# chemistry

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Convert .25 L of a .025 M solution of NaCL starting with solid NaCI and water

• chemistry -

Convert to what?

• chemistry -

the question actually reads "how would you MAKE .25L of a 0025M solution of NaCL starting with solid NaCL and water? 2nd Q: ends with starting with 2.0M NaCL?
Based on a lab that we haven't even had yet.....lost.
txs

• chemistry -

How many moles NaCl do you want? That is M x L = 0.25L x 0.0025M = 0.000625 mol.
Then mol NaCl = grams NaCl/molar mass NaCl
g = mol x molar mass = about 0.0006 x 58 or so = about 0.036g NaCl.

For the second one.
mL1 x M 1 = mL2 x M2
which is the dilution formula. You may have seen it as c1v1 = c2v2.

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Luckily I can ask for more help tomorrow...lol
Is the formula different for "how would you make 40mL of 30%ETOH starting with 75% ETOH and water" different (because it's all liquid vs. solid and liquid?) txs

• chemistry -

How many grams each of cacodylic acid and sodium cacodylate trihydrate, do you need to add to 2.00 L of water to prepare a pH 5.60 buffer solution with a total buffer
concentration ([(CH3)2AsO2H] + [(CH3)2AsO2
-]) equal to 0.0100 M?

• chemistry -

Sometimes we can make sense of questions when they lack completeness because we know the background but ONLY when screen names don't change. I don't understand the last two and I don't know if I am dealing with the same poster or not. Please repost as a new question at the top of the page; also, it helps if you don't change screen names.