Study Guide

Science Exams

Notes

Reaction in a Bag

1) Red Liquid
  • Phenol Red
  • Used as a ph indicator
  • Below 7 turns yellow
  • Above 8 turns pink
2) Ph Schale
  • Measures acidity
  • Goes from 0-14
  • 0-7 acid
  • 7- neutral
  • 7-14 alkaline

Heating B. Soda

1. Test Tube

  • Condensation comes from touching cooler surface at top of test tube cools back to a liquid
  • gas comes from heated baking soda

Control Group- Unheated t. tube

Experimental Group- Heated t. tube

Indicator- Tea ( showed that heated t. tube wasn't b.soda)

Variable- Something you want to measure

Independent Variable- Causes a change in dependent variable -Temp (heat)

Dependent Variable- Color of tea

Control Factors- Same type of tea, same amt. of b.soda, same amt. of tea, same stirring time, same size t. tube

Exp Errors- Hole in tubing- bottle won't fill, don't clean stirring rod--> contaminated



Volume

Unit of Measurement- cm3 (cubic centimeters)


Volume- LxWxH (AxBxC)

Standard unit of length- meter (m)

1 Centimeter (1cm)= .01 m

I----> 100

100 cm = 1m

Unit Cube

A small cube 1 cm on each edge (1cm3)

Volume of Liquids


  • Use a graduated cylinder to measure volume
  • always check the intervals or scale
  • units- milliliters (mL) or cm3
  • 1 mL== 1cm3
  • Read from bottom of meniscus


Single Pan Balance

  • Check that pan is clean and dry
  • Always zero balance before each massing
  • push all riders to zero (left)
  • Use adjustment knob if needed
  • Never switch pans
  • pick up balance by red bar only
  • dont zero balance when done


Mass

Bega- ancient standard mass used in Egypt


- earliest one found in Egypt (approx. 7,000 yrs old)

Standard unit for mass: grams (g)

1kg= 1,000 g

1kg= 2.2 lbs


Sensitivity of Balance

+

- Means the margin of error when you mass something


Histograms

Type of graph (similar to bar graph)


Used for financial

If data falls on a line it is graphed in column to the right

Find largest and smallest number you must graph when you draw a histogram


Condensation of Bottle

Comes from warm water vapor in air that touches a cooler surface of bottle, it turns from a gas to a liquid.


Copper and Sulfur

Melting point of Copper- 1,100˚C (2,000˚F)


Melting point of Sulfur- 112˚C (235˚F)

Yellow Smoke- water in sulfur turns to vapor (gas) and rises in test tube

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

Alka-Seltzer

Antacid and pain reliever


Ingredients:

Aspirin

Citric acid (small) (flavor?)

Sodium Bicarbonate (produces gas)

Conservation of Mass

Closed System


Law of Conservation of Mass

In a closed system mass will remain constant regardless of the actions of the processes inside the closed system.


Main Idea:

Mass will remain the same if its in a closed system.


Characteristic Properties

Property of an object- does not tell you what it is made out of.


Property of a substance- this helps you to identify what the object is made out of.

Mass and Volume

1) Objects that are made of the same substance that have the same volume, will have the same MASS regardless of their shape

Ex: Long Aluminum Cylinder and the small aluminum cylinder

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.

Ex: Brass and aluminum cylinders

Density

1) A characteristic property

2) is specific to liquids, solids, and gases

3) can help to identify substances

Rock

Why do different groups get different density calculations for their rocks?


- All have different densities because rock is formed by many substances being compressed together. Different substances equal different densities.

Safety

For every lab
  • Goggles must be kept over your eyes until Mr. Leeds says ot put them away even if you are already finished cleaning up
  • Report all accidents/spills to Mr. Leeds immediately
  • Try your best to use common sense
In Case Emergency
  • Nurse: ext: 2828
Safety equipment in classroom
  • Fire extinguisher
  • Fire blanket
  • Eye was/shower
Chemicals
  • Never taste chemicals even if they look yummy!
  • Always waft liquids to detect odor
  • Never waft solids or powders!
  • Avoid touching chemicals
  • Always wash hands with soap and water after lab
  • If chemicals touch skin: flush skin with water for 1 minute and notify Mr. Leeds
Glass
  • Hot glass and cold glass look the same
  • Never use chipped or broken glass, tell Mr. Leeds and dispose of broken glass in proper trash
  • Never use force to remove or insert glass
Alcohol Burners
  • Roll up sleeves, put up long hair, not just pull back or you cannot do the lab
  • Never walk away from a lit burner
  • Never point the open end of a hot test tube at yourself or someone else
  • Do not look down into a test tube/beaker wile it is being heated
  • Make sure burner is capped and flame is out when done
End of Experiment
  • Clean up area and materials completely or you will lose points!
  • Make certain that burner is out if one was used
  • Keep goggles on over eyes until Mr. Leeds says to put them away


Vocab

All Lessons

Bega- ancient standard mass found in Egypt

Shell casings- Bullets

Meniscus- The curve point of where the water in a graduated cylinder falls. Read at the bottom for volume determination

Variable- Something you want to measure

Independent Variable- Causes a change in dependent variable

Sensitivity of a Balance- The lightest mass you can expect the balance to detect

Closed System- A space where nothing can enter or leave

Hydrotropic- Attracted to water

Density- Characteristic property, helps identify substances, specific to liquids, solids, and gases.

Interval- One line to the next.

