Question
I need help working the problems, I don't know how I got the right answers
Calculate each of the following quantities:
(a) Grams of solute in 185.8 mL of 0.267 M calcium acetate
(b) Molarity of 500. mL of solution containing 21.1g of potassium iodine
(c) Moles of solute in 145.6 L of 0.850 M sodium cyanide
Calculate each of the following quantities:
(a) Grams of solute in 185.8 mL of 0.267 M calcium acetate
(b) Molarity of 500. mL of solution containing 21.1g of potassium iodine
(c) Moles of solute in 145.6 L of 0.850 M sodium cyanide
Answers
DrBob222
You just posted this question one or two posts below WITH answers and I told you all of the answers were ok.
Emily
I know I just posted that question, I got answer from someone but they didn't show me how to work the problem, so I wasn't asking if you could show me how.
DrBob222
(a) Grams of solute in 185.8 mL of 0.267 M calcium acetate
<b>Moles solute = M x L. Then moles x molar mass = grams.</b>
(b) Molarity of 500. mL of solution containing 21.1g of potassium iodine
<b>M = moles/L. 21.1/molar mass KI = mols KI and divide by 0.5L.</b>
(c) Moles of solute in 145.6 L of 0.850 M sodium cyanide
<b>moles = M x L </b>
<i>Note: To work any of this type problem just remember the definition of molarity. M = # moles/L solution. That's all you need. Between that and moles = g/molar mass you can work 99% of the solution problems. The molality ones are slightly different but only slightly. molality = # moles/kg solvent. That's three simple equation will get 99.9% of the solution problems you NORMALLY run into. They won't solve the mole fraction problems but most everything else they will. </i>
<b>Moles solute = M x L. Then moles x molar mass = grams.</b>
(b) Molarity of 500. mL of solution containing 21.1g of potassium iodine
<b>M = moles/L. 21.1/molar mass KI = mols KI and divide by 0.5L.</b>
(c) Moles of solute in 145.6 L of 0.850 M sodium cyanide
<b>moles = M x L </b>
<i>Note: To work any of this type problem just remember the definition of molarity. M = # moles/L solution. That's all you need. Between that and moles = g/molar mass you can work 99% of the solution problems. The molality ones are slightly different but only slightly. molality = # moles/kg solvent. That's three simple equation will get 99.9% of the solution problems you NORMALLY run into. They won't solve the mole fraction problems but most everything else they will. </i>
Emily
Thank you so much
berryl
This post really help me a lot. TQ!