IPS Exam

Sydney Aronberg

Safety

Safety Equipment-
  1. Goggles- keep them over your eyes until Mr. Leeds says to put them away
  2. Fire extinguisher
  3. Fire blanket
  4. Eye wash/shower

For Every Lab-

  1. Report accidents to Mr. Leeds IMMEDIATELY
  2. Nurse extension: 2828
  3. Clean-up completely

Chemicals-

  1. Never taste chemicals
  2. Never waft solids
  3. Always waft liquids
  4. Do not touch chemicals
  5. Always wash you hands with soap and water after labs
  6. If chemicals touch your skin: flush skin with water for 1 minute and notify Mr. Leeds

Glass-

  1. Hot and cold glass look the same
  2. Never used chipped or broken glass
  3. Dispose broken glass in proper trash
  4. Never use force to remove or insert glass

Alcohol Burners-

  1. Roll up sleeves
  2. Put up long hair
  3. Never walk away from a lit burner
  4. Never point the open end of a hot test tube at yourself or someone else
  5. Do not look down into a test tube if it is being heated
  6. Make sure burner is capped and flame is out when you are done

Reaction In A Bag Lab

exothermic reaction- heat is produced

endothermic reaction- cold is produced

Error-

- hole or rip in the bag: you wouldn't know a gas is being produced

Red Liquid= Phenol Red

used as a ph indicator

Solid A= calcium + chlorine

acidic, hydrotropic- absorbs water

Solid B= sodium bicarbonate

sodium bicarbonate- baking soda, alkaline

Heating Baking Soda Lab

Control Group- unheated test tube

Experimental Group- heated test tube

Indicator- tea

Independent variable- heat

Dependent variable- color of tea

Control factors- same type of tea, same amount of baking soda, same amount of tea

Experimental Error- hole in tubing, stopper isn't tight, not cleaning stirring rod


Volume

Volume of Solids-

The unit of measurement is cm3. To find the volume you must multiply l x w x h. A standard unit of length is a Meter (M). 1 cm = 0.01 M and 100 cm = 1 M.


Volume of Liquids-

A graduated cylinder is used to measure the volume of a liquid. You must always check the intervals or scale of a graduated cylinder. The unit of measurement is milliliters (mL). You should always read volume from the bottom of the meniscus.

Using A Balance

Steps for using a Balance-

  1. Make sure the pan is clean and dry
  2. "Zero Balance" by pushing riders to the left and using the adjustment knob
  3. *Never switch pans
  4. *Pick up balance by the red bar

Displacement of Water Lab

In this lab, we determined the volume of just sand (no air space). We did this by taking sand and water and combining them. We discovered that about 40% of every group's sand is airspace.

Experimental Errors- sand sticks to sides of wet cylinder, if you poured water into sand

Volume of Sand Alone- sand and water - water

Volume of Air Space- dry sand - sand alone

Fraction of Sand that is Air- air (over) dry sand


Mass

  • Beqa- ancient standard mass used in Egypt
  • earliest balance found in Egypt (about 7,000 years old)
  • standard unit of mass- grams
  • 1 kg = 1,000 grams
  • 1 kg = 2.2 lbs

Sensitivity of a Balance Lab (Part 1)

In the first part of the lab, we mass a penny and stopper alternately 4 times. We realize that each time we have a slightly different mass for the penny. This is because we all read the balance differently.

To find the mass of a single square- mass of 20 x 20 square (over) 400

*if the range (biggest-smallest) is larger than the sensitivity of a balance than some group made a mistake (applying to a group of data)

Sensitivity of a Balance Lab (Part 2)

In the Sensitivity of a Balance lab, we decided what the sensitivity of our balance is. The sensitivity is how much mass must be put on the balance for the balance to realize there is a difference. In the second part we cut out a square and calculate the mass of 1 square. We then figure out how many squares are between 0.003 and 0.007. We cut ten groups of that number and keep adding it to the stopper. We record each mass each time.

