Homework Help: Chem

Posted by Jason on Sunday, November 7, 2010 at 10:48am.

Plese tell me if these are right.
A 15.0-mL sample of NaCl solution has a mass of 15.78g. After the NaCl is evaporated to dryness, the dry salt residue has a mass of 3.26g. Calculate the following concentrations for the NaCl solution.

a. %(m/m)= 3.26 x 100 / 15.78 = 20.7

b. %(m/v) = 3.26 x 100 / 15.0 = 21.7

c. molarity (m) Moles NaCl = 3.26 g / 58.4428 g/mol = 0.0558
M = 0.0558 mol / 0.0150 L = 3.72

How many grams of KI are in 25.0 mL of a 3.0%(m/v) KI solution. 3.0 = mass KI x 100 / 25.0
mass KI = 0.750 g

How many milliliters of a 2.5 M MgCl2 solution contain 17.5g Mg Cl2. Moles MgCl2 = 17.5 g / 95.211 g/mol= 0.184
V = 0.184 mol / 2.5 M = 0.0736 L => 73.9 mL

Chem - bobpursley, Sunday, November 7, 2010 at 11:05am
All correct.
Chem - Kariann, Tuesday, March 29, 2011 at 8:50pm
Can you show me step by step how you did the last two problem questions?
Chem - Anonymous, Tuesday, November 6, 2012 at 12:48am
will 400 g of sucrose dissolve in a teapot that contains 200 g of water at 70 celcious? explain

Answer this Question

Related Questions

chemistry - A 15.0ml sample of NaCL solution has a mass of 15.78g.after the NaCL...
chemistry - In a laboratory experiment, a 18.0 ml sample of NaCl solution is ...
ap chem - I'm supposed to find the mass of NaCl in 1 L & the mass of H20...
Chemistry - A 15.0% (by mass) NaCl solution is available.. Determine what mass ...
Chemistry - What is the molarity of a solution of Mg(OH)2 if the solution ...
chemisrty - Q4) Suppose you prepare 950 mL of a solution by dissolving 100 grams...
bio - You have a sample of NaCl that contains 100 mg/ml NaCl. You are trying to ...
Chemistry - 25.0 mL of a NaCl solution (concentration unknown) was found to ...
science - Q4.you will be asked to prepare 25.0 mL of a 0.019 M solution of ...
Chemistry - In a lab we are doing, we need to find the theoreical amount of NaCl...

For Further Reading

First Name:
School Subject:
Answer: