IPS Test 1
Lab Safety - The Sensitivity of Balance Lab
For Every Lab
Report ALL accidents/spills to Mr. Leeds immediately
Try your best to use common sense
Safety Equipment in Classroom
- Fire Extinguisher
- Fire Blanket
- Eye Wash/Shower
Emergencies: nurse extension: 2828
Always WAFT liquids to detect odor
NEVER WAFT SOLIDS/POWDERS
Avoid touching chemicals
Always wash hands with soap and water after lab
If chemicals touch skin: flush skin with water for 1 minute AND notify Mr. Leeds
Never use chipped or broken glass (tell Mr. Leeds and dispose of broken glass in proper trash)
Never use force to remove or insert glass
Never walk away from a lit burner
Never point the open end of a hot test tube at yourself or someone else
Do not look down into a test tube/beaker while it is being heated
Make sure burner is capped and flame is out when done
End of Experiment
Make certain that burner is out if one was used
Keep goggles on (over eyes) until Mr. Leeds says to put the away
Reaction in a Bag
- Used as a pH indicator
- Below 7 turns yellow
- Above 8 turns pink
- Measures acidity
- Goes from 0-14
- 0-7-14/Acid Neutral Alkaline
- Lemon Juice - 1.5
- Tums 10
- Hydrotropic - absorbs water
- Canned vegetables - keeps from getting mushy
- Electrolyte in sports drinks and to flavor pickles
- Hot acidic
- Tooth paste
- Laundry uses
Heating Baking Soda
- Indicator: tea (shows that the heated test tube is not baking soda)
- Control Group: unheated
- Experimental Group: heated
- Variable: a category you try to measure
- Dependant Variable: tea color
- Independant Variable: causes a change in the dependent variable - temperature (heat)
- Control Factors: same type of tea, same amount of baking soda, dame amount of tea, and same size tube
Box Questions p. 5
- Why do you think baking soda is used in baking?
- When it is heated, it releases a gas and it helps the batter rise.
Volume of Liquids
Always check the intervals or scale
Units: millimeters (mL) or cm2
Box Questions p. 8
4. Rectangular box A has greater volume than rectangular box B but the length of box A is less than the length of box A is less than the length of box B. How is this possible?
- Box A is wider than box B
5. Adding a stone to a graduated cylinder containing 25.0cm3 of water raises the water level in the cylinder to the 32.0cm3 mark. What is the volume of the stone?
6. A student has a large number of cubes that measure 1cm along each edge.
a) How many cubes will be needed to build a cube that measure 2cm along each edge?
b) How many cubes will be needed to build a cube that measures 3cm along each edge?
c) What is the volume, in cm3, of each of the cubes in a and b?
- 8cm3 and 27cm3
7. One rectangular box is 30cm long, 15cm wide, and 10cm deep. A second rectangular box is 25cm long, 16cm wide, and 15cm deeps. Which box has larger volume?
- Second box
8. Figure A shows a cone-shaped graduate used for measuring the volume of liquids. Why are the divisions not equally spaced?
- As the surface increases, the depth decreases
Single Pan Balance Notes
How to Balance
- Check pan is clean and dry
- Always "zero" balance before massing
- Push all the riser to zero (left)
- Use adjustment knob if needed
3. NEVER switch pans
4. Pick up balance by red bar only
5. Don't zero balance when done
Box Questions p. 11
a) Estimate the positions of arrows I and II in Figure B(a) to the nearest 0.1cm.
- 1.3 - 3.7
b) Estimate the positions of arrows III, IV, and V in Figure B(b) to the nearest 0.01cm.
- 1.64 - 2.51 - 4.50
c) Why should you report the positions of the arrows in part (b) to the nearest 0.01 cm and not to the nearest 0.1cm?
- Because it will be more accurate
10. What part of a cubic centimeter do the smallest divisions on each of the graduated cylinders in Figure C represent?
- 0.1 - 0.2
11. What is the level of the liquid in Figure D(a) to the nearest half division? What is the level in Figure D(b) to the nearest half division?
12. Three students reported the length of a pencil to be 12cm, 12.0cm, and 12.00cm. Do all three readings reading contain the same information
- 12: 11.5-12.4
- 12.0: 11.95-12.04
- 12.00: 11.995-12.004
13. What advantage is there making graduated cylinders narrow and tall rather than short and wide?
- It would be easier to read the measurement because the lines are further apart because there's more depth due lack of surface.
1.4 Beach Sand Lab
How to Fill in the Table - Find Volume of Sand
Air Space = Dry Sand - Sand Alone
Fraction of Sand that is Air = Air Space/Dry Sand
1.6 Mass Notes
- earliest balance found in Egypt (approximately 7,000 old)
Mass: Standard Unit - grams (g)
- 1 kilogram (kg) - 1000g
- 1 kilogram - 2.2 pounds
1.8 The Sensitivity of Balance
How to Find the Sensitivity of Balance
Sensitivity = Change in Mass/Number of Yes's
After 1982: 2.5% copper, 97.5% zinc
- made of steel and zinc
- copper was needed for shell casing (bullets)
- a 1943 penny penny has sold for $82,500