HONORS CHEMISTRY – Hey guys, here’s a pic of some “high density” koi that I saw in Hawaii (at the Dole Pineapple Plantation, of all places!). Great job with the density problems – be sure and practice them tonight using the format I showed you in class today.
On a more practical side – and even better(!), can you now use what you’ve learned about density? Who is going to be your spokesperson? When is your lab going to be due? Do you need two due dates???
Can’t wait to “watch” you work!
Hon Chemistry 9-1-16 Density & ID of Unknown Lab from Tammy Skinner on Vimeo.
Application: Density can be applied in every day life and in other subjects. In daily life density can be seen in cities, traffic, shopping centers, restaurants, maps on the weather channel, etc. Density is everywhere if you look for it and can be useful to know in order to give accurate descriptions of places and things. Also, it is in other subjects such as world geography, where it is seen in different kinds of maps such as population maps.Knowing and understanding density can improve your knowledge and ability to read and make maps.
Struggle: I think I waited too long to get started on my THLab and my SI scavenger hunt. I should have given myself more time to work on each.
Triumph: I have done a good job keeping up with notes and also taking good notes. I have remembered to abbreviate so that I can also listen better after I finish note taking.
On the SI Lab, how do we find the exact freezing point of salt water? I assume we can’t google it since it says measure it.
K – I would kind of do a mini-experiment and actually work it out! 🙂
This week I would rate myself a 3/5. I am improving on my note-taking skills, while also listening to the discussion. I have worked on my SI Scavenger Hunt. I need to work on relaxing a little bit. This week was a little more stressful than usually for me because of my after school activities and trying to balance my time with my school work and that. I need to relax a little bit more, but not too much, because I still need to stay on top of things. It was overall a pretty good week!
I would rate myself 3 out of 5 stars. I understood all of the information on sig figs and the SI system; however, I did not keep up with the working out the problems. I know what to do but keep saying things wrong or making tiny mistakes. I also should have worked on the take home labs a little more.
Struggle: This week I feel like I struggled with the application of sig figs and also giving myself plenty of time to finish my labs without becoming stressed. I believe that reviewing over the rules and practicing example problems will help me become more familiar with sig figs. Next time, I plan on starting my labs a day or two ahead, so that I know what materials I need to gather instead of rushing to collect them at the last minute.
Triumph: I began studying for the SI quiz the weekend before the quiz, and I reviewed over them every night so that I did not have to cram at the last minute. Doing this made me feel confident about the quiz, so I did not worry about the quiz the morning before I took it.
Triumph: This week I was able to manage all the chemistry work without over stressing. I started studying a little bit early for the quiz, and worked on getting most of the measurements I needed for the SI scavenger hunt. Also, I was able to start on the take home lab and building my balance. By working hard a little bit every day, it helps me to procrastinate, but to do my best on every assignment with as little stress as possible.
Has anyone decided when the ID of Unknowns is due?
We haven’t set anything but I was thinking everyone should try to get their masses in by the end of this school week so we can compare!!
alrightie, thanks!
This week I would rate myself 3 out of 5 stars. I got a lot better at taking quick and efficient notes. I also was glad that I knew a lot of what we learned this week including sig figs and scientific notations. However, I keep making tiny mistakes such as making sure I use the correct number of sig figs in scientific notation and forgetting to put the negative sign next to the exponent whenever it is a small number. Hopefully I can fix that with a little practice though!
Hey Guys! I was going to post my density of the gray block, but my measurements are a little off so it was incorrect. I am going to check it, but I’m pretty sure my block (the gray) was Epsilon.
Hey friends! I just tried to calculate the density of my Black block but none of the densities on the table matched mine. I must be a little bit off. But if I had to choose a block name for the Black block then I would say Delta.
Hey guys! I think my measurements are off a bit but this is what I’ve got so far:
White block
Density: 0.505 g/cm^3
“name”: Alpha (this is the one closest to my measurement)
Here’s a thought – in all the time you’ve known me, have I EVER taken ANY answer without also seeing proper work?!?
Since we haven’t come up with a due date for this, or at least I don’t think we have, we could all have our individual work maybe due this Thursday or Friday, and then the lab write up could be due this Saturday or Sunday so that the person who is writing it up will have plenty of time.
I had a black block and my answer was closest to Delta.
V=l x w x h
M= 83.35 g
D= M/V
V= l x w x h
V= 8.85 cm x 3.80 cm x 2.70 cm
V= 90.801 cm3
D= M/V
D= 83.35g/ 90.801 cm3
D= 0.918 g/cm3
I had a milky white block, and my answer was closest to Delta.
M = 59.62 g
V = l x w x h
V = (6.59 cm) (2.57 cm) (3.92 cm)
V = 66.390 cm^3
D = M / V
D = (59.62 g) / (66.390 cm^3)
D = 0.898 g/cm^3
I had a clear block and my density was closest to Gamma, I’m no completely set on choosing Gamma.
