EXAM STUDY GUIDE

By: Grace Luciano

Part 1: Safety

For Every Lab
  • Goggles must be kept over your 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


In Case Of Emergency

  • The Nurse's extension is: 2828


Safety Equipment in Classroom

  • Fire Extinguisher- To put out a fire.
  • Fire blanket- If a part of your body is on fire you wrap that body part in the blanket.
  • Eye wash/shower- If chemicals or other substances have gotten on you.


Chemicals

  • Always WAFT liquids to detect odor
  • Never taste chemicals
  • Avoid touching chemicals
  • Never waft solids/powders
  • If chemicals touch skin flush skin with water for 1 minute AND notify Mr. Leeds
  • Always wash hands with soap and water


Glass

  • Hot glass and cold glass look the same
  • Never force to remove or insert glass
  • Never use chipped or broken glass

-Tell Mr. Leeds and dispose of broken glass in proper trash


Alcohol Burners

  • Roll up sleeves, put UP long hair (in a secure pony tail or bun without any loose strands)
  • Never walk away from a lit burner
  • Never point the open end of a hot test tube at yourself or someone else
  • Make sure burner is capped and flame is out (the flame should go out because fire needs oxygen)
  • Do not look down into a test tube/beaker while it is being heated


End of Experiment

  • Clean up area and materials completely! (or points will be taken off)
  • Make certain that burner is out if one was used
  • Keep goggles on and over eyes until Mr.Leeds says to take them off




PART 2: Heating Baking Soda- post lab

Blue Dot Questions
  • What do you observe at the bottom of the test tube?

The glass turned a little brown from being heated.


  • What do you observe near the top of the test tube?

At the top of the test tube condensation is forming and droplets of water appear.


  • What do you observe in the inverted bottle?

The water is decreasing because the air is taking place of the water.


  • Where do you think the gas came from?

I think the gas came from heated baking soda.


  • Where did the droplets on the test tube come from?

The droplets come from the hot gas touching the cooler surface at the top of the test tube.


  • Describe the color of the liquid in each test tube?

The heated test tube's color is a dark yellow, and the non-heated test tube is a light honey yellow color.


  • Are the two white powders the same substance?

No, they are not the same substance, because when the first test tube got heated the substance inside of it changed, we know this because it was a different color from the non-heated test tube.


Terms to Know


  • Control Group- unheated test tube
  • Experimental Group- heated test tube
  • Indicator- tea (showed you that the heated test tube was not baking soda)
  • Variable- something you want to measure

- Independent Variable: causes a change in the dependent variable (ex: heat)

- Dependent Variable: and example would be the color of the tea


  • Control factor- we had control over it

- Examples: same type of tea, same amount of baking soda, same amount of tea, same stirring time, and same size of test tubes



Box Question #1


  • Why do you think baking soda is used in baking?

It releases gas when heated, which helps dough/batter to rise and get fluffy. (Ex: cupcakes, cookies, etc.)



Part 3: Reaction in a Bag

Substances:


Phenol Red (Red Liquid)

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


Calcium Chloride (Calcium and Chlorine) (one of the two substances)

  • Mildly acidic
  • Hydrotopic: attracted to water (absorbs water)
  • Is used in canned vegetables to keep them from getting moist, electrolyte sports drinks, and it flavors pickles


Sodium Bicarbonate (Baking Soda) (the second substance)

  • Not acidic
  • Can be used in baking, cat litter, toothpaste, and laundry detergent


Purpose:

The purpose of this lab was to see what would happen when you mixed different substances together. Substances include phenol red, calcium chloride, sodium bicarbonate, and water.


Part 4: Volume Notes

Unit of Measurement
  • The unit of measurement for volume is cm3 (cubic centimeter)
  • The formula for volume is length x width x height (l x w x h)
  • The standard unit of length is the meter (m)
  • 1 centimeter (1 cm) = .01 m
  • 100 centimeters (100 cm) is equal to 1 meter (1 m)


Volume of Liquids

  • Use a graduated cylinder to measure volume
  • Always check the intervals on the scale
  • The units is milliliters (mL) OR cubic centimeters (cm3)
  • One milliliter (1 mL) is equal to one centimeter (1 cm)
  • Read from the bottom of the meniscus


Box Questions #3-8

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

50 mL are required to fill a graduated cylinder.


  • Rectangular box A has a greater volume than rectangular box B but the length of box A is less than the length of Box B. How is this possible?

This is possible because Box A has a greater width.


  • Adding a stone to a graduated cylinder containing 25.0 cm3 of water raises the water level in the cylinder to the 32.0 cm3 mark. What is the volume of the stone?

The volume of the stone is 7.0 cm3.


  • A student has a large number of cubes that measure 1 cm along each edge.

A: How many cubes will be needed to build a cube that measures 2 cm along each edge? In order to build a cube that measures 2 cm along each side 8 cubes will be needed.


