IPS Test 1

Lab Safety - The Sensitivity of Balance Lab

Lab Safety

For Every Lab

Goggles must be kept OVER YOU EYES until Mr. Leeds says to put them away (even if you are already finished and cleaned up)

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

Chemicals

Never taste chemicals (even if they look yummy)

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

Glass

Hot glass and cold glass look the same

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

Alcohol Burners

Roll up sleeves, put UP long hair, NOT just pull back (or you cannot do lab)

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

CLEAN-UP AREA AND MATERIALS COMPLETELY (or you LOSE points)

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

Red Liquid

Phenol Red

  • Used as a pH indicator
  • Below 7 turns yellow
  • Above 8 turns pink


pH Scale

  • Measures acidity
  • Goes from 0-14
  • 0-7-14/Acid Neutral Alkaline
  • Lemon Juice - 1.5
  • Tums 10

Solid A

Calcium Chloride

  • Acidic
  • Hydrotropic - absorbs water

Uses:

  • Canned vegetables - keeps from getting mushy
  • Electrolyte in sports drinks and to flavor pickles

Solid B

Sodium Bicarbonate (Baking Soda)
  • Hot acidic

Uses:

  • Baking
  • Tooth paste
  • Laundry uses


Heating Baking Soda

Part A

The gas leaving the tube comes from the baking soda.


The condensation comes from the baking soda, when the hot gas touches cooler top part of the test tube and turns back to a liquid.

Part B

  • 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

  1. 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 Notes

Volume

Unit of measurement: cm3 (cubic centimeters)

Volume: length x width x height (a x b x c)

Standard unit of length: meter (m)

1 centimeter (1cm) = 0.01 m - 100 cm = 1 m

Unit cube - a small cube which measures 1cm on each edge


Volume of Liquids

Use a graduated cylinder to measure volume

Always check the intervals or scale

Units: millimeters (mL) or cm2

1mL=1cm2

Box Questions p. 8

3. How many cubic centimeters of water are required to fill a graduated cylinder to the 50.0mL mark?
  • 50cm3


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?

  • 7cm3


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?

  • 8

b) How many cubes will be needed to build a cube that measures 3cm along each edge?

  • 27

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

  1. Check pan is clean and dry
  2. 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

9. The scale in Figure B is in centimeters

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?

a) 4.0cm

b) 1.30cm


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

Sand Alone = Sand and Water - Water


Air Space = Dry Sand - Sand Alone


Fraction of Sand that is Air = Air Space/Dry Sand

1.6 Mass Notes

Beqa - ancient standard mass used in Egypt
  • 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

Change in Mass = Original Mass - New Mass


Sensitivity = Change in Mass/Number of Yes's

Penny Notes

Before 1982: 95% copper, 5% zinc

After 1982: 2.5% copper, 97.5% zinc


1943:

  • made of steel and zinc
  • copper was needed for shell casing (bullets)
  • a 1943 penny penny has sold for $82,500