Density = m/V
Mass = 59.44 g
Volume = l x w x h
V = l x w x h
V = 10.41 cm x 1.19 cm x 3.84 cm
V = 47.57 cm^3
D = m/V
D = 59.44 g / 47.57 cm^3
D = 1.249 g/cm^3
Answer: 1.25 g/cm^3
My answer is +0.08 from Gamma and is -0.17 from Epsilon so it’s kinda of close so I’m wondering what your guys feed back is going to be.
White Block:
Mass = 40.88 g
Volume = l x w x h
94.0 mm x 68.9 mm x 13.0 mm = 84195.8 mm^3
QS = QG x CF
x cm^3 = 84195.8 mm^3 x (1 cm^3 / 1000 mm^3)
x = 84.1958 cm^3
D = (m / V)
D = (40.88 g / 84.1958 cm^3)
D = 0.486 g/cm^3 <<<<<—–answer
It's the closest to Alpha, but I'm going to try to redo my work so I can be sure!
From my work, black is either Beta or Delta. I did it twice. First time using measurements from class and the second using a tracing I did of my block. The first result was 1.04 g/cm^3. so that would be closer to Beta. But the second time the result was 0.913 g/cm^3 so that’s closer to Delta. I think it’s probably Delta
Work:
first time:
V= l x w x h
V= (11.21 cm)(5.90 cm)(1.20 cm)
V= 79.4 cm^3
m= 82.49 g
D= m/V
D= (82.49 g)/ (82.49 cm^3)
D= 1.04 g/cm^3
second time:
V= (11.15 cm)(6.0 cm)(1.35 cm)
V= 90.32 cm^3
m=82.49 g
D=m/v
D= (82.49 g)/(90.32 cm^3)
D= 0.913 g/cm^3
I had a clear block. I think it’s Gamma.
V = l x w x h
V = (2.39 cm) (3.15 cm) (8.16 cm)
V = 61.4 cm^3
m = 70.64 g
D = m/V
D = 70.64 g / 61.4 cm^3
D = 1.15 g/cm^3
Guys who’s typing it? When is it due?
Didn’t we kind of volunteer you as tribute to type? lol. I’m pretty sure it’s due this Friday, that’s what we told Mrs. Skinner.
Didn’t we kind of volunteer you as tribute? lol. I’m pretty sure it’s due this Friday. That’s what we told Mrs. Skinner.
whoops didn’t mean to type twice
Milky white: Beta (0.967 g)
V=lwh
V= (4.01)(1.21)(8.02)
V=38.9 cm^3
D=m/V
D= 37.64 g/cm^3 / 38.9 cm^3
D= 0.967 g
And Tina, during class, you volunteered to type it up. Is that still ok with you or did you change your mind?
Yeah it’s fine. I wasn’t sure. Ok then…..
Is the lab supposed to be typed up like a normal lab or is it supposed to just be on the sheet?
gray: epsilon
mass: 77.88g
volume: (7.10cm)(1.20cm)(6.45cm)
volume: 54.95 cm^3
Density= m/V
Density= 77.88g/54.954 cm^3
D= 1.42 cm^3
color: paper white
mass: 42.22g
V= L x W x H
V = (8.60 cm)(8.09 cm)(1.30 cm)
V = 90.45 cm^3
D=m/V
D= (42.22 g) / (90.45 cm^3)
D= 0.47 g/cm^3
I believe the paper white block is “Alpha”
** 0.467 g/cm^3
I have measure my black block multiple times. I’ve also tried averaging the lengths, widths, and heights of each side of the block. (my corners on my block are bent) Plus I even measured a second black block and I cannot determine what the “name” is. The first time I found the volume, I used my tracing to measure in centimeters and I was closest to Delta, but why would I use my tracing as my final measurements. Here are at least 3 times when I measured and they varied because the mass the balance gave me was uncertain. The third set of calculations is used by an average of the masses the balance gave me, an average of the length ( I measured each side of the block), an average of the width ( I measured each side of the block), and an average of the height ( I measured each side of the block.) Also the fourth set is the 2nd black block I measured. Also Ms. Skinner told me to average today. What if we averaged the mass of the black blocks and then the average of the volume of the black blocks to get an average density that could be close enough to a block name? And then do it with all of the colors!
Black block- 2nd trial:
m= 78.88 g
V= lwh
V= (8.25 cm)( 7.62 cm)( 1.27 cm)
V= 79.8 cm^3
D= m/ V
D= 78.88 g/ 79.8 cm^3
D= 0.988 g/cm^3
0.988 g/cm^3 is closest to Beta
black block 3rd trial:
m=78.85 g
V= lwh
V= (8.25 cm)(7.53 cm)(1.28 cm)
V= 79.5 g/ cm^3
D= m/ V
D= 78.85 g/ 79.5 cm^3
D= 0.992 g/ cm^3
This density is closest to Beta.
Black block – 3rd trial (all measurements are averaged)
m= 78.86 g
V= lwh
V= (8.22 cm)( 7.68 cm)(1.23 cm)
V= 77.64 cm^3
D= m/V
D= 78.86 g/ 77.64 cm^3
D= 1.01 g/cm^3
This density is closest to Beta.
black block- completely different black block
m= 100.69 g
V= lwh
V= (7.62 cm) (5.13 cm) (2.53 cm)
V= 98.9 cm^3
D= m/V
D= 100.69 g/ 98.9 cm^3
D= 1.02 g/cm3
This density is closest to Beta.