B: How many cubes will be needed to build a cube that measures 3 cm along each edge? In order to build a cube that measures 3 cm along each edge 27 cubes will be needed.

C: What is the volume, in cubic centimeters, of each of the cubes in (a) an (b)?

The volumes are 1 cm3 and 3 cm3.


  • One rectangular box is 30 cm long, 15 cm wide, and 10 cm deep. A second rectangular box is 25 cm long, 16 cm wide, and 15 cm deep. Which box has the larger volume?

Box B has the larger volume.


  • Figure A shows a cone-shaped graduate used for measuring the volume of liquids. Why are the divisions not equally spaced?

As the surface increase the depth decreases.


Remaining Box Questions

Box Questions #9-13

  • A: Estimate the positions of arrows / and // in Figure B(a) to the nearest 0.1 cm. Can you estimate their positions to 0.01 cm?

The position of arrow / is 1.2 cm and the position of arrow // is 3.8 cm. You cannot estimate their positions to 0.01 cm.

B: Estimate the positions of arrows ///, IV, and V in Figure B(b) to the nearest 0.01 cm. Can you estimate their positions to 0.001 cm?

The position of arrow /// is 1.65 cm, the position of arrow IV is 2.53 cm, and the position of arrow V is 4.50 cm. You cannot estimate their positions to 0.001 cm.

C: Why should you report the positions of the arrows in part (b) to the nearest 0.01 cm and not to the nearest 0.1 cm?

You should do this, because it is more accurate.

  • What part of a cubic centimeter do the smallest divisions on each of the graduated cylinders in Figure C represent? Express your answer as a decimal.

Graduated Cylinder A has a measurement of 0.1 cubic cm and Graduated Cylinder B has a measurement of 0.2 cubic cm.

  • 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?

The level of liquid in (a) is 4.0 cm3 and the level of liquid in (b) is 1.25 cm3.

  • Three students reported the length of a pencil to be 12 cm, 12.0 cm, and 12.00 cm. Do all three readings contain the same information?

12 cm could have been rounded up from 11.5 or rounded down from 12.4. 12.0 cm could have been rounded up from 11.95 or rounded down from 12.04. Lastly, 12.00 cm could have been rounded up from 11.999 or rounded down from 12.004.

  • What advantage is there in making graduated cylinders narrow and tall rather than short and wide?

It is easier to read, because the lines are further apart because there is less surface which equals more depth.

Mass Notes

Beqa- ancient standard mass used in Egypt


  • Earliest balance found in Egypt (approximately 7,000 years old)
  • Mass standard unit is grams
  • 1 kilogram=1,000 grams
  • 1 kilogram= 2.2 pounds

EXTRA NOTES

Post-Lab 2.1

-6 out of 10 (60%) groups had a decrease in mass


-Considering the sensitivity of the balance (-0.02-+0.02)

-3 out of 10 groups could have no delta M


EXPERIMENTAL ERRORS:

-Not drying off the cap=Water in the 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=lack of salt for MF

HISTOGRAMS

A histogram is a diagram consisting of rectangles whose area is proportional to the frequency of a variable and whose width is equal to the class interval. A histogram is similar to a bar graph and is used for financial purposes.


An interval is a pause; a break in activity. In a histogram a interval is a break between one number to the next.


The first thing you must do when you have a histogram is find the largest and smallest numbers you must graph.


THE HISTOGRAM RULE: If data falls on a line it is graphed in a column to the right.

Conservation of Mass

Closed system- a space where nothing can enter or leave


Groups that possibly have no ∆M (consider sensitivity of balance)


Law of Conservation of Mass: In a closed system mass will remain constant, regardless of the actions of the processes inside the closed system.

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CHAPTER THREE

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.

EX: Sharp-object, stainless steal-substance, small-object, tar-substance


Post Lab 3.2

Errors:

-Using the same long cylinder twice.

-Cylinder wet when massed the mass goes up.

-Water splashes out of the graduated cylinder the volume goes down


Density:

-A characteristic property

-Is specific to liquids, solids, and gases

-Can help to identify substances

**DENSITY FORMULA:D=M/V


Post Lab 3.5

The histogram show that cube one and slab are most likely the same substance. Cube 2 is a different substance.

Why do lab groups get different density calculations for their rocks? All have different densities because the rock is formed by many substances being compressed together. Different substances=different densities.

Errors:

-Measure the same side twice

-Water splashes out of graduated cylinder

-Find the volume of rock before-mass the density goes up

-Paint chips off of objects-the mass goes down


Post Lab 3.6

Errors:

-Not rinsing out cylinder between substances.

-Cylinder is not re-massed empty.

-Outside of cylinder is wet during mass empty


  • Substance A-magnesium sulfate:epsom salt
  • Substance B-water


Post Lab 3.7

Errors:

-Make sure hand seals bottle

-Do not touch tablet after Mi

-Put foil back for MF

-Spill water when finding volume of bottle


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