Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: MysteriousEd on October 27, 2013, 10:21:12 AM
-
I really don't understand these questions, I know it is not allowed to answer people's question, but I need help on how to answer these questions. I am failing chemistry lab, so I need to do good. That's why I am asking for help.
1) A medical laboratory scientist needs to prepare 500.0 mL of a solution that is 5.0 mM in K+ for diluting serum. What volume, in mL, of a 5.0% (m/v) KCI solution is required to make this solution?
2) How many mL of a 1.0% m/v stock solution are needed to prepare 50.0 mL of a 0.20% solution?
3) How many grams of Na2SO4 are contained per liter of a 0.500 M solution?
4) How many grams of MgCl2 are needed to prepare 750 mL of a 0.50 M solution?
5) A solution is prepared by dissolving 125g of Na3PO4 in enough water to make two liters of solution. Determine the concentration of this solution in units of : A) % m/v , B) molarity (i.e., mol/L) C. osmolarity (i.e., osm/L)
6) What is the molarity of a solution made by dissolving 25 g of NaCl in 750 mL of water?
7) How many grams of NaCl are needed to prepare 3.0 L of a 5.0 % m/v solution?
8) What is the concentration in % m/v of a solution prepared by dissolving 35 g of NaOH in enough water to make 2.5 L of solution?
9) A 15% m/v solution is prepared by diluting 50mL of a stock solution with water up to 125 mL of solution. What is the concentration of the stock solution in % m/v?
10. If a patient has a fasting blood sugar of 76 mg/dL, what is his blood sugar in mmol/L?
11: What is the osmolarity of a 2.2 M solution of MgCl2?
12: What is the molarity of a 0.25 Osm solution of NaCl?
13: What is the concentration in % m/v of a 2.0 M NaOH solution?
-
It appears you are asking us to do your quiz for you
According to forum rules that is a not allowed
please read forum rules
-
It appears you are asking us to do your quiz for you
According to forum rules that is a not allowed
please read forum rules
OK, sorry. It is just that I am failing, but you know, I prefer to fail if I don't understand rather than passing and not understanding.
How about we do some questions and you can give me the formula and I will solve it, hopefully? I will then practice using the formula provided until I get it. There will be questions like this on the exam, so I wanna make sure I get it.
-
For number 11 , I got 6.6. Is it correct?
For number 7 I got 150g.
-
OK, sorry. It is just that I am failing, but you know, I prefer to fail if I don't understand rather than passing and not understanding.
How about we do some questions and you can give me the formula and I will solve it, hopefully? I will then practice using the formula provided until I get it. There will be questions like this on the exam, so I wanna make sure I get it.
I am inclined to think that you were given the equations for these problems somewhere prior to the assigned homework. I would look over the equations, make sure all units are converted to the proper unit of measure and see which equation you can plug your units in to.
-
I know that already, but I don't know how to use those equations. I'll just try my best .. 40 points is a lot and I am sure I will get around 10 points out of 40! No life savers here :( I at least want someone to help me out with just a few problems, like 5-6 questions, short ones.