Science Quiz #1

Emily Perelman

Lab Safety

Will do 33-37 labs

Every Lab

  • Goggles must be kept over your eyes until Mr. Leeds says to put them away (33 labs or so)
  • Report all accidentals/spills to Mr. Leeds immediately
  • Try your best to use common sense

In Case of Emergency

  • Nurse ext. 2828

Safety equipment

  • Fire extinguisher
  • Fire blanket – wrap around someone to extinguish flames (covered in fire proof chemicals
  • Eyewash/shower

Chemicals

  • Never taste chemicals
  • Always waft liquids to detect odor
  • Never waft solids/powders
  • Avoid touching chemicals
  • Always wash hands with soap + water after lab
  • If chemicals touch skin: flush skin with water for one minute + notify Mr. Leeds

Glass

  • Hot glass + cold glass look the same
  • Never use chipped or broken glass

o Tell Mr. Leeds and dispose in proper trash

  • Never use force to remove or insert glass

Alcohol burners

  • Roll up sleeves, put up long hair (not just put back) (or you cannot do lab)
  • Never walk away from a lit burner
  • Never point the open end of a hot test tube or lit burner at yourself or someone else
  • Do not look down into a test tube/beaker while its being heated
  • Make sure burner is capped and flame is out when done

End of experiment

· Clean up area + materials completely (or you lose points)

· Make sure burner is out if one was used

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


Scholar Reaction In The Bag Inquiry Demonstration and Lab Activity

Reaction in a Bag Lab

Gas comes from – a + b +liquid

Heat comes from – a + a liquid (exothermic reaction)

  • Endothermic reaction – heat comes from inside


Experimental Errors

  • If there was a hole in the bag: would not see gas being produced


Red Liquid

  • Phenol red
  • Used as a pH indicator
  • Below 7 on pH scale turns yellow
  • Above 8 on pH scale turns pink


pH scale

  • Measures acidity
  • Goes from 0-14
  • 0 (acid) - 7(neutral) - 14(alkaline)
  • Examples:
  • Lemon juice – 1.5 on pH scale (acidic)
  • Tums – 10 on pH scale (alkaline)


The Two Solids

Solid A – calcium chloride (calcium + chlorine)

  • Acidic
  • Hydrotropic (Hydro = water)
  • Absorbs (attracted to) water
  • Used in: Canned veggies, gatorade, flavor pickles, a preservative
  • Absorbs the water (Hydrotropic)
  • Can stay on shelf for a long time
  • Keeps them firm (absorbs water)
  • Not soggy/mushy
  • Calcium chloride is an electrolyte (used in sports drinks)
  • Salty flavor

Solid B – sodium bicarbonate (baking soda)

  • Used in baking (cupcakes + cookies etc.) - helps rise
  • Absorbs moisture + fridge odor
  • A little hydrotropic (most salts are)
  • Also used in: toothpaste, laundry detergent
  • Non acidic (alkaline)



Heating Baking Soda Lab


Blue dot questions

#1. Bottom of the test tube

  • See brown (test tube getting burned/scorched)
  • Baking soda stays fairly the same
  • Becomes a little more compacted

#2. Top of the test tube

  • Condensation forming (moisture)
  • Bubbly
  • Misty/foggy/wet

#3. Occurring in the inverted bottle

  • Water level decreases: goes into container (pushed out)
  • This is why it was important to fill container with water ONLY to line or it would get pushed out

#4. Heating empty test tube (in lab)

  • No condensation occurs
  • Bottle doesn’t fill with gas (like it does when baking soda is heated)
  • Therefore the gas comes from the baking soda (hot gas)

#5. Where does gas come from

  • Baking soda

#6. Where do the droplets come from

  • The gas from the baking soda makes droplets/condensation
  • Water DID NOT come from bottle into test tube
  • Some gas did not make it too the bottle
  • Hits the top of the test tube, which is cooler than the bottom (where it came from) and makes condensation
  • The temperature change makes condensation

