IPS
Day 1- Calculations (look at box Qs) Day 2- multiple choice
Lab Safety
- Only waft liquids
- Wear safety equipment
- Don't touch hot glass
Nurse Extension: 2828
Eye wash, fire blanket, and fire extinguisher located all in classroom
ADD WATER INTO ACID
- water is less dense than acid so acid at bottom of cup
- this is safe so acid can't splash out
Scientific Method
NOT ALL THE STEPS SAME FOR EACH CLASS
For this class:
- Identify Problem
- Gather Info
- Form Hypothesis
- Do experiment
- Analyze Data
- Conclusion
Chapter 1
Reaction in a Bag (not in book)
Solid B: cold and doesn't dissolve
ONLY A AND B TOGETHER WITH LIQWUID MAKES GAS
Baking Soda Lab 1.1
Cold at top and hot at bottom
Water cycle forms inside:
- Hot gas touches cooler surface and turns back into liquid
- Evaporation, Condensation, then it starts all over again
- Condensation in glass tube and by stopper
Control Group: Unheated baking soda and Tea
Experimental Group: Heated baking soda
Indicator: Tea
CONCLUSION:
- Heated baking soda not actually baking soda- the control and experimental groups were diff. colors
- gas produced from baking soda
Sodium Bicarbonate = Baking soda
used in cooking because it creates a gas= fluffy cakes
More gas from baking soda than air (remember the gas filled in the bottle)
Notes for 1.2
L x W x H= Volume
1 centimeter= 0.01meter 1m= 100 cm
A small cube is 1cm3 on each edge
1 mL= 1cm3
1 kilogram= 1,000g
1Kg= 2.2 lbs.
Always check intervals before calculating volume in graduated cylinder
Always read ruler at zero line
Range of Estimation:
12 11.5-12.4
12.0 11.95-12.04
12.00 11.995-12.004
Why make graduated cylinder tall?
- easier to see
- less surface =more height
Why does the meniscus curve?
Surface tension
Sand and Water Lab 1.4
Why were lab groups instructed to use different amounts of sand?
To show everyone got same amount/ percentage and so we could compare
Experimental Errors:
- unseen hole in tube- funnel not straight so sand sticks to sides
- pours water into sand so V of sand and water HIGHER
- pour sand too fast and overflows
- funnel is wet so sand sticks to sides
Which is measured with Mass, Count, Volume?
Elevator..................................................................mass or count
Stadium................................................................,.count
Water tank ...........................................................volume
Bridge.......................................................................mass
Sauce Pan.............................................................. volume
Sensitivity of Balance Lab 1.8
(we used a penny and little squares from graph paper to help find sensitivity)
delta M= (triangle)m
Mf - Mi= (triangle)m
(i don't think Penny History will be on exam but just in case....)
Before 1982---- 95% COPPER 5% ZINC
After 1982----- 2.5% COPPER 97.5% ZINC
1943--- only zinc with plated steel
Balance sensitivity (margin of error) around 0.02
Not same each time you mass object, becasue of the margin of error (0.02)
Mf
-Mi
= #/ the yes
Look at final notes of Ch. 1 and in Textbook for sample answers
Observation- info obtained by the senses (often by direct measurement)
Inference- a conclusion based on 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.
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
Salt Lab 2.2
To examine if the mass of salt decreases when salt dissolves.
The mass of the sand stays the same- we all got different answers because of margin or error
- Salt on cap can get on pan inbetween Mi and Mf and clean it off
- Salt spills
- not dry cap
- not shaking long enough
- bottle is wet on outside during Mi and leaves a water ring and gets on hands
.................................................. HISTOGRAMS ......................................................
If data falls on a line, you graph it to the right.
Boundaries- columns on graph paper
Example:
A histogram has an interval with boundaries that are -0.01 and 0.01 with which values should be graphed in the interval?
A) -0.002..................... yes
B) -0.013.......................no
C) 0.................................yes
D) 0.01..........................no
E) 0.006........................yes
Ice Lab 2.4
No, mass will not change
Condensation comes from warm H2O vapor touching the cold surface of bottle. It changes from a gas to a liquid
Errors:
- Cap not tight
- Not drying bottle and cap
- not wiping off condensation on outside
- ice not fully melted
- you shake the bottle
- remove cap before the Mf
Copper and Sulfur Lab
No, the total mas does not change
Yellow gas is actually the little amount of water in sulfur with sulfur's yellow pigment
Why use a rubber sheet?
It is flexible so it can expand because of the gas
Exp. Errors:
- shake T. Tube
- cup flame before reaction ends
- band not tight enough (LOSS IN MASS)
- hole in rubber sheet (LOSS IN MASS)
- Clean pan between massing (LOSS IN MASS)
Mass of Gas Lab 2.6
No, the mass didn't change
Experimental Errors:
- Cap not on tight enough/ fast
- ring of water- wet on outside of bottle
- cap is wet
Alka-Seltzer has baking soda in it (sodium bicarbonate) and the b. soda releases the gas
END OF CH. 2
All ch. 2 labs should have had NO change
In a closed system mass will remain constant (same) regardless of the actions of the processes inside the closed system.
AS LONG AS EVERYTHING IS SEALED MASS WILL STAY THE SAME
Do Box Questions on page 39! #15-20
Chapter 3
Vocab for CH. 3 not on exam!
Lab 3.2 Brass and Aluminum rods
Answer:
Substance: YES
Shape: NO
Errors:
- cylinder is wet (mass up)
- remass cylinder
- not enough water
- too much water so no increments
- H2O splashes when object put in (volume down)------ TILT SO NO SPLASH
all aluminum cylinders should be 2.7000!!!
Mass and Volume Notes
- Objects that are made of the same substance and have same volume- will have same mass
- The mass will double if its volume doubles
- Objects that have the same volume, but are different substances will NOT have the same mass
3.3 Density
unit: g/cm3
Aluminum: 2.7 g/cm3
Density id a property of a substance
-----DENSITY NEVER CHANGES-----
3.5 The Density of Solids
Cube #2 has the greater density