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

Scientific Method

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

Vocab

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

Vocab

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