Study Guide for Quiz #1

'Tis a Study Guide

Lab Safety

Every Lab:

1. You must always have goggles over your eyes

2. Report all spills to Mr. Leeds immediately

3. Use Common Sense, Thomas Paine!


Nurse:

ext: 2828


Safety equipment in classroom:

1. Fire extinguisher

2. Fire blanket

3. Eye wash/shower


Chemicals:

1. Never taste chemicals

2. Always waft liquids to detect odor (no wafting solids or powders)

3. Avoid touching chemicals

4. Always wash hands with soap and water after lab

5. If chemicals touch skin: flush skin with water for 1 minute and notify Mr. Leeds


Glass:

1. Hot glass and cold glass look the same

2. Never use chipped or broken glass (tell Mr. Leeds of broken glass and throw it away)

3. Never use force to remove or insert glass


Alcohol Burners:

1. Roll up sleeves, put up long hair, not jus pull back (or you cannot do the lab)

2. Never walk away from a lit burner (a book inferno... get it?)

3. Never point the open end of a hot test tube at yourself or someone else

4. Do not look down into a test tube/beaker while it is being heated

5. Make sure burner is capped and flame is out when done


End of Experiment:

1. Clean-up area and materials completely (you will lose points)

2. Make certain that burner is out if one was used

3. Keep goggles on (over eyes) until Mr. Leeds says to put them away





Reaction in a Bag

Overview:

The purpose of the REaction in a BAg was to record observations that occur when multiple chemical substances are combined.


Reactions:

1. When calcium chloride (substance A) mixes with a liquid, it produces and exothermic reaction (bag gets hot)


2. When sodium bicarbonate (substance B) mixes with a liquid, it creates an endothermic reaction (bag gets colder)


3. When both the solids plus a liquid are mixed, it produces a gas.


Phenol Red (Red Liquid):

1. used as a ph indicator

2. below 7 turns yellow

3. Above 8 turns pink


Calcium Chloride (substance A):

1. Acidic

2. Hydrotropic (absorbs water)

Uses: - Canned Vegetables (keeps than from getting mushy)

- Elecrolyte in sports drinks

- Flavors pickles (salty)

3. Exothermic


Sodium Bicarbonate (substance B)

1. Not acidic

2. Endothermic

Uses: Baking, cleaning, and toothpaste







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Heating Baking Soda

Overview:


The purpose of the heating baking soda lab was to find out what happened if baking soda were to be heated.


What Happens When B. Soda is Heated?

If baking soda is heated, the substance changes and breaks down into other different substances.


Condensation at top of T. Tube:

The condensation comes from hot gas touching cooler surface of top of t. tube --> turns back into a liquid.


Gases:

The gas that was produced came from the baking soda when it was heated.


Tea Experiment:

When placing the heated and unheated baking soda into two separate tubes of tea, you can tell that they are different substances. You know this because when mixing the tea, the tea becomes a different color than the other one.


Control Group: unheated t. tube


Experimental group: heated t. tube


Indicator: tea (heated one is not baking soda)


Variable: Something you try to measure


Independent variable: causes a change in the dependent... the temperature


Dependent variable: color of tea


Control Factors:

1. Same type of tea

2. Same amount of b. soda

3. Same amount of tea

4. Same stirring time

5. Same sized t. tube


Experimental Errors:

1. Hole in the tubing, won't see the bottle fill with gas

2. Stopper is not tight (same reason as number 1)

3. Contaminated stirring rod, would have contaminated the tea


There has to be less (or equal to) amount of condensation in the test tube. You know this because the condensation comes from the baking soda; it is virtually impossible for it to produce more than itself.


Why is Baking Soda used in cooking?

When heated, it releases a gas which helps batter to rise

1.2 Volume Notes

Unit of measuremnt is cubic centimeters



Volume= length x width x height


Standard unit of volume= meter (m)


Unit Cube- a small cube 1 cm on each edge


Volume of liquids:

- use a graduated cylinder to measure volume (always check the intervals of scale)

- units= milliliters (mL) or cubic centimeters (1mL=1 cubic centimeter)

- Read from bottom of the meniscus


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1.3 Single Pan Balance

1. Check that the pan is clean and dry

2. Always zero balance before each massing

- push all riders to 0

- use adjustment knob if needed

3. Never switch pans

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