Safety-Scale Sensitivity


For every lab
Wear goggle until Mr. Leeds says you can take them off
Report all accidents to Mr. Leeds immediately
Use common sense
In case of emergency
Call nurse : 2828
Safety equipment in classroom
Fire extinguisher
Fire blanket
Eye wash/Shower
Never taste chemicals
Always waft liquids
Avoid touching chemicals
Always wash hands with soap and water after lab
If chemicals touch skin flush skin with water for one minute AND notify Mr. Leeds
Hot glass and cold glass look the same
Never use chipped or broke glass
tell MR. Leeds and dispose of broken glass in proper trash can
Never use force to remove or insert glass
Alcohol Burners
Roll up sleeves put long hair up in a BUN
Never walk way from lit burner
Never point the open end of hot test tube at someone
Do not look down into a test tube/beaker while being heated
Make sure burner is capped and flame is out when done
End of experiment
Make certain that burner is out if one is used
Keep goggles on until Mr. Leeds says to put them away

Post Lab Reaction in a Bag

red liquid: phenol red
  • used as PH indicator
  • below 7 turns yellow
  • above 8 turns pink
PH Scale
  • measures acidity
  • goes from 0-14
  • acid neutral alkaline
  • lemon juice 1.5
  • Tums 10
  • Calcium Chloride
  • acidic
  • hydro tropic: attracted to water
  • uses: canned veggies,electrolytes in sports drinks, flavors (pickles,salty)
  • Sodium Bicarbonate (baking soda)
    • non acidic
    • uses: baking,laundry detergent, toothpaste

Scholar Reaction In The Bag Inquiry Demonstration and Lab Activity

Post Lab Heating Baking Soda

Gas comes from the baking soda. Condensation forms at the top of the test tube. The experiments performs a mini water cycle.
If both tubes don't look the same something is different.
Control factors: same type tea, same amount of baking soda, same amount of tea, same stirring time, same sized test tubes.
  1. control group: unheated
  2. experimental group: heated
  3. indicator: tea (shows heated baking soda has changed)
  4. variable: something you try to measure
  5. independent: causes a change in development. Our lab was temperature.
  6. dependent: color of the tea
Experimental Errors
hole in tubing- wont see the bottle fill with gas
rubber stopper- not snug you won't see the any gas be produced
stirring rod not cleaned before you begin- contamination
Extra Question
Is the amount of condensation that forms at the top of the heated test tube more or less than the amount of baking soda being heated?
ANSWER: Less b/c the condensation comes from the baking soda it can't produce more than itself.
Box Questions
  1. When baking soda is heated it releases a gas which helps the dough/batter to rise.

Lab 1.1 Heating Baking Soda

Volume 1.2

unit of measure: cm cubed (cubic centimeters)
volume: L*W*H
standard unit of length: meter (m)
1 centimeter: 0.1 m cen:100
unit cube: a small cube w/ one cm on each edge
Volume of Liquids
*Always check the intervals or scale* (use graduated cylinder to measure volume)
units= millimeters (mL) or cm cubed
Box Questions
3. 50 cm cubed
4. A has a greater width or height
5. 7cm cubed
6. (a) 8 cubes (b) 27 cm cubed
7. The rectangle (25)(16)(15)
8. As it gets higher it expands out and the depth decreases

Reading scales 1.3

Single Pan Balance
  1. Always check that pan is clean and dry
  2. Always "zero" balance before EACH massing
  • push all riders to zero (left)
  • use adjust
Box Questions
9.(a) 1.2, 3.8
(b) 1.65, 2.50, 4.50
(c) So it can be more accurate.
10. (a) 0.1 cm cubed
(b) 1.30 cm cubed
11.(a) 4.0 cm cubed
(b) 1.30 cm cubed
12. 12: 11.5-12.1 12.0: 11.95-12.04 12.00 11.995-12.004
13. Narrow and tall, more depth and easier to read.

First test review

Control group: unheated baking soda
hydrotropic: attracted to water
Control factor: same type of tea
pH scale: measures acidity
cm cubed: unit of measure for length
indicator: tea
volume: amount of space something occupies
experimental group: heated baking soda
meniscus: read at the bottom for volume to determine
mechanical pencil: not as cool as a wooden one
The red liquid known as phenol red is used as a pH indicator.
It was observed that mixing substance A with a liquid gave off heat, also known as an exothermic reaction.
It was observed that mixing substance B with a liquid made the mixture feel cold, also known as an endothermic reaction.
During the experiment a lab group has a tiny hole in their zip-lock bag. How will this affect their understanding of the lab?
The group will not know that a gas is being produced.
Based on your observations and understanding of the lab, explain why baking soda is used in cooking?
Baking soda helps the batter or dough rise. It creates a gas when it is heated.
Why is the tea used in the experiment? Discuss the specific results of its use in the lab.
The tea is used to see if the baking soda is any different after being heated. The heated baking soda made the tea cloudy and there were small chunks at the bottom. The unheated baking soda did not dissolve and it stayed at the bottom.
A lab group is unaware that there is a hole in the rubber tubing. How will this impact their understanding of the lab?
The group will not see any gas being produced and they will see that the water in the bottle doesn't decrease.
The first thing you should do when working with a balance is to clean the pan.
The formula for calculating the volume of a solid object is (L)(W)(H).
One meter is the equivalent of 100 cm.
Sodium Bicarbonate is the chemical name for baking soda.
FALSE : If the pan on your balance is dirty it is okay to switch it with another balance.
TRUE : 1cm cubed is equal to 1 mL.
FALSE : A unit cube is equal to 10 cm cubed.
NOTES: make sure to read cylinders correctly, use the right labels, and be as specific as possible (rounding to the hundredths or thousandths).

1.6 Mass Notes

Beqa: ancient standard mass used in Egypt.
Earliest balance found in Egypt ( about 7,000 years old)
mass: standard unit grams (g)
1 kilogram (kg) = 1,000 g
1 kg = 2.2 pounds (lbs)
18. B
19. a count, mass (MEASUREMENTS)
b count
c mass
d count
e volume
f mass, volume
g count
h volume
20. All solids are measured by mass ex: meat, veggies, deli meat, fish
All liquids are measured by volume ex: water, soda, olive oil, ice cream, vinegar
21. 55 g
22. Its easier to use a single pan balance.

1.8 Sensitivity of Balance Lab Chart

to find the sensitivity of a balance = change in mass over number of yes's
the ending mass - initial mass of object = change in mass
EXPERIMENTAL ERRORS: The 20X20 box might have graphite on it, which would add mass.
Not proper mass of paper cubes.
23. find the sensitivity of balance : 0.01g SHOW ALL WORK ON TESTS
26. She could find the average which would be 21.4183 grams.
27a You would want to find the range.
b No, they are all in the sensitivity of the balance (0.015g).
c Find the average.

1.8 Post Lab

mass of penny 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 copper penny has sold for $82,500

Sensitivy of Balance

The lightest mass that you can expect the balance to detect.
plus or minus the margin of error when you mass something
Our Sensitivity
0.01 - 0.02
REVIEW pg. 24-25
29 There would be no difference.
30a 130 cubes (L)(W)(H) = 5X4X6.5
b 124.6 cubes 5X4X6.23
31 24 cubes
34 Fuel oil and gas are liquids so it is much easier to sell by volume. Too many problems with weight. Coal by mass so you do not pay for airspace.
*Chart look in notebook*

36a 1,000 cm cubed (10)(10)(10)

b 2.7(1,000) = 2,700 grams

c 1.0(2.0)(250) (50)(19) = 950 grams