1. Physical versus Chemical Properties
Unit II - Part 1
The study of matter

2. Reviewing MATTER Matter: anything that has mass and takes up space
Mass – the amount of matter in something
Volume – the amount of space something occupies
Which of the following is matter?
A car?
A box?
You?

3. What is a property?
Property: a characteristic of a substance that can be observed

4. Physical Property
Physical property: a property that can be observed without changing the identity of the substance.
Examples:
luster
malleability: the ability to be hammered into a thin sheet
ductility: the ability to be stretched into a wire
melting point
boiling point
density
solubility
specific heat

5. Density Pre-Question
Which of the following object do you think will float in water?

6. Density Density is the amount of mass per unit of volume.
Density can be used to identify a substance.
The density of water is 1.0g/mL

7. Density Discovery Proposed Questions:
What do floating objects have in common?
What do sinking objects have in common?
- We will find out using gizmo.

8. How does liquid density affect whether objects float or sink?
Let’s find out through gizmo.
Answer:
If the density of the liquid increases the buoyancy of objects increase.
Buoyancy: The ability of an object to float.

9. How can you predict whether an object will float or not?
Calculations:
D = m/V = g/mL = g/cm3
Ex: A cube has a mass of 2.8 g and occupies a volume of 3.67 ml. Would this object float or sink in water?
Mass = 2.8 g Volume = 3.67 mL
D = 2.8g/3.67 mL= 0.76 g/mL
This object would float in water because its density is less than water (1.0 g/mL).

10. Let’s practice density!!!
NCDPI Practice

11. Solubility
What happens when you stir a spoonful of sugar into hot water?
Solubility: The ability of a substance to dissolve in a liquid.
Three Parts
Solute Solvent = Solution
(Kool-Aid Mix) (Water) (Kool-Aid)

12. Why don’t some substances mix?
Make a list of substances that don’t mix:
Oil and water
Gasoline and water
Why? Because they don’t like each other? No
Polarity:
Polar molecules mix with other polar molecules.
Non-polar molecules don’t mix with polar molecules.
“Like Dissolves Like”

13. How does temperature of the solvent affect solubility?
What is your opinion? Let’s find the answer using our Gizmo.

14. Chemical Properties
Chemical property: a property that can only be observed by changing the identity of the substance
Examples:
flammability
ability to rust
reactivity with vinegar

15. More Density Calculations
Ex: A liquid has a mass of 25.6 g and a volume of 31.6 mL. Use the table below to identify the substance.
M=25.6 g V=31.6 mL
D = 25.6 g/31.6 mL
D= 0.81 g/mL
The substance is ethanol.