Science

Quiz #1

Safety

When doing a lab you should always be safe. One thing you should always do is where goggles. Goggles are something that will keep you safe so nothing gets in your eyes!



In case of an emergency call the nurse. Her number is 2828.


Around the classroom, there is some stuff to keep you safe. Those items include a fire extinguisher, and fire blanket, and an eye wash.




Another safety precaution is to never taste the chemicals. Although it may be hard because some look yummy, you must have self control. Always waft your liquids and never waft a solid or powder. If possible, avoid touching chemicals because you never know what will happen! Always remember to wear goggles when dealing with chemicals and when you finish, don't forget to clean up!


When dealing with glass, be very careful. Hot glass and cold glass look the same so pay attention when you are dealing with glass. NEVER use chipped or broken glass in a lab. If your test tube is cracked tell Mr. Leeds and then throw it away in the proper trash. Also, never use force when dealing with glass is it my crack and you will get hurt.


Alcohol burners, are another dangerous but useful part of science. When working with them take extra caution. Always roll up your sleeves and hair so they don't catch on fire. NEVER walk away from a lit burner. If something goes wrong and it is your fault that isn't good! Don't ever point the open end of a test tube at you are someone else as something can shoot out of it. Just use common sense to not look down into a lit burner and always cap a burner when done.


When the experiment is over, make sure to clean up. Keep your goggles on the whole time until Mr. Leeds give you permission to take them off!


Reaction in a Bag

In the Lab there were a few liquids.


Red Liquid:

Phenol Red


  • it is used a PH indicator
  • when it is below 7 it turns yellow.
  • when it is above 8 it turns pink.



PH Scale


  • it measures acidity
  • goes from 0-14
  • 0-6 is acid.
  • 7 is neutral.
  • 8-14 is alkaline.
  • When lemon juice is added it turns to 10.


In the lab we had 2 solids.


Solid A

Calcium Chloride


  • acid
  • hydro tropic (meaning it absorbs water)
  • it is used in canned vegetables to keep them for getting mushy.



Solid B

Sodium Bicarbonate (baking soda)


  • not acidic
  • used in toothpaste and laundry detergent.



Electrolytes


  • are used in sports drinks.
  • are used to flavor pickles.




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Heating Baking Soda

  • Condensation forms at the top of the tubes.
  • The water leaves the bottle.


Process:

  • Gas leaves the test tube. It comes from the baking soda.
  • Condensation is at the top. The condensation comes from the baking soda. The hot gas touches the cooler top of the test tube and turns back to liquid.


Differences:

  • the unheated one was foggier and was a light, dirty brown.
  • the heated one was a transparent, light brown.
  • They were different because the unheated is only baking soda and tea. The heated one is heated backing soda and tea but since they baking soda was heated it becomes a different chemical.


Control Group: Unheated


Experimental Group: Heated


In the lab the indicator was the tea.


Variables: a category you try to measure.


Independent Variable: Temperature. This causes changes in the dependent.


Dependent Variable: Tea. It depends on the independent.


Control factors:

  • same type of tea
  • same amount of baking soda
  • same amount of tea
  • same stirring time
  • same size test tube.


Experimental Errors:

  • a hole in the rubber tube.
  • stopper isn't put in snug.
  • The stirring rods weren't clean.



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Notes on Volume

Unit of measurement: cm^3



Volume: L x W x H


Standard unit of length: meter


1 centimeter=0.01 meter


100 centimeters- 1 meter


Unit Cube: 1 unit cube is 1 centimeter on each side.


  • use a graduated cylinder to measure volume. Always check for intervals or the scale.
  • Units=millimeter (mL) or cm^3

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Notes for Single Pan Balance

  1. Check that the pan is clean and dry.
  2. Make sure it is equal to zero


  • push all riders to zero
  • use adjustment knob if needed.

3. Never switch pans


4. Pick up the balance by red bar ONLY!!!

5. Don't zero balance when done.



Box Questions

1. It releases a gas and helps things rise.


  • bread, cake, cookies, etc.


2. A, B, C

  • A- Binoculars, glasses, telescope.
  • B- Glasses, magnifying glass, etc.
  • C- Thermometer


3. 50 cm^3


4. Rectangle A is wider.


5. 7 cm^3.


6. A,B,C

  • 8 cubes
  • 27 cubes
  • 8 cm^3, 27 cm^3


7. Second one.


8. The higher you go the surface gets wider.


9. A,B.

  • A- 1.2 cm and 3.8 cm
  • B- 1.65 cm, 2.52 cm, and 4.50 cm.
  • It will be more accurate.


10. .1 cm and .2 cm.


11. A,B

  • A- 40 cm^3
  • B- 1.3 cm^3


12. No they don't.


13. The lines are further apart because there's more depth or height due to lack of surface.