Exam Experience


Chapter 1

Lab Safety Notes

Goggles must be kept OVER YOUR EYES until Mr. Leeds says to put them away

** even if you're already finished and cleaned up

Report ALL accidents/spills to Mr. Leeds immediately

Try your best to use common sense

Nurse Extension: 2828

Safety Equipment in Room: 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 1 minute and notify Mr. Leeds


  • hot glass looks like cold glass
  • never use chipped or broken glass, tell Mr. Leeds, and dispose of it properly
  • never use force to remove or insert glass

Alcohol Burners

  • roll up sleeves, put UP long hair, NOT just pull back (or u can't 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 & materials completely
  • Make certain that burner is out if one was used
  • Keep goggles on (over eyes) until Mr. Leeds says to put them away

Lab: Reaction in a Bag

Red Liquid

Phenol Red

  • used as a Ph indicator
  • below 7 turns to yellow
  • above 8 turns to pink

Ph Score

  • measures acidity
  • goes from 0-14
  • most acidic is 0 and most alkaline is 14
  • lemon juice 1.5

2 Solids

A. Calcium Chloride (calcium+chloride)

  • Solid- mildly acidic
  • hydrotropic: attracted to water (absorbs water)
  • Uses: canned vegetables (keeps them from getting mushy), electrolytes in sports drinks, and flavors pickles (salty flavor)

B. Sodium Bicarbonate (baking soda)

  • not acidic
  • uses: baking, cat litter, toothpaste, laundry detergent

Hole in the bag- gas is not produced

Lab: Heating Baking Soda

Top- Condensation, moisture/foggy- comes from hot gas touching cooler surface at top of test tube cools back to liquid

Bottom-Baking Soda- gas comes from here

Heated and Unheated test tubes should have a color difference.

Are the two white powders the same substance? What is your evidence?

No, they are not the same because the heated test tube is a different color then the unheated test tube (that you know is baking soda).

Control Group/Factor: nonheated test tube

Experimental Group/Factor: heated test tube

Indicator: tea (showed you that heated test tube wasn't baking soda)

Variables: something you want to measure

Independent Variable: causes a change in the dependent variable; in this lab it was temperature (heat)

Dependent Variable: color of tea

Control Factors: factors/things in lab that we have control over

In this lab some were:

  • same type of tea in each test tube
  • amount of baking soda (same)
  • amount of tea (same)
  • same amount of stirring time
  • same size tube

Experimental Errors:

  • hole in tubing- would cause the bottle not to fill with gas
  • don't clean stirring rod at beginning would cause contamination
  • stopper not snug would cause a gas

Extra Questions:

Is the amount of condensation that forms at top of the heated test tube more or less than the amount of baking soda?

Less (or equal to), because condensation comes from the baking soda and the baking soda cannot produce more than itself.

Big image

1.2 Volume Notes

  • unit of measurement: cm3 (cubic centimeters)
  • volume= length x width x height
  • standard unit of length= meter (m)
  • 1 centimeter (1 cm) (centi means 100)= 0.01 meters
  • 100 cm= 1 meter

Unit cube:

  • a small cube 1cm on each edge and side
  • volume= 1 cm3

Volume of Liquids:

  • use a graduated cylinder to measure volume
  • units= millimeters (mL) or cm3
  • 1 mL= 1 cm3
  • read form bottom of meniscus

Single Pan Balance Notes

  1. check that pan is clean and dry.
  2. always "zero" balance before EACH massing 1. Push all riders to the zero (left) 2. 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 Question Answers #1-13 (no #2)

  1. It releases gas when heated, which helps dough/batter to rise (cupcakes, cookies, etc.)
  2. n/a
  3. 50 cm3
  4. If the width and/or height are greater on Box A
  5. 7 cm3
  6. A. 8, B. 27, C. 8 cm3, 27 cm3
  7. 6,000 (the second one)
  8. They are different because the shape of the graduated cylinder goes from small to big (cone-shaped); as the surface increases, the depth decreases.
  9. A. I: 1.2 cm, II: 3.7 cm; no B. yes, III- 1.64 cm, IV- 2.51 cm V, 4.50 cm C. more accurate
  10. A. 0.1 cm3 B. 0.2 cm3
  11. A. 4 cm3 B. 1.30 cm3
  12. 12 cm: 11.5-12.4 were rounded up/down 12.0 cm- 11.95-12.40 were rounded up/down 12.00- 11.995- 12.004 were rounded up/down
  13. Liners are further apart because there is less surface= more depth/height which makes it easier to read

Measuring Volume by Displacing Water

Experimental Errors

  • sand sticks to side of wet cylinder- volume of sand and water would be too low
  • pour water into sand- water sits on top of sand bc the air spaces don't allow water to filter down

Big image

What is the volume of water that fills the air spaces in the dry sand?

29 cm3

What is the volume of the water that does not fill the air spaces in the sand?

17 cm3

BQ 14, 16, 17-20

14. C- less than 100

16. Find liquid that sugar does not dissolve in bc it dissolves in water (oil). Fill grad. cylinder with liquid and record volume. Pour sugar into grad. cyl. Record new volume and calculate.

17. Find the volume of a weight (rock, etc). Use displacement of water method with weight and cork. Subtract volume of weight. Calculate volume of cork.

