Quiz #1 Study Guide
Mr. Leed's First Quiz
Wednesday, Sep. 18th 2013 at 1:45pm
2700 Saint Andrews Boulevard
Boca Raton, FL
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.
- 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.
Reaction in a Bag
- To record the observations that occur when multiple chemical substances are combined and to use my observations to understand the reactions of the chemicals
- Phenol Red
- Used as pH indicator
- Calcium chloride
- mildly acidic
- Absorbs water (hydrotropic)
- Uses: canned vegetables (keeps them from getting mushy), electrolytes in sports drinks, and flavors pickles (salty flavor)
- Sodium bicarbonate (baking soda)
- not acidic
- Uses: baking, toothpaste, laundry detergent, cat litter
- Hole in the bag- if this occurred we would not know a gas was produced inside the bag.
- 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
- To observe and record the reaction that occurs when baking soda is heated.
- 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.
- 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
- 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.
- 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
- 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.
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.