IPS EXAM EXPIERENCE
December 18-19
By Rodrigo Torrejon
Safety Quiz Notes
Emergency number: 2828
CHEMICALS
Never taste chemicals
Always waft liquids
Never Waft Solids or powders.
If chemicals touch skin, wash with soap and water and notify Mr. Leeds
GLASS:
Hot and Cold Glass look the same
Never used chipped or broken glass
Never use force to remove or insert glass
ALCOHOL BURNERS:
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
END OF EXPERIMENT:
CLEAN-UP AREA & MATERIALS COMPLETELY!!!!
Keep goggles on until Mr. Leeds says to put them away.
Reaction in a Bag Lab Notes
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
- 0-6 is acidic
- 7 is neutral
- 8-14 is alkaline
SOLID A:
- Calcium Chloride
- Acidic
- hydro-topic: attracted to water (absorbs water)
SOLID B:
- Sodium Bicarbonate (Baking Soda)
- not acidic
EXPERIMENTAL ERRORS:
- a hole in the bag: you would not see that gas was produced.
CHEMICAL REACTIONS:
- A+liquid= exothermic reaction (hot)
- B+liquid= endothermic reaction (cold)
- A+B+liquid= gas
CHAPTER 1
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.
PART 2:
- 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
EXPERIMENTAL ERRORS:
- 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
EXTRA QUESTION:
- Less or equal because the condensation comes from the baking soda. It cannot produce more than itself.
1.2 Volume notes
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
UNIT CUBE
- a small cube 1 cm on each edge
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 4.85 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
BOX QUESTIONS 1, 3-13
- When heated, baking soda causes a gas which helps dough/batter to rise (cupcakes, bread, cakes, etc.)
- N/a
- 50 cm³
- If A has a greater mass, but B has a greater length, how is possible? : A has a greater width and/or height.
- 7 cm³
- a is 8 cm³ and b is 27 cm³
- 2nd box has a greater volume
- The width is bigger on the top than the bottom. As the surface increases the height decreases. Vice versa
- it makes it more accurate
- (a) is 0.1 cm³, (b) is 0.2 cm³
- (a) is 4.0 cm³, (b) is 1.35 cm³
- 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
- 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
Data:
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
0.39
% of sand that is air
39%
Experimental Errors:
- sand sticks to sides of wet cylinder: volume of sand of water would be low.
- 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
________________
400
Delta mass
____________ = Sensitivity of a Balance
number of yes's
Ending Mass (#10)
- initial mass of object
_________________________
delta mass
Experimental Errors:
- if squares were not cut correctly: it could affect the outcome of the experiment
- if graphite got on the square: then mass would be altered
1.8 Post Lab
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 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
TEST
- 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.
- 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
67%
% of Dry sand that is air Space
34%
- What is the Volume of water that fills the air spaces in the dry sand? 29cm3
- 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
Count
Mass
Volume
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
measurement.
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
experiment.
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
substance.
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
gases)
Meniscus- the curved portion of a liquid when in a container. Must read
the bottom of the meniscus- at eye level- for proper
measurement.
CHAPTER 2
Post Lab 2.1 The Mass of Dissolved Salt
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
HISTOGRAM
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
2.5 The Mass of Copper and Sulfur
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
- 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
Law of Conservation of Mass
In a closed system, Mass will remain constant, regardless of the actions of the processes inside the closed systems.
ALL CLOSED SYSTEMS HAVE NO CHANGE IN MASS
Chapter 2 Test
- 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:
START THE LAB OVER
CHAPTER 3
Chapter 3 Vocab
Characteristic Properties- Properties that show differences between
substances.
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
substance.
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
g/cm3.
3.1 Characteristic properties
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
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
- objects that are made of the same substance volume will have the same mass (regardless of shape)
- The Mass of a 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.
3.3 Density
Aluminum= 2.7 g/cm3
Brass= 8.5 g/cm3
3.5 The Density of a Solid Lab
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
- 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
CHAPTER 3 TEST
Example:
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
Mf-Mi
31.86
- 32.64
-0.78
0.78g
-------- = 0.0038613 g/cm3 = 3.9 x 10 (to the negative cubed)
202 cm3
- 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 (mouth) of the bottle. This will cause: less gas collected in the bottle
- 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