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Tuesday, December 11, 2007
Tues Dec 11
SCH 3U Period 1 and 4 Solubility Curves Revisited Combined molarity solutions pOH Review TEST TOMORROW FORMAL LAB due Thursday Overview due Friday
SNC 1P Computer Lab - Type Good Copy of Electric Shock News Report Blackout Reading + Q's
Water is referred to as the "universal solvent" because a.Water molecules are small in size. b.Water molecules are highly polar. c.Water molecules form hydrogen bonds. d.a, b, and c only e.a and c only
Ms Wiens, i was wondering since question 7 on the discussion was to list all possible errors in the lab if we even had to do a sources of error? Like, if we answer question 7 and list all the possible errors, wouldnt it be the same as writing the sources of error? Thanks alot!
Ms wiens for Q1 in analysis, you know how it says to find the average. What if you did only two trials and the results are not within +or- 0.2mL. for one trial i got level 4 so should i use that amount or do i still have to average them? thank you.
miss wiens I got a level 3+ twice and a level 4. The two level 3+'s are cloest to each other, but since the level 4 is more accurate should i use it and the one cloest to it for my average?
The levels are not related to your volumes (they should be, but likely are not due to error on your part). Do not determine which volumes are most accurate based on the levels for your end points.
Ms Wiens, for question 5 isnt density= m/v? and since it is what is the point of question 5. We already know the mass of the acetic acid, it is in question 4. Soo are we supposed to make then the volumes 60 mL (50ml of water and 10ml of vinegar) or 60ml+the avg.volume found in question 1 to solve for mass?
Mass Percent is = mass of solute/mass of solution x 100%
Not the same thing.
You are finding the concentration of the acetic acid in the vinegar (vinegar is not pure acetic acid), you then later find what percent by mass is the acetic acid in vinegar.
You are finding these values in relation to the vinegar I provided.
THINK - you were to add approx 50 mL of water and yet you have learned that exact volume is critical for solution stoichiometry.
12 comments:
Water is referred to as the "universal solvent" because
a.Water molecules are small in size.
b.Water molecules are highly polar.
c.Water molecules form hydrogen bonds.
d.a, b, and c only
e.a and c only
The contamination of Walkerton, Ontario's water supply in 2000 was caused by
a. lead
b. E. coli bacteria
c. mercury
d. nitrates
e. pesticides
Ms Wiens, i was wondering since question 7 on the discussion was to list all possible errors in the lab if we even had to do a sources of error? Like, if we answer question 7 and list all the possible errors, wouldnt it be the same as writing the sources of error? Thanks alot!
Yes, Q 7 already covers sources of errors - they are the same thing.
Ms wiens for Q1 in analysis, you know how it says to find the average. What if you did only two trials and the results are not within +or- 0.2mL. for one trial i got level 4 so should i use that amount or do i still have to average them? thank you.
miss wiens I got a level 3+ twice and a level 4. The two level 3+'s are cloest to each other, but since the level 4 is more accurate should i use it and the one cloest to it for my average?
ms can you explain me Q# 4,5
The levels are not related to your volumes (they should be, but likely are not due to error on your part). Do not determine which volumes are most accurate based on the levels for your end points.
Ms Wiens, for question 5 isnt
density= m/v? and since it is what is the point of question 5. We already know the mass of the acetic acid, it is in question 4. Soo are we supposed to make then the volumes 60 mL (50ml of water and 10ml of vinegar) or 60ml+the avg.volume found in question 1 to solve for mass?
and a future thanks for clearing this up.
yo guys r stupid why you guys doing your lab on the last day.
wow
Density is mass/volume
Mass Percent is = mass of solute/mass of solution x 100%
Not the same thing.
You are finding the concentration of the acetic acid in the vinegar (vinegar is not pure acetic acid), you then later find what percent by mass is the acetic acid in vinegar.
You are finding these values in relation to the vinegar I provided.
THINK - you were to add approx 50 mL of water and yet you have learned that exact volume is critical for solution stoichiometry.
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