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Topic: help with aerobic repiration calculating volume displacement  (Read 3819 times)

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Offline THISMOMENTISFATE

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Respiration rate of plants vs animals experiment. not sure what to put in this table, or the calculations to d?
ok, i need to know the milliliters (mL) of NaOH to reach end point.
i have total volume of organisms (mL)
snails = 12 mL
elodea= 1 mL
elodea dark 1 mL
control 0 mL

we measures water displacement by measuring 75 ml of pond water in a 100 ml graduated cylinder. then we used 20 drops=1ml

please *delete me* ive been doing homework all day, just need to finish this one problem!

Offline Arkcon

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Re: help with aerobic repiration calculating volume displacement
« Reply #1 on: July 15, 2012, 08:34:51 PM »
Wow.  OK.  This is going to be a real tough one for us, because your question, as you post it, doesn't make sense.  I'm going to try to tell what's wrong, and I hope you can improve this question so we can help you more.

Respiration rate of plants vs animals experiment.

Seems like a reasonable experiment.

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not sure what to put in this table,


What table?

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or the calculations to d?

And d is ... what?

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ok, i need to know the milliliters (mL) of NaOH to reach end point.

OK, if this is to mean anything, you will need a balanced chemical equation, sooner or later.  Better sooner, to help us understand the experiment better, and then later we'll use it for calculations.  What end point?  What was there preventing it from reaching the end point, that needed mL of NaOH?  This sort of info can't be left out.

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i have total volume of organisms (mL)
snails = 12 mL
elodea= 1 mL
elodea dark 1 mL
control 0 mL

Alright, now this really needs an explanation.  Snails measured by mL is a real WTF? moment for me.

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we measures water displacement by measuring 75 ml of pond water in a 100 ml graduated cylinder. then we used 20 drops=1ml

Kay, we can work with this if we have to.  But how are you comparing end point and displacement.

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please *delete me* ive been doing homework all day, just need to finish this one problem!

What is the one problem?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline THISMOMENTISFATE

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Re: help with aerobic repiration calculating volume displacement
« Reply #2 on: July 15, 2012, 08:43:35 PM »
lol hold on let me post up the tasksheet that we did that would be more simple.

EDIT: i attached part of my task sheet. the highlighted part is what we got in class.

sorry about the confusion.

Offline fledarmus

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Re: help with aerobic repiration calculating volume displacement
« Reply #3 on: July 16, 2012, 11:27:29 AM »
The instructions seem pretty straightforward - in your first empty column, you put the number of mL of sodium hydroxide required to reach the endpoint (solution stays pink) - these are your experimental results. In the next empty column, the instructions say "To calculate the relative respiration rate of each organism, subtract mL NaOH added to the control beaker from the milliliters added to each beaker" - so from each value in column 2, subtract the value from the 4th row in column 2. In the third empty column, "To determine the respiration rate per milliliter of organism, divide the relative respiration rate by the volume of each organism" (divide each value in column three by the corresponding value in column 1)

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