18. B- the masses of the objects are the same

19. a. count or mass b. count c. mass measurement d. count e.volume f. count or mass g. count h.volume

20. Mass- beef, bread, fruits, veggies, fish, candy, rice

Volume- milk, butter, juice, soda, water, oil, soup

1.6 Mass Notes

  • Beqa- ancient standard mass used in Egypt
  • Earliest balance found in Egypt (approx 7,000 years old)
  • Mass- standard unit- grams- 1 kg= 2.2 lbs

Sensitivity of a Balance Lab

∆M This formula= sensitivity of balance

# of yes's

Sensitivity of Balance- the lightest mass that you can expect the balance to detect or the + or - margin of error when massing something

Sensitivity of Balance- 0.02

BQ 23, 26, 27, 29, 30, 31, 34, 35, 36, 37

29. Volume would be the same; no difference

30. a. 130 cubes b. 124.6 cubes

31. 24; you could count how many 3x4x2 cubes were needed or you could calculate the area and subtract it by the amount of cubes shown

34. fuel + gas (liquids): by volume because more efficient (less steps)

coal (solid): mass because there is air space within the coal. Don't want to pay for air

35. Mass- chuck, tomato sauce Volume- green pepper, salt oil Other- onion, bread, pinch pepper, steak sauce, oregano

36. A) 1,000 CM3 B) 2700 g

37. A) 950 g

Chapter 2

The Mass of Dissolved Salt

Exp Errors:

-not drying off the cap- water in Mi not there for Mf

-remove cap before Mf- spillage/leakage

-not shaking long enough- not dissolved

-cap not on tightly- spillage/leakage

-spill salt when pouring into bottle


1. C: 3,5 IC: 1,2,4

2. You will get the wrong ∆M.

3. No, because it is there in both the Mi+Mf.

4. -Remove cap+allow water to evaporate -mass is the same- salt cannot evaporate with the water

5. no, below the balance sensitivity

6. A) +1 kg, -2 kg B) +4˚C, -5˚C

8. yes, yes, yes, yes, no, no

9. a. -0.01- -0.03 b. 5,7,10,14

10. A) 0.02 B) 3,4,6,8,9,16,17,18,19 C) 2,20

11. a. reference to notebook b. it is empty because no one received 0.01 c. no because it is consider the sensitivity of balance (interval is too small 0.01)

Ice Ice Baby or Ice and Water Lab

Condensation on bottle comes from warm water vapor in the air (humidity). When it touches cool surface of bottle, it turns from gas to liquid.

Exp Errors:

-not wiping off condensation after Mi- gain mass

-cap not sealed (hole), water eval- loses mass

-ice not fully melted

-bottle is wet during Mi- lose mass

-shaking bottle- could lose mass

Mass of Copper and Sulfur

yellow smoke- water in sulfur turns to vapor (gas) and rises in test tube

when it cools- sulfur bonds with copper forms copper sulphide

Exp Errors:

-sulfur sticks to side of test tube- doesn't react

-hole in rubber sheet or sheet is not on test- gas

-clean pan btw Mi + Mf

If we used stopper, pressure would build up in test tube.

Reference to chart in lab

Mass of a Gas

Look at Data table

Exp Errors:

  • touch tablet after Mi- decrease in mass
  • cap is wet during Mi- lose mass
  • water in the pan during Mi- lose mass
  • cap not on tight or not on quick enough- lose mass bc of evaporation


Antacid for acid reflex and pain reliever



-citric acid (flavor)

-sodium bicarbonate (produces gas)

Closed System: a space where nothing can enter or leave

Law of Conservation of Mass

In a closed system mass will remain consistent regardless of the actions of the processes inside the closed system.

Basically: as long as its closed system, mass will stay the same.

If labs are done right, everyone should get -0.02 to +0.02.

BQ 17, 19-23

17. No, because the beaker is an open system. They lose mass to evaporation.

19. Yes, if there is gravity; no if there isn't gravity

20. Yes, if you're on Earth; no if you are on a different planet

21. -the water could evaporate, -condensation could form on the inside of bottle

22. Should stay constant as long as it is a closed surface

23. Mass should stay the same bc baking soda gas can't escape

Chapter 3

Chapter 3 Multiple Choice

In order to calculate density we found both the mass and volume of the liquid in the graduated cylinder because it is the most accurate method and we didn't have to transfer liquid.

During the Density of a Gas lab the rubber tubing is incorrectly inserted near the bottom the bottle, this will cause less gas to collect in the bottle.


Reference to graphs in notebooks

Reference to calculations in notebooks

Characteristic Properties

property of an object: doesn't tell you what the substance is made out of

property of a substance: this helps you to identify what the object is made


1. object, object, object, substance, object

2. object, object, object, substance

3. object, substance, object

Mass and Volume


- using same long cylinder 2x

- cylinder is wet when massed- + mass

-water splashes out of cal during displacement- - volume

Objects that are made of the same substance that have the same volume will have the same mass.

Ex: long aluminum cyl and small aluminum cal

The mass of an object will double if its volume doubles.

Objects that have the same volume but are made of different substances will NOT have the same mass Ex: brass + aluminum cylinders

Density of a Solid

Histogram shows that Cube 1 and Slab are same substance. Cube 2 are different substance.

Why do lab groups get different density calculations for their rocks?

The rock is formed by many substances being compressed together. Diff substances- diff. densities


-measure the same side twice

-water splashes out of grad. cyl.

-find v. of rocks before mass- m+= d+

-paint chips off objects- mass -

BQ 15-17

15. Clean and zero balance, calculate mass, measure dimensions, m/v=d

16. no, because it doesn't depend on size or substance, the density stays the same. depens on substance

17. yes, because they are the same mass and substance so their density has to be same

Density of Liquid


-dont rinse out btw substances- substances mix= change in density

-cylinder is not re-massed empty

-outside of cylinder is wet during mass empty- adds mass, not going to be there later in lab

Substance: magnesium sulfate (Epsom salt) dissolved in water)

Density of a Gas


-make sure hand seals bottle or too big of air bubble- +V= -D

-touch tablet or forget to put on foil after Mi- Mf gets too small= M+=D+

-spill water finding volume of bottle- d-