IPS Exam Study Guide
Lab Safety
- Nurse ext 2828
- Remove goggles when Mr. Leeds tells you.
- Report accidents and spills to Mr. Leeds immediately.
- Never waft solids/powders.
- If contact with chemicals occurs, notify Mr. Leeds, and flush skin with water.
- Hot and cold glass look the same.
- Put up long hair for Alcohol Burner.
- Never walk away from a lit burner.
- Do not look down into a test tube/beaker while it is being heated.
- Acid must be added to water.
-Water is less dnese than acid so it will sit on top of acid and could splash out.
Scientific Method
1. identify problem -the car won't start.
2. gather info -check how much gas there is.
3. form hypothesis/theory -the engine's battery is out.
4. perform experiment -put the jumpers on the engine and start it up.
5. analyze data -turn on the car.
6. conclusion -you go to your destination.
Reaction in a Bag
- in order for there to be a reaction, you must combine a solid with a liquid.
Scholar Reaction In The Bag Inquiry Demonstration and Lab Activity
Heating Baking Soda
experimental errors:
- stirring rod contamination
- stopper not snugly.
- hole in tubing (bottle would not fill with air)
- rubber band pops up (breaks)
additional notes:
- baking soda is used in cooking because it produces a gas that allows food to rise.
Lab 1.1 Heating Baking Soda
Measuring Volume by Displacement of Water
Why were lab groups instructed to use different amounts of sand?
- the purpose of having different amounts of sand is that about 40% of sand is air.
- sand sticks to the side of cylinder. (effect: level of water and sand will be lower)
- crack in funnel. (effect: wouldn't go in tube, would fall out)
- pour water into sand. (effect: water sits on sand. makes volume of it too high)
- read level of sand and not water. (effect: makes volume of sand and water lower)
- elevator-count, mass
- stadium-count
- bridge-mass
- bus-count
- water tank-volume
- freight car-mass
- theater-count
- sauce pan-volume
Lab 1-4 Measuring Volume By Displacement
Sensitivity of a Balance
- ending mass -initial mass of stopper = change of mass
experimental errors:
- pencil marks on paper (adds mass)
- cutting groups uneven
- balance not zeroed
- read balance incorrectly
The Mass of Dissolved Salt
experimental errors:
- cap is not on tight-water spills out (decrease in mass)
- cleaning pan between Mi and Mf (decrease in mass)
- salt spills when pouring into bottle (decrease in mass)
- not shaking long enough (decrease in mass)
- cap not dry (decrease in mass)
- remove cap before Mf (decrease in mass)
- outside bottle is wet and gets on bottle, then hand, and mass goes down (decrease in mass)
The Mass of Ice and Water lab
- condensation comes from water vapor touching the cooler surface of the test tube.
experimental errors:
- not wiping off condensation on outside
- shaking bottle (water could leak out)
- ice isn't fully melted
- bottle (outside) gets wet from putting in ice
- not drying the bottle/cap
- removed the cap before Mf
Lab 2-4
The Mass of Copper and Sulfur
experimental errors:
- rubber sheet not on tightly - gas can come up (decrease in mass)
- hole in sheet - wouldn't see gas (decrease in mass)
- shaking test tube (decrease in mass)
- clean pan between massing (decrease in mass)
2-5 Sulfer and Copper
Mass of a Gas
experimental errors:
- inside of cap is wet - start reaction (effect: change of mass)
- cap is not sealed - quickly and tight (effect: change of mass)
- outside bottle wet during Mi (effect: change of mass)
- water splashes out when gas is released (effect: change of mass)
- in a closed system, mass will remain constant, regardless of the actions of the processes inside the closed system
Lab 2-6 Mass of Gas
Mass and Volume
experimental errors:
- re-mass a cylinder (might get 2 same numbers)
- cylinder is wet when massing (mass goes up)
- not enough water in graduated cylinder (decrease in mass)
- water splashes out of graduated cylinder (turn graduated cylinder sideways and let object slide through) (decrease in volume)
additional notes:
- objects that are made of the same substance that have the same volume, will have the same mass (regardless of their shape)
- the mass of an 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
- standard unit of length = meter
- 1m =100 cm =0.01 m
Lab 3-2 Mass and Volume
Density of Solids
experimental errors:
- measure same side of cube/slab
- measure from end of ruler and not zero (volume goes down, density goes up)
- measure rock's volume before massing (mass goes up, density goes up)
additional notes:
- similar volume, heavier cube - a greater density
- all have different densities because the rock is formed by many substances being compressed together. Different substances = different densities.
- if volume goes down, the density goes up
Lab 3-5 Density of Solids
Density of Liquids
experimental errors:
- contamination cylinder (wet on inside)
-mix substances
- dry the cylinder after its massed (decrease mass)
- liquid sticks to inside walls of cylinder (mass and density go up)
additional notes:
- magnesium sulfate - epsom salt
Density of a Gas
experimental errors:
- hand not sealed on the bottle, so water leaks out - water is let out and bigger air bubble (volume goes up, density goes down)
- water in your pan during Mf (mass goes down, density goes down)
- hole in tubing, stopper not on tight, too slow putting tubing in - smaller air bubble - volume of gas is less. (volume goes down, density goes up)
- remove stopper before tubing (volume goes up, density goes down)
additional notes:
- sodium bicarbonate in alka-seltzer.
- it is important to cover the bottle, so water doesn't leak out of the bottle. Density of water outside and inside are same -nothing will move.
- the volume is the same as the volume of the gas - water leaves bottle because gas takes its place.
- you can find the mass of the gas by subtracting the Mf by the Mi (Mf-Mi = change of mass)
- gas is in alka-seltzer. gas is in Mi because it is locked in the tablet, but released by the water in the Mf because the tablet releases the gas.
- carbon dioxide is in the sodium bicarbonate.