Autonomous- independent

Exothermic- Give off heat

Endothermic- Give off cold

Red Liquid- Phenol Red

pH Scale- measures acidity

cubic centimeters- unit of measure for volume

Volume- amount of space something occupies

cm- unit of measurement for length



Other things to know that aren't on here

Calculations

Box Questions

Blue Dots

Histograms and Graphs

Tests/Quizes

Quesiton 5 part A

Big image

Chapter 2 Test

Part 1 Errors

1) If in the Mass of Gas lab, the cap is not on tightly what would the outcome be?

Lose Mass, gas escape

2) In the Mass of Copper and Sulfur lab if there is a hole in the rubber sheet what would the outcome be?

Lose Mass, gas escape

3) In the Mass of Ice and Water lab if you don't wipe off the condensation on the bottle with water and ice what is the outcome?

Gain Mass, during Mf.

Part 2 Analysis

1) During Mass of Ice lab a group forgot to wipe condensation off bottle what should they do?

Start over

2) In all 4 experiments from Ch.2 in all the labs there should be no change in mass because?

Newton's laws of motion

all the labs followed einstein's theory

in all 4 labs everyone in class calculated no change in mass

Law of conservation of mass

3) If you were to place a bottle with water in it into a freezer, the liquid would solidify, what is a possible error you should be aware of?

All of the above

Condensation may form on the outside of the bottle

Condensation may form on the inside of the bottle during the Mi and then freeze

The water could start boiling and push the cap off

Part C: Calculation

1) What is the percentage change in mass of the reacting substances? (round to tenths)

∆M divided by Mi= % over 100..... -0.026 divided by 1.843 equals x over 100= -1.4%



Chapter 3.1-3.8

2) Two Chainz necklace contains 0.8 kg of platinum. If the density of Platinum is 21.4g/cubic centimeters, what is the volume of his necklace?

D= m divided by v.... 21.4=800 divided by v, v= 37.4cubic centimeters

∆M is the mass of gas

∆V is the volume of gas

Part B:

1) In order to calculate denisty we found both the mass and volume of the liquid in the graduated cylinder because it is the most accurate method and we did not have to transfer liquid.

2) During the density of gas lab the rubber tubing is incorrectly inserted near the bottom of the bottle, this will cause less gas to collect in the bottle.

3)If the error in the one above is made it will have the following affect: volume decrease, density increase.

4) when calculating the density of a rock it would be an error to find the volume prior to massing.

5) WHen the alka seltzer tablet is mixed with water, sodium bicarbonate within the tablet releases carbon dioxide.

6) In the density of a gas lab a student forgets to include the foil for the mf, the result is the mass of gas increases, density increases.

7) Epsm salt is the marketing name for Magnesium Sulphate.


Chapter 1

In a rectangular box the following measurements were found: six cubes fit exactly alone one edge, and five cubes fit exactly along another edge. However, after seven horizontal layers had been stacked in the box, a space at the top was left unfilled.


- If the height of the space was half the length of an edge of a unit cube, what was the volume of the box?

LxWxH= V..... 6x5x7.5.... V= 225cubic centimeters

2) What is the mass of an iron bar that is 2cm x 4cm x 11cm? (1cubic centimeter of iron has a mass of 7.8g)

2x4x11x7.8..... 88x7.8= 686.49 cubic centimeters

3) A volume 87 cubic centimeters of dry sand is added to 46 cubic centimeters of water of r a total volume of 104 cubic centimeters. (round to whole number, convert fractions to percentages)

V. of dry sand- 87 cubic centimeters

V. of water- 46 cubic centimeters

V. of sand and water- 104 cubic centimeters

V. of sand alone- 58 cubic centimeters

V. of Air space- 29 cubic centimeters

% of dry sand that is air- 67%

% of dry sand that is air space 33%

104-46= 58.......

58 divided by 87 = x over 100= 67%

41 divided by 87= x over 100= 47%

a) What is the volume of water that fills the air spaces in the dry sand?

87-58= 29 cubic centimeters

b) What is the volume of the water that does not fill the air spaces in the sand?

46-29= 17 cubic centimeters

4) To stay physically fit, Mr. Leeds is constantly training (and injuring himself). He weighs a trim 178 lbs. What is his weight in kilograms? (round to whole number)

178 divided by 2.2= 81kg

5) Use the following data to find the sensitivity of the balance used: (round to hundredths)

14.39-14.30= 0.09..... 0.09 divided by 6= 0.015 which equals 0.02g

6) FIve ips scholars use the same single pan balance to mass their friend's ring. None knew the results of the others. THeir results are listed in the table below:

a) Did any students make a mistake in their massing?

Yes their range is 0.045 which is much bigger than the sensitivity of the balance. (0.01-0.02)

Part B: Lab Experiments:

1) During the Heating Baking Soda Experiment a lab group does not realize that they have a hole in their rubber tubing. How will this affect their understanding of the lab?

They wouldn't know a gas was being produced!

Part C: Measurment

1) Identify each mass, volume or other means.

3 cups flour- vol

1 tablespoon baking powder- vol

11 pound can of pumpkin- mass

1/2 teaspoon vanilla- vol

Cinnamon to taste- other

1/2 cup milk- vol

2) Identify volume, mass, or count

Auditorium- count

Bridge- mass

Saucepan- vol

Water tank- vol

3) What would happen if Mr. Leeds gave you a range very small for 10 groups of squares?

You would be adding a lot of squares