Quiz #1 Study Guide

Ben Milstein

Mr. Leed's First Quiz

Wednesday, Sep. 18th 2013 at 1:45pm

2700 Saint Andrews Boulevard

Boca Raton, FL

Lab Safety

The Basics

  • Test the odors of liquid by wafting them under nose.
  • Tell Mr. Leeds if something breaks.
  • Never use force to remove or insert glass.
  • Must keep goggles on until Mr. Leeds says to remove them.
  • 2828 is nurse extension.

The Ok's

  • You should never throw broken glass into the regular trash.
  • If you get any chemicals on your skin you should flush your skin with water and tell Mr. Leeds.


The Do Nots

  • Do not report all accidents to Mr. Leeds at the end of class; report them to him immediately.
  • Do not take your glasses off as soon as you finish the lab; wait until Mr. Leeds allows and instructs you to take them off.
  • Hot glass does NOT look different than cold glass; they look identical.
  • Do not use a cracked test tube; if there is a crack report it to Mr. Leeds and he will take care of it.
  • The emergency blanket is not for games; it is to only be used if someone is on fire.
  • Do not put your goggles on your forehead when you clean up; others are still working.


Tips

  • Three important safety tips when working with an alcohol burner are: put up hair, pull up sleeves, and never leave the burner unattended.
  • Three safety precautions when using chemicals: flush your skin with soap and water for 1 minute and tell Mr. Leeds if the chemicals get on your skin, always waft liquid chemicals, and do not waft a solid or powder substance.


Emergency Equipment

Balance Notes

  1. Check that the pan is clean and dry.
  2. Always "zero" balance before each massing- push all riders to zero (left), use adjustment knob if needed.
  3. NEVER switch pans.
  4. Pick up balance by red bar only.
  5. Don't zero balance when done.


Reaction in a Bag

Post-Lab

Purpose


  • To record the observations that occur when multiple chemical substances are combined and to use my observations to understand the reactions of the chemicals

Red Liquid



  • Phenol Red
  • Used as pH indicator

Solid A



  • Calcium chloride
  • mildly acidic
  • Absorbs water (hydrotropic)
  • Uses: canned vegetables (keeps them from getting mushy), electrolytes in sports drinks, and flavors pickles (salty flavor)

Solid B



  • Sodium bicarbonate (baking soda)
  • not acidic
  • Uses: baking, toothpaste, laundry detergent, cat litter

Experimental Errors

  • Hole in the bag- if this occurred we would not know a gas was produced inside the bag.

Reaction


  • When Substance A was mixed with a liquid, the bag was hot because there was an Exothermic Reaction
  • When Substance B was mixed with a liquid, the bag was cold because there was an Endothermic Reaction
  • When Substance A and Substance B were mixed with a liquid, the mixture created a gas, which is why the bag inflated.



Heating Baking Soda

Post-Lab

Purpose


  • To observe and record the reaction that occurs when baking soda is heated.

Condensation

  • Comes from hot gas touching cooler top of test tube. Turns it back into liquid.
  • Gas comes from heating baking soda.

Heated and Non-heated Cylinder

  • Must contain different substances than each other because there was a color difference.

Groups

  • Control Group: unheated tube
  • Experimental Group: heated tube
  • Indicator: tea (shows heated test tube is not only made of baking soda)

Variable- something you try to measure

  • Independent Variable (causes change in dependent variable): temperature (heat)
  • Dependent Variable: color of the tea

Control Factors:

  • Same type of tea, same amount of tea, same amount of baking soda, same temperature, stirring tubes in same amount of time, same size test tube.

Experimental Errors:

  • Hole in tubing- won't see bottle fill with gas
  • Stopper not snug- won't see bottle fill with gas
  • Stirring rod not clean at beginning- contaminate

Reaction

  • The baking soda emitted a gas when heated and the condensation created from the heat of the burner traveled through the tubing in gas form. The small gas bubbles traveled into the bottle and released their gas which took up space in the bottle; this explains the water traveling out of the bottle and into the container.

Volume

Volume Notes

  • Unit of measurement: cubic centimeters
  • Volume= length x width x height
  • Standard unit of length= meter (m)

Volume of Liquids

  • Use a graduated cylinder to measure volume
  • *Always check intervals or scale
  • Units= millimeters (mL) OR cubic centimeters
  • Read from bottom of meniscus.

Box Questions

1. Baking soda is used in baking because when heated, it releases a gas and that helps dough/batter to rise.

3. 50 cubic centimeters of water.

4. Rectangle A has a bigger height or width.

5. 7 cubic centimeters.

6. a. 8 cubes

6. b. 27 cubes

6. c. 8 cubic centimeters and 27 cubic centimeters

7. Box 2

8. The more surface the less depth there is. The less surface the more depth there is.

9. a. Arrow 1= 1.2

9. a. Arrow 2= 3.8; we cannot estimate to the hundredths because we can only estimate one more measurement than what is shown.

9. b. Arrow 3- 1.65

9. b. Arrow 4= 2.52

9. b. Arrow 5= 4.00 ; we cannot estimate to the thousandths because we can only estimate one more measurement than what is shown.

9. c. The second ruler goes up to 0.01 cm, so we are allowed to go only one more measurement further; more accurate.

10. Cylinder A goes by 0.1 and Cylinder B goes by 0.2.

11. Cylinder A= 4.0 cubic centimeters.

11. Cylinder B= 1.3 cubic centimeters.

12. 12 cm: 11.5-12.4

12. 12.0 cm: 11.95-12.04

12. 12.00 cm: 11.995-12.004

13. You can measure amounts in between two numbers with a thin graduated cylinder without having to estimate and not with a wide graduated cylinder.