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 review on density problems today, and more! Remember, in chemistry we use math as a tool, therefore we might work problems a little differently in chemistry than you do in your math class.
When working these problems, don’t forget to follow the problem solving steps we discussed today:
- Analyze – write down what you’re given and what you’re looking for
- Plan – write a formula where you isolate the unknown on one side by itself
- Compute – plug in your data, numbers and units; then cancel the units, and if they cancel correctly, go on to the calculator. Be sure and give your answer what the correct units.
- Evaluate – does your answer make sense, have you used the correct units, do you have the correct sig figs?
Need more practice? Help session TOMORROW morning, 7:30ish A.M.
I rate myself a 3 out of 5 this week because I feel like I have been engaged in class lectures but I do not need to forget my homework, and I am very excited to be able to do the lab.
I rate myself a 3 out of 5 because I have been learning alot but I need to get more on top of things and study hard for my next test.
George you are an idiot
More than one person can measure each block and we can compare answers to make sure everyone has consistent answers
Joy where did y’all get that ruler
mal which two have you done
Where r rulers
where do we find the rulers?
I got clear block mass as 59.384 g can someone check that
mal the blocks aren’t the same
I got black block mass as 78.859 g someone please compare answers
Madison did you get white to be alpha
I got the milky white block’s mass to be 61.82 g. Can someone please check it?
The blocks should be the same or we shouldn’t be able to share answers as a croup
The masses and volumes aren’t the same for two blocks of the same color but the densities are
Mary my milky white block mass was 59.38 g
post answers once you get them
Alright for the black block I got the density to be 0.9654g/cm^3. That is beta right? Any disagreements?
No
the destiny will be the same but the mass and volume won’t be, correct?
Yes Madison. The ratio should be the same
Blocks have destiny?
Very punny haha
***density 🙂
I got the black block density to be 0.996 but it’s just the error between people I think
The milky white block I have has 0.970 as its density
I got clear block density as 1.18 which matches Gamma
Actually I remeasured and got 0.940 for density
So is alpha paper white
I got 0.948 g/cm^3 for the milky white but it’s not one of the choices? meredith also got a similar answer
I think Gamma is the clear box. I got density to be 1.19 g/cm^3
This week, I rate myself a 4/5. At the beginning of the week, I struggled with the lab. Going through the week, I started to get a lot of the homework correct. I also understood a lot of chapter 2.
Gamma = Clear
-Caroline
Are you sure about any of the other ones Mal ?
-Caroline
I also got the density of the clear block to be 1.18 so i think that the clear block is Gamma
ALSO MS SKINNER SAID THAT WE GET TO DECIDE THE DUE DATE FOR THIS LAB SO WHENEVER PEOPLE CAN WORK DURING STUDY HALLS, DO IT UNTIL WE GET CONSISTENT RESULTS!!!
WOOHOO -C
what other blocks have you gotten ??? -C
also guys ms skinner said to not take sig figs in our volume calculations because we need to be as exact as possible until we get our final answer (density)
okay
okay so i just did density calculations on 2 milky white blocks and got 0.910 EXACTLY on BOTH of the blocks so i think Delta should be the milky white blocks
okay i found the density of the gray blocks twice and i got 1.43 and 1.42 so i think Epsilon is Gray
what color have we not done – Caroline
ive been doing blocks twice like with two different blocks of the same color to make sure it consistent and ive done milky white, gray, and im about to do black
I measured the density for paper white and got exactly 0.541
So I (Caroline) got
Alpha — Paper White
Beta — Black
Delta — Milky White
Gamma — Clear
Epsilon — Gray
-Caroline
And Mal is gonna be the spokes person -Caroline
I’m gonna go in tomorrow and check those numbers and post what I get
hey yall so i did calculations for two black blocks and i got about 0.979 g/cm^3 as the density and i know that one isn’t actually exact like the others, but it is closest to Beta (Caroline and Meredith also got Beta for Black). I’m going to come back in 7th period study hall tomorrow and finish working on Paper White, Clear, and a retry of Black so that I have accurate numbers to do calculations, but whenever anyone can come in to try to find the density of the blocks, please do that. And PLEASE post your results on here so that I can compare answers as much as possible to make sure my final answers are accurate!! I think we should make the due date for this lab some time next week, maybe Tuesday or Wednesday to give us all time to work on it.
I calculated the density of black block to be 1.47g/cm^3.
I also got paper white as alpha
Milky White Block Density:
MW mass = 61.467 g
MW l = 5.20 cm
MW w = 10.39 cm
MW h = 1.25 cm
MW V = l x w x h
V = 5.20 cm x 10.39 cm x 1.25 cm
V = 67.535 cm^3
MW D = m/V
D = 61.467 g / 67.535 cm^3
D = 0.910 g/cm^3
Gray Block Density:
G mass = 77.869 g
G l = 7.10 cm
G w = 6.45 cm
G h = 1.20 cm
G V = l x w x h
V = 7.10 cm x 6.45 cm x 1.20 cm
V = 54.954 cm^3
G D = m/V
D = 77.869 g / 54.954 cm^3
D = 1.42 g/cm^3
Do we each have to do all of the blocks?
Paper White Block Density:
l = 3.50 cm
w = 11.30 cm
h = 1.89 cm
V = l x w x h
V = (3.50 cm)(11.30 cm)(1.89 cm)
V = 74.7495 cm^3
m = 40.872 g
D = m / V
D = 40.872 g / 74.7495 cm^3
D = 0.547 g / cm^3
Clear Block Density:
l = 3.90 cm
w = 1.22 cm
h = 10.49 cm
V = l x w x h
V = (3.90 cm)(1.22 cm)(10.49 cm)
V = 49.91142 cm^3
m = 59.421 g
D = m / V
D = 59.421 g / 49.91142 cm^3
D = 1.19 g / cm^3
Milky White Block Density:
l = 7.20 cm
w = 1.25 cm
h = 4.50 cm
V = l x w x h
V = (7.20 cm)(1.25 cm)(4.50 cm)
V = 40.5 cm^3
m = 36.551 g
D = m / V
D = 36.551 g / 40.5 cm^3
D = 0.902 g / cm^3