molar concentration/molarity

Molar Concentration or molarity is the #of moles  of solute dissolved in a 1 L of solution.
- represented by M and it has the units of "mols/L."
The formula of Molarity = moles of solute (mol)
                                         volume of solution (L)
 M = mol/L.
 mol = M x L and L = mol/M are ways to find the mol and volume.


1) Calculate molar concentration that has a solution of 0.620 moles of CaCl2 in 1.7 L of solution.
2)Calculate the number of grams of sodium hydroxide in 3200mL of a 1.2 M KF solution.
3) Calculate the volume of L of 0.780 M NaCl solution that contains 55.21 g NaCl.


Answers:
1) M =0.620mol/ 1.7L 
=0.36(remember your sigfigs) 

2) 3200ml = 3.2 L
1.2M x 3.20L= 3.84 mols
convert mols to grams -------> 3.84 mols x 58.1g   = 223.104g--------------->220g
                                                                      1 mol
3) MM of NaCl = 58.5 g/mol
    55.21 g x 1 mol / 58.5 g
    = 0.944
L solution = 9.44444 moles of NaCl / 0.780
                = 12.108L




Post: JN 

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