Study Guide for Quiz #1

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Reaction in a Bag Lab

Purpose: to record the observations which occur when multiple chemical substances are combined and use our observations to understand the reactions of the chemicals.



Red liquid = Phenol Red


- used as a pH indicator


pH scale: measures acidity

- bellow 7 turns yellow (acid)

- above 7 turns pink (alkaline)

- 7 = neutral

Ex:

- lemon juice = 1.5

- tums = 10


Solid A = calcium chloride

- calcium + chlorine

- mildly acidic

- hydro-tropic (attracted to water)

Uses: sports drinks, flavors pickles (salty flavor), canned vegetables (keeps them from getting mushy)


Solid B = sodium bicarbonate (baking soda)

- not acidic

Uses: baking, cat litter, tooth paste, laundry detergent


Red liquid + A + B = Gas

A + liquid = hot (exothermic reaction)

B + liquid = cold (endothermic reaction)

Heating Baking Soda Lab

Purpose: to observe and record the reaction that occurs when baking soda is heated.


- the gas came from the baking soda


- the droplets evaporated from the baking soda

- the heated substance is not baking soda

- it is a darker orange when mixed with tea

- it clumps when mixed with tea

- there is less condensation that the heated baking soda because it cannot produce more of something than it has


Experimental Group: heated baking soda

Control Group: unheated baking soda

Indicator: tea

Variable: something you try to measure

- Independent (flame) will cause change in

- Dependent (color of the tea)

Control Factors: things in the lab that you control that would affect the outcome

Ex: same type of tea, amount of baking soda, amount of tea, stir for same amount of time, same size test tube

Volume

Unit of measurement: cm^3


Unit cube: 1 cm on each side

Volume = lwh (book uses abc)

Metric System:

1cm = 0.1m or 100cm = 1m

mL = milliliters = 1cm^3

Graduated Cylinders:
- always check intervals

- read from the bottom of the meniscus

Single Pan Balances

1. check that pan is clean and dry


2. always zero balance between massing

- push all riders to zero

- use adjustment knob if needed

3. NEVER switch pans

4. pick up balance by red bar only

5. don't zero balance when done


Box Questions

1&2 pg. 5

1. Why do you think baking soda is used in baking? It releases gas when heated which helps dough/batter rise/get fluffy.


2. X


3-8 pg. 8

3. 50.0

4. the height and/or width is larger

5. 7cm^3

6.

a. 8

b. 27

c. a = 8cm^3, b = 27cm^3

7. the second box

8. because the cone gets wider as it goes up


9-13 pg. 11&12

9.

a. 1.2, 3.7, no

b. 1.65, 2.51, no

c. because it is more accurate

10.

a. 0.1cm^3

b. 0.2cm^3

11.

a. 4.0 mL

b. 1.26 mL

12.

11.5 - 12.4

11.95 - 12.04

11.995 - 12.004

13. they can be measured more accurately because the lines are further apart because there is more depth

Lab Safety

For Every Lab

- Always wear goggles until Mr. Leeds says to put them away (even if


you are done)

- report ALL accidents/spills to Mr. Leeds immediately

- nurse ext: 2828


Safety Equipment in classroom

- fire extinguisher

- fire blanket

- eye wash/shower


Chemicals

- never taster chemicals

- always WAFT liquids to detect order

- NEVER waft solids or powders

- always wash hands after the lab

- avoid touching chemicals

- if chemicals touch skin, flush 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 insert or remove glass


Alcohol Burners

- roll up sleeves, put up long hair (not just pull back)

- never walk away from a lit burner

- never point the open end op a hot test tube at yourself or someone else

- do not look down a test tube/beaker while it is being heated

- make sure burner is capped and flame is out when done


End of Experiment

- CLEAN-UP AREA AND MATERIALS COMPLETELY!!!!!

- make certain that the burner is out (if one was used)

- keep goggles on (over eyes) until Mr. Leeds says to put them away.