# IPS

## Lab Safety

Remember:

• 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

• water is less dense than acid so acid at bottom of cup
• this is safe so acid can't splash out

## Scientific Method

This comes normally to people and can be applied to anything- car broken down, pen no work

NOT ALL THE STEPS SAME FOR EACH CLASS

For this class:

1. Identify Problem
2. Gather Info
3. Form Hypothesis
4. Do experiment
5. Analyze Data
6. Conclusion

## Reaction in a Bag (not in book)

Scholar Reaction In The Bag Inquiry Demonstration and Lab Activity
Solid A: Hot and dissolves

Solid B: cold and doesn't dissolve

ONLY A AND B TOGETHER WITH LIQWUID MAKES GAS

## Baking Soda Lab 1.1

Lab 1.1 Heating Baking Soda
Test Tube turns black-- not actually baking soda color changing

Cold at top and hot at bottom

Water cycle forms inside:

1. Hot gas touches cooler surface and turns back into liquid
2. Evaporation, Condensation, then it starts all over again
3. 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

• easier to see
• less surface =more height

Why does the meniscus curve?

Surface tension

## Sand and Water Lab 1.4

40% of all sand is air (REMEMBER CHART: sand n'water - water = sand alone)

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

Water tank ...........................................................volume

Bridge.......................................................................mass

Sauce Pan.............................................................. volume

## Sensitivity of Balance Lab 1.8

To discover the sensitivity of your balance. Also, to see if you repeat massing the same thing repeatedly, will it be the same?

(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

VOCAB:

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.

## 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

Experimental Errors: (ALL ABOUT LOSING MASS)

• 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

To determine if the mass of ice will change when it melts.

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:

1. Cap not tight
2. Not drying bottle and cap
3. not wiping off condensation on outside
4. ice not fully melted
5. you shake the bottle
6. remove cap before the Mf

Copper and Sulfur Lab, Raw footage

## Copper and Sulfur Lab

Does the total mass of copper and sulfur change when they are together?

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

Lab 2-6 Mass of Gas
Purpose: To explore if the mass will change when a solid and liquid produce a gas.

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

## All ch. 2 labs should have had NO change

Law of Conservation of Mass:

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

## Vocab for CH. 3 not on exam!

Lab 3-2 Mass and Volume

## Lab 3.2 Brass and Aluminum rods

To find if the mass of a 1cm3 object will depend on its shape or the substance it is made of.

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

1. Objects that are made of the same substance and have same volume- will have same mass
2. The mass will double if its volume doubles
3. Objects that have the same volume, but are different substances will NOT have the same mass

## 3.3 Density

M divided by V= 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

To use density to compare 3 metal objects to see if they are made of the same material

Cube #2 has the greater density