Question about How Salty Does the Sea Have to Be for an Egg to Float? activity

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Teresaecalia
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Question about How Salty Does the Sea Have to Be for an Egg to Float? activity

Post by Teresaecalia »

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How do you calculate the absolute and relative concentrations in this experiment?
How do we figure the densities of the eggs?

I have reviewed the info in science buddies but still don’t understand how to calculate those results. Will you please help me?

Thanks!

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Last edited by MadelineB on Sun Jan 09, 2022 5:10 pm, edited 1 time in total.
audreyln
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Re: Question about How Salty Does the Sea Have to Be for an Egg to Float? activity

Post by audreyln »

Hello,

This sounds like a fun experiment!

To calculate the absolute mass concentrations of cups 1-4 you'll need to start by calculating the mass concentration of your stock. The mass concentration is defined as the mass of a compound (in grams) in a certain solvent volume (in liters) and has the unit grams per liter (g/L). For example, in a solution with 750 grams of salt (sodium chloride or NaCl) in 1.5 liters of water, the mass concentration of salt is 750 g/1.5 L = 500 g/L. For this experiment you've used 1 cup of salt and 5 cups of water. You'll need to convert these to metric units and then divide the grams of salt by the liters of water. For reference, 1 cup of salt is 292 grams [g], 1 cup of water is 237 milliliters [mL] and 1 liter [L] is 1000 milliliters [mL].

Once you have the absolute mass concentration of your stock (cup 1) you can calculate the absolute mass concentrations of cup 2 using Equation 2 in the Introduction section. You'll then need to repeat this for cups 3 and 4 except for cup 3 the stock used was from cup 2 so you'll use that concentration in Equation 2 instead of the original stock concentration in cup 1.

Now that you have the absolute mass concentrations for cups 1-4 you can calculate the relative salt concentrations as explained in step 4h of the Experimental Procedure.

To determine the density of your eggs you'll look at your notes of which solution each egg floated in or sank in. If the density of the saltwater is less than the egg's density, the egg will sink, and if the density of the saltwater is greater than the egg's density, the egg will float. So the density of the egg would be between these two absolute salt densities.

Good luck!

Audrey
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