TEA PART

Heated baking soda with tea

  • Baking soda dissolves
  • Usually when heated = darker
  • Translucent yellowy brown

Not heated baking soda

  • Baking soda condenses at the bottom
  • Murky
  • Off-orange

#7. Are 2 white powders the same substance

  • No
  • Must be different because if the heated substance were the same as the non-heated baking soda they would look the same when the tea was added.
  • The two change to different colours when tea is added


Science Terms

Control Group – controlled the outcome of it Unheated baking soda with tea

Experimental Group – experimented with the outcome (not fully controlled)

  • Heated baking soda with tea

Indicator – shows us something

  • The tea
  • Showed us the heated test tube was not baking soda (a change had occurred)

Variables – a category you try to measure in

Independent variable – something that causes a change in the dependent

  • Heat/flame/burner

Dependent variable – depends on independent

  • Tea color

Control factors – things we control in the lab

  • Same type of tea
  • Same amount of baking soda
  • Same amount of tea
  • Same size test tube
  • Same amount of stirring time

Experimental Errors

1) Hole in tubing: gas wouldn’t make it to the bottle (gas wouldn’t push out water)

2) Stopper is not snug: the amount of condensation would not occur (gas escape)

3) Stirring rod not rinsed off: contaminate sample

Extra Questions

I. Is the amount of condensation more or less than the amount of baking soda that’s being heated

  • LESS or the same
  • Gas making condensation is from the baking soda
  • Cannot produce more gas (that makes condensation) than itself


Lab 1.1 Heating Baking Soda

Volume Notes

Unit of measurement: cm3 (cubic centimeters)

Formula for volume: l x w x h (a x b x c)

Standard unit of length: meter (m)

One centimeter (1cm) = 0.01m

100cm = 1m

Unit cube: small cube, 1cm on each side (volume = 1cm3)


Volume of Liquids

  • Use graduated cylinder to measure
  • *ALWAYS check intervals of scale
  • Unit: milliliters (mL) or cm3
  • 1mL = 1cm3


Single Pan Balances

1) Check that the pan is clean and dry

2) Always “zero” the balance before each massing

a. Push all riders to 0 (left)

b. Use adjustment knob is needed

3) Never switch pans

4) Pick up balance by red bar only

5) Don’t zero balance when done


Box Questions

1) Why is baking soda used in baking?


  • When heated it releases a gas that helps things rise (dough/batter)
  • cookies, cakes, bread, cupcakes


3) 50cm^3 are required to fill a graduated cylinder to the 50 mL mark


4) If rectangular box A is 30cm tall and the length is 5cm it will have a greater volume than box b if box B is 10cm tall and the length is 6cm.


5) From displacement we know the volume of the stone is 7cm^3


6) a) 8 cubes b) 27 cubes c) the volumes of the previous would be 8cm^3 and 27^3


7) if the volumes are 55cm^3 and 56cm^3 the second box has the greater volume


8) the cone and is not equally spaced measurements because the sides go slanted upwards. The division are not equally spaced because since the surface area gets bigger towards the top of the cone the measurements are spaced smaller together as opposed to the test tube where the lack of surface area makes even measurement marks all the way up.


9a) Arrow I is about 1.2 cm and Arrow II is about 3.7 cm

9b) Arrow III is about 1.64 cm and Arrow IV is about 2.52 cm. Arrow V is about 2.51 cm

9c) you should report the positions to the nearest 0.01 cm because 0.1cm is given so it is easier to find them than in figure b(a)


10) the cylinder goes up by 0.1cm^3, and the next cylinder goes up by o.2 cm^3


11) the level of the liquid in figure d (a) is 4.0 cm^3, the level of the liquid in figure d (b) is 1.25 cm^3


12) 12 cm - round down from 12.4 and up from 11.5

12.0 - round down from 11.95 and up from 12.04

12.00 - round down from,11.995 and up from 12.004


13) Lines are more spaced out and easier to read when the graduate is narrow or tall because it makes up for the lack of surface area the narrow and tall tube possesses because the other ones measurements would be very close together and harder to read due to the amount of surface area.