Study Guide #1
- goggles must be kept OVER YOUR EYES until Mr. Leeds says to put them away *even if you are already finished and cleaned up*
- Report all accidents/ spills to Mr. Leeds immediately
- Try your best to use common sense
- Nurse: ext: 2828
Safety Equipment in Classroom:
- Fire extinguisher
- Fire blanket - put out a fire
- Eye wash/ shower
- Never taste chemicals (even if they look yummy!)
- Always WAFT liquids to detect odor
- NEVER WAFT SOLIDS/ POWDERS!
- Avoid touching chemicals
- Always wash hands with soap and water after lab
- If chemicals touch skin: flush skin with water (for 1 minute) AND notify Mr. Leeds
- Hot glass and cold glass look the same
- Never used chipped or broken glass - tell Mr. Leeds and dispose of broken glass in proper trash
- Never use force to remove or insert glass
- Roll up sleeves, put UP long hair, NOT just pulled back (or you cannot do lab)
- Never walk away from a lit burner
- Never point the open end of a hot test tube at yourself or someone else
- Do not look down into a test tube/ beaker while it is being heated
- Make sure burner is capped and flame is out when done because fire needs oxygen
End of Experiment:
- CLEAN-UP AREA & MATERIALS COMPLETELY!!!! (Or you LOSE points)
- Make certain that burner is out if one was used
- Keep goggles on (over eyes) until Mr. Leeds says to put them away
Reaction in a Bag Lab
- Phenol Red
- Used as a pH indicator - measures acidity
- Below 7 turns yellow
- Above 8 turns pink
- measures acidity
- goes from 0-14
- 0 - Acid 7 - Neutral 14 - Alkaline
- The lower the number the more acidic
- Acid - Lemon juice 1.5, Citric Acid
- Alkaline - Tums 10, Anti-acid
- Calcium chloride (calcium and chlorine)
- Hydrotropic - absorbs water (attracted to water) hydro - water, tropic - loves
- Hydrophobic - opposite hydro - water, phobic - afraid
- Most salts are hydrotropic
- Sodium bicarbonate (baking soda)
- Baking soda is salty - hydrotropic
- Not acidic
- Uses: baking, toothpaste, laundry detergent
The purpose of the Reaction in a Bag lab was to record the observations that occur when multiple chemical substances are combined and to use my observations to understand the reactions of the chemicals. My partner and I mixed two chemicals with the red liquid. We observed what happened and saw the chemicals dissolve into a yellow, foaming liquid with some pink in the corner. Though the pink stayed cold, the yellow liquid turned hot. The bag began to fill with gas as the yellow disappeared. I have come to this conclusion that when you mix red liquid or water with substance A heat is produced, an exothermic reaction, and gas is produced when substances A and B and the red liquid mix.
Heating Baking Soda Lab
1. Nothing (could condense and get smaller and more dense)
2. moisture, misty, foggy, condensation, water droplets
3. water was emptying (being pushed) out of the bottle into the container
4. gas that was filling the bottle came from the baking soda
5. gas from the baking soda hits cooler stopper (water cycle - when water vapor hits something cooler, it turns to a liquid)
6. heated one - darker, heated one - dissolves, not heated one - does not dissolve
7. No they are different because the unheated is only baking soda plus tea, so the heated should be the same color.
control group (we could control it) - unheated baking soda and tea
experimental group (experimented with it) - heated baking soda and tea
indicator: tea (shoed that the heated test tube is not baking soda anymore)
variables: a category you try to measure ex. temperature - burner, flame (heat)
independent variable: causes a change in the dependent variable ex. tea color
dependent variable: depends on the independent variable
control factors: things that we can control
- using same type of tea for each test tube
- same amount of baking soda
- same amount of tea
- same size test tube
- same amount of stirring time
- hole in tubing - won't see gas fill the bottle/ water pushed out
- stopper is not snug - won't see gas fill the bottle/ water pushed out
- not cleaning stirring rod - contaminate
Is the amount of condensation that forms at the top of the heated test tube more or less than the amount of baking soda being heated? Explain your answer.
Less (or same), because the condensation comes from baking soda and it cannot produce more than itself.
The purpose of the Heating Baking Soda Lab was to observe and record the reaction that occurs when baking soda is heated. After the apparatus was set-up, we lit the burner. The baking soda releases a gas. It goes through the test tube and into the bottle. In the second part of the lab, we filled another test tube with baking soda and added tea to both until they were ¼ filled. They are honey colored or orange. The heated test tube is darker in color. I have come to the conclusion that when you heat baking soda gas separates from the baking soda, leaving a substance that is no longer baking soda. I have come to this conclusion because during the lab I observed the test tube getting misty. Also, the gas traveled through the tubing and into the inverted bottle, which caused the water to evaporate. This means that the baking soda emits a gas.
1.2 Volume Notes
- unit of measurement: cm3 (cubic centimeters)
- Volume= l x w x h (a x b x c)
- Standard unti of length = meter (m)
- 1 centimeter ( centi - 100) (1 cm) = 0.1 m 100 cm = 1 m
- unit cube - a small cube 1 cm on each edge
- use a graduated cylinder to measure volume
- *Always chef the intervals or scale
- Units = milliliters (mL) OR cm3 1 mL= 1 cm3
Singel Pan Balance Notes
- Check that pan is clean and dry
- Always "zero" balance before EACH massing
- push all riders to zero (left)
- Use adjustment knob if needed
4. Pick up balance by red bar only
5. Don't zero balance when done
The baking soda releases gas when heated, so it helps batter rise. (ex. bread, cookies, cupcakes, etc.)
3. How many cubic centimeters of water are required to fill a graduated cylinder to the 50.0-mL mark?
4. Rectangular box A has a greater volume than rectangular box B but the length of box A is less than the length of Box B. How is this possible?
Box A has a bigger width or height than Box B.
5. Adding a stone to a graduated cylinder containing 25.0 cm3 of water raises the water level in the cylinder to the 32.0-cm3 mark. What is the volume of the stone?
6. A student has a large number of cubes that measure 1 cm along each edge. (If you find it helpful, use a drawing or a set of cubes to answer the following questions.)
a. How many cubes will be needed to build a cube that measures 2 cm along each edge?
b. How many cubes will be needed to build a cube that measures 3 cm along each edge?
c. What is the volume, in cubic centimeters, of each of the cubes in (a) and (b)?
8 cm3, 27 cm3
7. One rectangular box is 30 cm long, 15 cm wide, and 10 cm deep. A second rectangular box is 25 cm long, 16 cm wide and 15 cm deep. Which box has the larger volume?
8. Figure A shows a cone-shaped graduate used for measuring the volume of liquids. Why are the divisions not equally spaced?
As the surface increases, the depth decreases.
9. a. 1) 1.2 2) 3.7, No
b. 3) 1.65 4) 2.52 5) 4.51, No
c. It will be more accurate.
10. What does each cylinder's marks go by?
11. How much liquid?
a. 40 cm3
b. 1.3 cm3
12. Where did they estimate from for each measurement?
12: 11.5-12.4 12.0: 11.95-12.04 12.00: 11.995-12.004
13. The lines are further apart because there is more depth/ height due to lack of surface.