December 18-19

By Rodrigo Torrejon

Safety Quiz Notes

Keep Goggles over eyes and apron on at all times.

Emergency number: 2828


Never taste chemicals

Always waft liquids

Never Waft Solids or powders.

If chemicals touch skin, wash with soap and water and notify Mr. Leeds


Hot and Cold Glass look the same

Never used chipped or broken glass

Never use force to remove or insert glass


Roll up sleeves, put hair up while working with fire

Never leave burner unattended

Never point open end of a hot test tube at anyone

Do not look down a test tube while it is being heated

Make sure burner is capped when done



Keep goggles on until Mr. Leeds says to put them away.

Reaction in a Bag Lab Notes


  • Phenol Red
  • Used as a pH indicator
  • Below 7 turns yellow
  • above 8 turns pink


  • measures acidity
  • goes from 0-14
  • 0-6 is acidic
  • 7 is neutral
  • 8-14 is alkaline


  • Calcium Chloride
  • Acidic
  • hydro-topic: attracted to water (absorbs water)


  • Sodium Bicarbonate (Baking Soda)
  • not acidic


  1. a hole in the bag: you would not see that gas was produced.


  • A+liquid= exothermic reaction (hot)
  • B+liquid= endothermic reaction (cold)
  • A+B+liquid= gas

Reaction Bag


1.1 Heating Baking Soda Lab Notes


  • gas comes from baking soda, which goes through the rubber tubing, and pushes the water out of the inverted bottle.
  • condensation comes from hot gas touching the cooler surface of the top of the test tube turns back into liquid.


  • No, the heated one is different because it is not the same color as the unheated one (you know is baking soda)

Control Group: unheated test tube

Experimental Group: Heated test tube

Indicator: Tea (indicates that the heated baking soda has changed)

Variable: something that you try to measure

Independent Variable: causes a change in the dependent variable

-temperature (heat)

Dependent Variable: color of the tea

Control Factors: things that we control during the experiment

  • same type of tea
  • same amount of baking soda
  • same amount of tea
  • same stirring rod
  • same size of test tube


  • a hole in the rubber tubing and/or if your stopper is snuggly: you won't see the bottle fill with gas
  • stirring rod not clean before you begin: could contaminate


  • Less or equal because the condensation comes from the baking soda. It cannot produce more than itself.

Lab 1.1 Heating Baking Soda

1.2 Volume notes

unit of measurement: cm³ (cubic centimeters)

Volume = L x W x H (A x B x C)

Standard unit of length= meter (m)

1 centimeter = 0.01 m

100 cm = 1 m


- a small cube 1 cm on each edge

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Volume of liquids

Always check the intervals or scale of the graduated cylinder

units= milliliters (mL) or cm³

1 mL= 1 cm³

read from the bottom of the miniscus

1.3 Reading Scales

If the mark is between 4.8 and 4.9 then the answer is 4.85

If the mark is between 4.8 and 4.85 then the answer is 4.825

If the mark is on 4.8 then the answer is 4.80

Single Pan Balance

Zero the balance with the adjustment knob

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  1. When heated, baking soda causes a gas which helps dough/batter to rise (cupcakes, bread, cakes, etc.)
  2. N/a
  3. 50 cm³
  4. If A has a greater mass, but B has a greater length, how is possible? : A has a greater width and/or height.
  5. 7 cm³
  6. a is 8 cm³ and b is 27 cm³
  7. 2nd box has a greater volume
  8. The width is bigger on the top than the bottom. As the surface increases the height decreases. Vice versa
  9. it makes it more accurate
  10. (a) is 0.1 cm³, (b) is 0.2 cm³
  11. (a) is 4.0 cm³, (b) is 1.35 cm³
  12. 12 cm rounds from 11.5 cm-12.4 cm; 12.0 cm rounds from 11.95 cm- 12.04 cm; 12.00 cm rounds from 11.995 cm-12.004 cm
  13. the lines are further apart on a narrow and tall test tube because less surface=more depth and easier to read.