I understand some people think that black is Delta, but based on all of my calculations I believe black is Beta. If we are turning this in tomorrow then I think we should collaborate together and come up with an answer. I’ve noticed several confusions with milky white and black and Beta and Delta. Please reply to this asap!!! 🙂
I had the white block and the density I got was 0.61g/cm^3. So it is close to Alpha.
m= 31.72 g
V=lwh
V= (14.18 cm)(3.28cm)(1.23cm)
V= 57.21 cm^3
D=m/V
D=31.72 g/ 57.21 cm^3
D= 0.61 g/cm^3
*paper white
I think averaging them together is a great idea, Micah!
So I redid my measurements for my paper white block:
m = 40.85 g
V = l x w x h
V = 93.1 mm x 68.9 mm x 13.0 mm
V = 83389.67 mm^3
QS = QG x CF
x cm^3 = 83389.67 mm^3 x 1 cm^3 / 1000 mm^3
x = 83.38967 cm^3
D = 40.85 g / 83.38967 cm^3
D = 0.4899 g/cm^3
so based on the comments:
everyone with paper white have said Alpha
everyone with grey have said Epsilon
everyone with clear have said Gamma
But milky white and black have both Beta and Delta so we need to pick which is which
Color: Clear
Block “Name”: Gamma
I believe that the clear block is Gamma. The density of my clear block is
1.10 g/cm^3, and the density of Gamma is 1.17 g/cm^3.
V= l x w x h
V= 7.20 cm x 9.70 cm x 1.30 cm
V= 90.792 cm^3
D= m/V
m= 99.69 g
V= 90.792 cm^3
D= 99.69 g/ 90.792 cm^3
D= 1.098 g/cm^3
D= 1.10 g/cm^3
***** I think that the clear block is Gamma because it is the closest to it. Density of block= 1.10 g/cm^3 and the Density of Gamma is 1.17 g/cm^3.
I’m 100% sure that the milky white is Beta… I got the EXACT same number for my answer as it was listed on the sheet
mass: 62.92 g
volume: (6.80cm)(3.65cm)(3.65)
volume: 90.59 cm^3
density: m/v
density: 67.92 g / 90.59 cm^3
D= 0.75 g/cm^3
mine is sort of off, but its closest to Alpha
I’m pretty sure my measurements were off or something, I don’t know how they could have been, but everyone with clear said Gamma so I would say it’s Gamma.
When is this due and who is writing it up? We need to help each other out, (especially helping the person who has to type it up). We need to make it easy and clear so that it is as stress-free as possible for them 🙂
Hey guys!!! I think we need to move our deadline back a few days and here is why:
I’ve talked to Mrs. Skinner and she pointed out some things. First off, most of us have only submitted one trial. As we’ve learned in class and lab, a scientist never does an experiment once- we should always do multiple!!! So most of us are going to need extra time to do more than one trial!! These blocks have been dropped and scratched and all kinds of stuff so the measurements may vary in each trial! And of course we need to average those trials. I think for two or three of the blocks we have a pretty unominous decision but we still need to prove our work. Just because it’s a weird format doesn’t mean it’s different than class 🙂
Also, the person “submitting” our answers doesn’t have to do a write up (this is what Mrs. Skinner told me). Tina: are you still okay with being our spokesperson?
I say we move our date to Tuesday or Wednesday of next week for our final measurements and trials so that way they are in before fall break, and Tina (or whoever) has plenty of time to submit our final answer and we have time to collaborate, especially on the black and milky white blocks. Please tell your thoughts/opinions and any suggestions you have!!
I’m down with doing it. So it’s just the sheet?
Sounds good, Olivia! Thanks so much for organizing everything! 🙂
OK so we have a problem…. I need to now who has milky white and black.
I had paper white
I had black. Also just like Olivia said, we all need to do our measurements atleast 3 times, then take each colored block’s mass and average them together and same with the volume to get an average density. We aren’t done yet. Just because someone’s measurements were quite precise to the measurement of the name doesn’t prove anything. As scientists we need to have several trials and collaborate. Because tomorrow is sort of a calm day, I think everyone should go back and find their block and redo the measurements atleast 2 more times. Then report ALL 3 of your trials and average them then we can average the colors separately.
Also, Tina this isn’t something you’re turning in I don’t think. I’m pretty sure we are all working together to find the name that matches the color and then you will post a final comment saying which color goes with which name. Guys just because Tina is the spokesperson does not mean that she has to go back and look at all of our comments and try and figure out which goes with which.
each time my grey was the same length but the mass changed. the first and second were 77.87, 77.88, and 78.1.
**first, second, and third
I had the milky white block… and I am going to go tomorrow morning and remeausure the block and I’ll re-comment my results 🙂
Are we turning this in tomorrow? I’m sorry this is probably a dumb question.
I sure hope not but I honestly am not sure
I have to send her an email by before tomorrow I think she said. What I’m going to do is take all the density of whaterver block and average it and base the name off that. Do you think that is ok?