is in the room, the air will occupy the entire room; regardless of the shape of the room.

11. State – Shape - Volume

12. Hardness • Hardness is a measure of the resistance of a solid to being scratched or dented. Diamonds tend to be the used excessively for cutting other objects due to its superior hardness.

13. Malleability • Malleability is an object’s ability to be shaped into different forms (i.e. flattened, bent, etc.). Metals tend to be malleable. For example, aluminum is used at home in the form of wrapping because it can be flattened into thin sheets and it can be shaped into just about any solid object. Substances, like sulfur, which are not malleable are said to be brittle, because they shatter.

14. Ductility • Ductile objects have the ability of being pulled into long wires when in solid form. Copper is ductile because it can be made into very long copper wires.

15. Melting and Boiling • Substances are bound by Temperature limits in which their shape and volume alter as a result of their state. We refer to a melting point when a substance transforms itself from a solid to a liquid (or vice versa). We refer to a boiling point when a substance transforms itself from a liquid into a gas (or vice versa). An ice cube melts to become liquid water at 0°C and then become a gas at 100°C (and vice versa).

16. Crystallization • Crystallization is a substance’s ability to form into a crystal when in solid form. They normally form regular patterns (sometimes cubes) for example quartz, various salts, etc.

17. Solubility • Solubility is a substance’s ability to dissolve in a solvent (water). When drinking tea or coffee, some people add sugar, which dissolves into the solvent. An additional property associated with solubility is a substance’s saturation level. If you can add sugar to the coffee and it dissolves, we say that the coffee is unsaturated (meaning that it can dissolve more sugar).

18. Solubility • The point at which you can no longer add any more sugar, such that it dissolves is its saturation point. If you can add sugar to the coffee and it no longer dissolves, we say that the coffee is supersaturated.

19. Viscosity • Viscosity is an substance’s ability to flow when in its liquid form. Thick liquids are said to be viscous such as honey or maple syrup. Water would have a relatively low viscosity level.

20. Density • Density is a measure of matter per unit of space occupied expressed in g/L, kg/L, mg/mL, etc. • DENSITY = MASS . VOLUME • THINK: A standard box is filled with pillows, while another standard box is filled with books. They occupy the same space, but have completely different masses. Hence the box of books have a higher density.

21. Density • Example: A substance has a mass of 380.0g and occupies 75mL. What is its density?

22. Density • Example: A substance has a mass of 380.0g and occupies 75mL. What is its density? • DENSITY = MASS . VOLUME • Density = 380.0 g 75mL • Density ≈ 5.1g/mL

23. In summary • When water undergoes a physical change, we can still say that it is water. It can be: • warm water (heated) • solid water (frozen) • salty water (salt dissolved into water) • crystallized water (water in the form of a snowflake)

24. Chemical Properties • A chemical property describes the behaviour when a substance is introduced (or reacts) with another substance. When a chemical reaction has occurred, a new substance is produced with new physical properties.

25. Combustibility • Combustibility is a property that describes the ability of a substance to react with oxygen to produce carbon dioxide (CO2). A substance is combustible or flammable if it burns when introduced to a flame. If a substance does not burn when introduced to a flame, then it is said to be nonflammable.

26. Reaction to Acids • Scientists conduct acid tests to determine whether a substance will react to acid. By placing a drop of acid on the substance, the substance will either react by releasing bubbles of gas or not react at all.

27. Alloys • Later in the course, we will discuss the classification of elements in terms of their properties within the context of the Periodic Table of Elements. • One such classification of elements is to divide them between those that are metals and those that are non-metals.

28. Alloys • We will see that non-metals react with other non-metals and metals, but metals do NOT react with other metals. The key word here is “they will not REACT” together, but metals can be boiled into liquid form, mixed together and then allowed to cool. The cooled substance will form an alloy: a mixture of metals.

29. Alloys • Common alloys include: • Steel • Gold alloy (jewelry form) – not pure gold • Nickel alloy • Titanium alloy • Bronze

30. Common Alloys

31. Braces • Question: What physical and chemical properties should braces (used to straighten teeth) possess in order to attain its desired goal (to straighten the teeth) while not presenting a health hazard to the individual?