Exam study guide
study guide
Lab saftey notes
- Nurse # is 2828 in case of emergency
- Always wear goggles and an apron during a lab
- If a chemical spills and/or gets on someone, tell Mr. Leeds
Safety equipment in the classroom:
- Fire extinguisher
- Fire blanket
- Eye wash/eye shower
- Never taste the chemicals
- Waft liquids to detect odor but don't waft solids or powders
- Avoid touching chemicals
- Always wash hands with soap and water after lab
- If chemicals touch skin: flush skin with water for 1 min AND notify Mr. Leeds
- Hot and cold glass look the same
- Never use chipped/broken glass and tell Mr. Leeds and dispose of broken glass properly
- Never use force to remove or insert glass
- Roll up sleeves, pull up long hair (in a bun)
- Never walk away from a lit burner
- Never point the open end of a hot end of a test tube at yourself or anyone else
- Do not look down on test tube while it's being heated
- Make sure burner is capped and flame is out when done
- CLEAN UP AREA AND MATERIALS COMPLETELY! (or you lose points) and make sure burner is out if one was used
- Keep goggles over your eyes unless Mr. Leeds says to put them away
Labs
Reaction in a bag lab
-acidic and attracted to water
-used in canned vegies (keeps from getting mushy) electrolyte, and sports drinks
Chemical B: Sodium bicarbonate (baking soda)
-not acidic
-uses are making volcanoes, baking, laundy detergent, brushing teeth, and cleaners
Red Liquid: Phenol red
-used as an indicator
-below 7 turns yellow and above 8 turns pink
Procedure
The purpose of the lab was to record the observations that occur when multiple chemical substances are combined to use my observations to understand the reactions of chemicals.
Conclusion
The purpose of the reaction in a bag lab was to record the observations that occur when multiple chemical substances are combined to use my observations to understand the reactions of chemicals. During the lab we mixed chemical A, chemical B, and red liquid in to a plastic bag. The liquid turned yellow and the bag started to expand. The mixture’s temperature was hot. After that we got a specific formula to test out and ours was A + red liquid. The mixture started to turn purple and it was very hot. I have come to the conclusion that when we mix the chemicals they change temperature, color and produce gas. I’ve come to this conclusion because during the lab the data has showed that if you mix A, B and red together the temperature rises, turns yellow, and produces gas.
Heating Baking Soda
To observe and record the reaction that occurs when baking soda is heated.
Conclusion
The purpose of this lab was to observe and record the reaction that occurs when baking soda is heated. While heating the baking soda nothing much happened except gas left the baking soda and water appeared at the top of the beaker. When the tea was added to the heated baking soda and the non-heated baking soda it showed that both substances aren’t the same. They aren’t the same because gas left the heated baking soda. I have come to the conclusion that if you heat baking soda all of the gas will leave the baking soda.
Experimental errors
One example of an experimental error could have been if someone did not rinse off the stirring rod when stirring from tube to tube. Another error could have been the tea had some sort of chemical in it, which could have changed the reaction of the baking soda.
Post lab
-Gas comes from the baking soda
-Control group- unheated baking soda is the control group
-Experimental group- heated baking soda
Notes
Volume of liquids
-READ FROM THE BOTTOM OF THE MENISCUS
-use graduated cylinders to measure volume and always check intervals or scale units= milliliters (ml) or centimeters cm cubed
Single Pan balance notes
-Never switch pans
-Pick up by red bar only
-Don't zero balance when done
mass, volume, and density notes
Mass and volume
1. objects that are made of the same substance that have the same volume, will have the same mass (regardless of their shape)
2. The mass of an object will double if its volume doubles
3. Objects that have the same volume but are made of different substances will not have the same mass
Density
Mass over volume= density
Aluminum density is always 2.7 g/cm3
Extra notes
- The chemical name for Epsom salt is Magnesium sulfate
- When the volume increases the density decreases
TESTS
Chapter one
- Transferring kg to lb divide by 2.2
Measuring by Displacement of water experiment
-Mr. Leeds gave each group different amount of sand because each group gets 40% of air space.
Chapter 2
Error: There could be a hole in the sheet or the sheet isn't tight enough
Explanation: the gas could escape
Ice and water lab:
Error: Condensation forms on the outside of the bottle
Explanation: If someone wiped off the condensation which would cause a decrease in mass
Chapter 3
Mi-Mf is the mass of the gass but Mf-Mi is the change in mass