Delta- triangle symbol, change

Delta M- change in mass

To find the Delta M- ending mass - initial mass of stopper

To find the sensitivity- Delta M (over) number of yes's


Sensitivity of a Balance Lab Notes

Pennies:

  • Before 1982: 95% Copper, 5% Zinc
  • After 1982: 2.5% Copper, 97.5% Zinc computer technology made the price of copper go up
  • 1943: made of steel and zinc copper was needed for shell casings (bullets for WW II) a 1943 copper penny has sold for $82,500

Sensitivity of Balance:

  • sensitivity- the lightest mass that you can expect the balance to detect
  • (+,-) the margin of error when you mass something

The Mass of Dissolved Salt

We found the mass of salt and a bottle with water (the salt not mixed). Then we mixed the salt in the bottle to see if adding salt to the water created a decrease/increase/no change in mass.


Mi- Mass initial

Mf- Mass final

to find ∆M... Mf-Mi

Errors=

if you clean pan between Mi and Mf

outside of bottle is wet during Mi

if you shake bottle (spill, leak)

To get dissolved salt back: let water evaporate, there will be same amt. of salt

*if someone is between -.02 and .02, it is possible they got no change*

Histograms

1st step: find least and greatest number you have to graph

interval- one full line to the next

*HISTOGRAM RULE*- if data falls on a line, graph in the column to the right

Ice Ice Baby Lab

During this lab we found the mass of ice in a bottle then we found the mass of water (the same ice melted) and we wanted to see if there was a increase/decrease/no change in mass.


Mi of Ice- bot/cap/ice - bot/cap

Mf of Water- bot/cap/water - bot/cap

∆M- Mf-Mi

Condensation:

Where does it come from? warm water vapor in air touches cool surface of bottle

How does this affect the lab? it will add extra mass for the Mf

Errors=

not wiping of condensation

bottle is wet during Mi

shaking bottle may cause leak

Copper and Sulfur

yellow smoke- water in sulfur turns to vapor and rises in tube

when it cools- sulfur bonds with copper and forms sulfur sulphide

sulfur is hydrotropic


errors:

1. rubber sheet has a hole

2. sulfur ticks to sides of tube

3. clean pan b/w mi and mf


Percentage of Change-

∆M/Mi= x/100

The Mass of Gas

alka-seltzer= antacid (stops acid and pain reliever


has... aspirin, citric acid, adn sodium bicarbonate

Conservation of Mass

closed system- a space where nothing can leave or enter



LAW OF CONSERVATION OF MASS:

in a closed system, mass will remain constant, regardless of the actions of the processes inside the closed system


**all changes should be close to zero because of sens. of balance

Properties

Characteristic Properties:


Property of an object: does not tell you what it is made of

Property of a substance: helps identify what the object is made of


  1. Sharp- object
  2. Heavy- object
  3. Stainless-steel- substance
  4. Knife- object


  1. Small- object
  2. Chunk- object
  3. Black- object
  4. Tar- substance


  1. Beautifully carved- object
  2. Wooden- substance
  3. Chair- object

Mass and Volume

Errors:


cylinder is wet during the mass (from volume)- add mass

if water splashes out of g. cyl.- less volume


1. objects that are made of the same substance that have the same volume will have the same mass

2. the mass of an 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

Density

D= m/v


aluminum: 2.7 g/cm3

brass: 8.5 g/cm3

The Density of a Solid

the histogram shows that cube 1 and the slab are most likely the same substance.

cube 2 is probably different.



Density of a Liquid

Errors:


-not rinsing out grad. cyl. between substances

-dry grad. cyl. between masses

- not re-massing grad. cyl. for 1st mass


Epsom Salt=

-magnesium sulfate

Density of a Gas

Errors:

-if you don't put the foil back for the Mf

- if you touch the tablet after Mi

- stopper isn't on tight