IPS Big Exam
Study Guide
Lab Safety
FOR EVERY LAB
- Nurse extension 2828- Goggles must always be on your face for the entire lab
- Report all accidents and spills to Mr. Leeds
SAFETY EQUIPMENT
- Fire extinguisher
- Fire blanket
-Eye wash/ shower
CHEMICALS
- Never taste chemicals
- Always waft liquid(never waft powders)
-Avoid touching chemicals
- Always wash hands with soup after lab
GLASS
-Hot glass and cold glass look the same
-never use chipped or broken glass
-Never force to remove or insert glass
ALCOHOL BURNERS
-Roll up sleeves, put up long hair
-Never walk away from a lit burner
-Never point the end of the test tube at yourself or anyone else
-Do not look down on a test tube when it is being heated
DILUTING ACID
-Acid must be added to the water
-Never add water to acid
-This could cause a exothermic reaction
Water is less dense that acid so it will sit on the top of acid and could splash out
END OF EXPERIMENT
-Make sure burner is capped and flame is out
-CLEAN UP
Chapter 1
1. identify problem
2. gather information
3. theory or hypothesis
4. test theory(experiment)
5. analyze data
6. conclusion
Reaction in a bag
Purpose: To record observations that occur when substances are combined
(look at lab report)
Chapter 1 Vocab
Observation: information obtained by senses often by direct measurement
Inference: a conclusion based on a know observation
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 for solids liquids and gases
Volume Displacement Technique: quick and easy way to determine the volume of solids and gases
Mass: the amount of matter in a substance
Meniscus: the curved portion of a liquid when in a container. must read at eye level.
Baking Soda
- A gas collected in the water bottle and it started to push the water out
-the gas came from the baking soda
-Condensation forms when the hot air touches the cool surface and makes it go from a gas to a liquid.
-The droplets on the top of the test tube come from the water vapor in the air
- Going from hot to cold makes a gas
Control group: Unheated baking soda and tea
Experimental Group: Heated baking soda and tea
Indicator: Tea
Control Factors: amount of tea, amount of baking soda, type of tea, stirring time
Volume Notes
- Unit of measurement is cm3
Volume= LWH
1 centimeter=.01 meters
unit cube=a small cube with 1cm on each side
Volume of liquids
Use a graduated cylinder to measure this
1mL=1cm3
1.4 Experiment
sand+water
-water
= sand alone
dry sand
-sand
=air space
Errors
1. Sand could get stuck to the side of cylinder(wont get extra measurement for V of sand+water)
2. Read sand level not water level
Space within the sand is about 40%
1.8 sensitivity of balance
sensitivity: how much error your balance makes
sensitivity= change in mass DIVIDED by the number of yes's
Chapter 2
histogram: a bar graph that shows the number of times a value is represented for a large sampling of a group
Conservation of mass: in all changes mass is exactly conserved, provided nothing is added or allowed to escape, must be a closed system! NOT TRUE FOR VOLUME
Laws of nature: guessed generalizations based on many experiments. Can be adjusted when necessary to account for any changes in the limitation of a law.
2.1 mass of dissolved salt
as salt dissolves volume decreases
MF
-MI
= change in mass
mi= initial mass
mf- mass final
-the mass decreases when salt dissolves
may be because of the sensitivity of the balance which will always be around .02
Errors
water spills
walt spills
didnt clean pan
the outside of the bottle-wet
2.4 mass of ice and water
Condensation=water
water vapor was warm and when it touches the cool surface it turns into a liquid
condensation would add mass so you need to wipe it off
errors
condensation
shake bottle
cap not all the way on-water evaporates
if you don't let the ice fully melt
2.5 the mass of copper and sulfur
errors
shaking test tube
rubber sheet has a hole
stop heating before reaction ends
rubber sheet not fully sealed
2.6 the mass of gas
How do you find the mass of a gas?
errors
outside of bottle wet
if inside of cap is wet (when you put the tablet in it)
loosening cap-water falls out
not all gas is released
if cap is not sealed on tight
laws of conservation of mass: in a closed system mass will remain constant, regard less of action of the processes inside the closed system.
Exception: nuclear reaction....
Chapter 3
property of an object: describes the object itself
Property of a substance: identity what the object is made of
characteristic properties: properties that show differences between substances
plateau: a flat portion of a graph. indicates no change in the dependent variable
phase diogram: a graph that shows the changes in a 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
3.2 mass and volume
the mass of an object will double if its volume doubles
object that have the same volume but are made of different substances will never have the same mass
3.3 density
D=M DIVIDED by volume
3.5 density of solids
errors
measure one side twice
find volume of rock before its mass
mix up cubes
measure from the edge of the ruler
The rocks have different densities because the rock is formed by many substances being compressed together. different substances=different densities
3.6 density of liquids
errors
cylinder could have been contaminated (another liquid in it)
if you dry out the cylinder after you mass it
cylinder is wet when massed
liquid sticks to the side of the cylinder
magnesium sulfate=epsom salt
3.7 density of a gas
errors
remove stopper before tubing (gas would be released)= more water gets pushed out, makes volume bigger=D smaller
hand doesnt seal bottle when removing it (water pushed out=volume bigger, density smaller
forget to put the foil in the pan for mf ( makes mass increase to high)=density bigger
takes to long to insert tubing into bottle (not as much water will get pushed out of bottle.) =volume down, density up