1.4 Measuring Volume by Displacement of Water


Volume of Dry Sand

31.0 cm3

Volume of Water

16.0 cm3

Volume of Sand and Water

35.0 cm3

Volume of Sand Alone

19.0 cm3

Volume of Air Space

12.0 cm3

Fraction of Sand that is air


% of sand that is air


Experimental Errors:

  1. sand sticks to sides of wet cylinder: volume of sand of water would be low.
  2. Pour water into sand. (water sits on top of sand because the air spaces don't allow water to filter down)

Extra questions:

Volume of dry sand (air)

- Volume of sand alone


Volume of Air

Volume of sand and water

- Volume of water


Volume of sand alone

Volume of Air


Volume of dry sand

1.6 Mass Notes

  • Beqa: ancient standard mass used in Egypt
  • Earliest Balance found in Egypt (approx 7,000 years old)
  • Mass: Standard unit is grams (g)

1 Kilogram (kg) = 1,000 g

1 kg = 2.2 pounds (lbs)

1.8 Sensitivity of a Balance

Mass of 20x20



Delta mass

____________ = Sensitivity of a Balance

number of yes's

Ending Mass (#10)

- initial mass of object


delta mass

Experimental Errors:

  1. if squares were not cut correctly: it could affect the outcome of the experiment
  2. if graphite got on the square: then mass would be altered

1.8 Post Lab

Penny Notes

Before 1982:

95% Copper

5% Zinc

After 1982:

2,5% Copper

97.5% Zinc


- made of steel and zinc

- copper was needed for shell casings (bullets)

- a 1943 copper penny has sold for $82,500!

Sensitivity of a balance: the lightest mass that you can expect the balance to detect

+- the margin of error when you mass something


Finding Mass

  1. What is the mass of an iron bar that is 2cm x 4cm x 11cm? (1cm3 of Iron has a mass of 7.8g)

2 x 4 x 11= 88 cm3

88cm3 x 7.8g= 686.4 g

Know how to do the chart.

  1. A volume of 87cm3 of dry san is added to 46cm3 of water for a total volume of 104 cm3 (convert fractions to percentages and round to the whole number)

Volume of Dry Sand

87.0 cm3

Volume of Water

46.0 cm3

Volume of Sand and Water

104.0 cm3

Volume of Sand Alone

58.0 cm3

Volume of Air Space

29.0 cm3

% of Dry sand that is sand


% of Dry sand that is air Space


  1. What is the Volume of water that fills the air spaces in the dry sand? 29cm3
  2. What is the volume of the water that does not fill the air spaces in the sand?

1 Kilogram= 2.2 lbs

Sensitivity of the Balance= -0.02 --- 0.02




Measuring rulers and reading graduated cylinders.

Pennies were not made out of copper in 1943. Instead the copper was replaced with steel. zinc was in both.

Chapter 1 Vocab

Observation- information obtained by the senses- often by direct


Inference- a conclusion based upon known observations.

Hypothesis- A proposed solution to a scientific problem.

Control Group- the group that is the standard for comparison in any


Experimental Group- the group receiving the variable being tested.

Control Factors- the variables that are held constant. They are the same

for both the control group and the experimental group.

Indicator- a substance used to show the presence of another


Volume- the amount of space something occupies. True of solids,

liquids, and gases.

Volume Displacement Technique- quick and easy way to determine

the volume of a solid or gas.

Mass- the amount of matter in a substance (true of solids, liquids, and


Meniscus- the curved portion of a liquid when in a container. Must read

the bottom of the meniscus- at eye level- for proper



Post Lab 2.1 The Mass of Dissolved Salt

4 out of 8 groups (50%) showed no change

since it is a closed circuit, there is no change.

Experimental Errors:

  • Not drying off cap: water in Mi not there for Mf
  • remove cup before Mf: spillage/leakage
  • not shaking long enough: not fully dissolved
  • cap not on tightly: spillage/leakage
  • spill salt when pouring into bottle


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Used for financial

2.4 "Ice, Ice, Baby" Lab

Closed Circuit: NO CHANGE IN MASS

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.

Experimental Errors

  • not wiping off condensation: gain mass
  • Cap off or loose: water evaporates: Loss Mass
  • Ice hasn't completely melted
  • Bottle we during Mi: Lose mass
  • Shaking bottle: Lose mass

Big image

2.5 The Mass of Copper and Sulfur

Melting point of Copper= 1.100 degrees C (2,000 F)

Melting point of Sulfur= 112 degrees C (235 F)

Yellow smoke: water in sulfur turns to vapor (gas) and rises in test tube

When it cools: sulfur bands with copper and forms Copper Sulfide.

