Now that the term is drawing to a close, it's time to review and prepare for your exams.
- Lab Exam: Friday, Jan. 17
Here's the first page of the exam with instructions and rules: Lab Exam Page 1
Here are some review notes we discussed in class...
Format
- One full period (75 minutes).
- Complete 5 activities.
- Work individually.
- Bring only a pencil, eraser and calculator.
- Worth 10% of your final mark.
REVIEW
Previous Labs
- Density
- Physical and Chemical Change
- Charging Objects
- Building Circuits
- Ohm's Law
Dry Labs (Space and Ecology)
- You will be provided with data.
- You will do an analysis by answering questions.
Review Density
Definition: mass divided by volume.
D = m / V m = D x V V = m / D
How did you measure density in your lab?
We measured D for water.
- graduated cylinder measures V in mL.
- scale measures m in g.
Example:
A block of wood has volume 36 cm^3 an weighs 22 g. What is the density? Will it float?
Given: V = 36 cm^3, m = 22 g
Required: D = ?
Analyze: D = m / V
Solve: D = 22 g / 36 cm^3
= 0.61 g/cm^3
Statement: The Density is 0.61 g/cm^3, it will float.
**The Density of water is 1 g/cm^3.
Example:
Mercury (the element, not the planet) has a density of 7.6 g/cm^3. If you want to measure out 1 kg of it, how big of a container do you need?
Need volume, V. 1 cm^3 = 1 mL
1 kg = 1000 g
V = m / D
V = (1000 g) / (7.6 g/cm^3)
= 131.578 mL
= 130 mL
Review Significant Digits
- Any non-zero is significant
2913 four sig. digs.
2900 two sig. digs.
- Zeroes in-between digs are significant.
2014 four sig. digs.
With a decimal…
- Zeroes on the left are NOT significant
0.0025 two sig. digs.
- Zeroes on the right ARE significant
0.250 three sig. digs.
100.0 four sig digs.
HOMEWORK
Read and Review the following. This will help you prepare for the dry labs.
- P. 43-44 (Food Webs),
- P. 45 (Ecological Pyramid),
- P. 111 #13 (Changing food web)
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