Experimental Errors:

  • Hole in the rubber sheet: gas could escape or the sheet pops off
  • not sealed around the top

2.6 The Mass of a Gas

Experimental Errors:

  • water in the pan during the Mi: evaporates: lose mass
  • touch tablet after Mi: chalky, rubs off: loss of mass
  • Cap is not tight or on quickly: loss of mass
  • Cap wet: reaction, gas: Loss mass

Alka-Seltzer: Antacid and Pain reliever

  • Aspirin
  • Citric Acid
  • Sodium Bicarbonate: produces gas

2.7 Conservation of Mass notes

Closed System: a space where nothing can enter or leave

Law of Conservation of Mass

In a closed system, Mass will remain constant, regardless of the actions of the processes inside the closed systems.


Chapter 2 Test

  1. During the Ice and Water lab a lab group forgot to put the cap on their bottle. By the time they realized their mistake some condensation had already formed on the outside and inside of the bottle. They should:



Chapter 3 Vocab

Characteristic Properties- Properties that show differences between


Examples: density, boiling point, solubility,

melting point.

Plateau- The flat portion of a graph. Indicates no change in the

dependent variable (y-axis.)

Phase Diagram- A graph that shows the changes in state of matter for

any substance. Represents physical changes in the


Barometer- Used to measure atmospheric air pressure. Contains a

column of mercury and a metric scale in a sealed container.

Barometric Pressure- air pressure generated by the atmosphere.

Density- Mass per unit volume of any substance. Unit of measure is


3.1 Characteristic properties

Property of an object: Does not tell you what it is made out of.

Property of a substance: This helps you to identify what the object is made out of.

Example: small chunk black tar

Small: object

chunk: object

black: object

Tar: substance

3.2 Mass and Volume Lab

Cube 1 and slab had similar densities and Cube 2 is a different substance.

Experimental Errors:

  • Mix up cylinders
  • Cylinder is wet during massing-mass increase
  • water could splash out of cylinder- volume increase

3.2 Mass and Volume notes

  1. objects that are made of the same substance volume will have the same mass (regardless of shape)
  2. The Mass of a object will double if its volume doubles
  3. Objects that have the same volume but are made of different substances will NOT have the same mass.

3.3 Density

D= m divided by V

Aluminum= 2.7 g/cm3

Brass= 8.5 g/cm3

3.5 The Density of a Solid Lab

Histogram shows that cube 1 and slab are most likely same substance

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

- All have different because the rock is formed by many substances being compressed together.

Experimental Errors:

  • water splashes out of graduated cylinder: Loss in volume
  • paint chipped off object: loss in mass
  • measure same side twice
  • Find V. of rock before mass- gain in mass; which means greater density.

3.6 The Density of a liquid

Experimental Errors:

  • don't re-mass cylinder (empty)
  • water on outside of cylinder (empty)
  • don't rinse out cylinder between substances.

Liquid A-Magnesium Sulfate

Liquid B- water

3.7 The Density of a Gas

Gas is carbon dioxide


M divided by V equals density


Zack's friend Two Chainz necklace contains 0.8 kg of Platinum. If the density of Platinum is 21.4 g/cm3, what is the volume of his necklace.

0.8 kg= 800 g

21.4= 800 divided by V


37.4 cm3

Scientific Notation:

  • Mi= 32.64g
  • Mf= 31.86g
  • Volume of Gas= 202



- 32.64



-------- = 0.0038613 g/cm3 = 3.9 x 10 (to the negative cubed)

202 cm3

  1. 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.
  2. During the Density of a Gas lab the rubber tubing is incorrectly inserted near the bottom (mouth) of the bottle. This will cause: less gas collected in the bottle
  3. If the error in #3 is made it will have the following affect: volume decrease, density increase

Carbon dioxide= gas released by sodium bicarbonate (alka-seltzer)

If the density of a gas lab a student forgets to include the foil for the Mf, the result is: mass of gas decreases, density decreases.

Magnesium Sulfate