Molarity (M)- is the molar concentration of a systems measured in moles of solute per liter of solution.

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The molarity meaning is based upon the volume the the solution, no the volume of water.

Vocab. Lesson

Incorrect= The solution is 5.0 Molarity.

Correct= The equipment is 5.0 Molar.

Example Problems

Level 1- given moles and also liters

Determine the molarity once 3.0 moles of sucrose are dissolved to make 2.0 liters the solution.

3.0 mol= X = 1.5M solution
2.0 liters

Level 2- given Molarity and liters of solution

Determine the variety of moles the salt liquified in 5.0 liters of a 0.50M solution of salt water.

X mol= 0.5M solution
5.0 liters

cross multiply, X= 2.5 mols

Level 3- given grams (instead the moles) and liters of solution

Determine the molarity when 117g that NaCl are liquified to do 0.500 liters the solution.

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first convert come moles, second plug into the molarity equation

117g NaCl( 1mol/58.5g)= 2.00mol NaCl

2.00 mol= 4.00M solution
0.500 liters

Level 4-Given grams (instead the moles) and also milliliters of solution (instead the liters)

Determine the molarity as soon as 55.5g of CaCl2 are dissolved to do 250.mL the solution.

1st transform to moles, 2nd convert to liters, third plug right into the molarity equation

55.5g CaCl2( 1mol/111g)= 0.500mol CaCl2 1L/1000mL) =0.250L

0.500 mol= 2.00M solution
0.250 liters

Past Regents Questions-Follow link to check the answers

Jan 2003-44 What is the molarity the a solution of NaOH if 2 liters that the solution consists of 4 mole of NaOH?

(1) 0.5 M (3) 8 M(2) 2 M (4) 80 M

Jan. 04-41 What is the molarity that a equipment containing 20 grams that NaOH in 500 milliliters of solution?

(1) 1 M (2) 2 M (3) 0.04 M (4) 0.5 M

Jan 2002-42 What is the molarity of a equipment that has 0.50 mole the NaOH in 0.50 liter that solution?(1) 1.0 M (3) 0.25 M(2) 2.0 M (4) 0.50 M

Aug. 2006-42 exactly how many complete moles that KNO3 must be liquified in water to do 1.5 liters the a 2.0 M solution?

(1) 0.50 mol (2) 2.0 mol (3) 3.0 mol (4) 1.3 mol

Aug 2005-41 What is the total number of moles that NaCl(s)needed to do 3.0 liters the a 2.0 M NaCl solution?(1) 1.0 mol (3) 6.0 mol(2) 0.70 mol (4) 8.0 mol

June 2006-16 Molarity is identified as the(1) mole of solute every kilogram that solvent(2) mole of solute per liter that solution(3) fixed of a solution(4) volume the a solvent

Aug 2008-15 which phrase defines the molarity of a solution?(1) liters of solute every mole the solution(2) liters of solution per mole that solution(3) mole of solute per liter that solution(4) mole of systems per liter of solution

June 2009-46 i m sorry sample that HCl(aq)contains the greatest number of moles that solute particles?(1) 1.0 together of 2.0 M HCl(aq)(2) 2.0 l of 2.0 M HCl(aq)(3) 3.0 l of 0.50 M HCl(aq)(4) 4.0 together of 0.50 M HCl(aq)

June 2007-13 A 3.0 M HCl(aq)solution includes a total of(1) 3.0 grams the HCl every liter of water(2) 3.0 grams that HCl per mole that solution(3) 3.0 mole of HCl every liter of solution(4) 3.0 mole of HCl per mole of water

June 2010-14 The molarity of an aqueous solution of NaCl is identified as the(1) grams of NaCl per liter that water(2) grams of NaCl per liter the solution(3) mole of NaCl per liter of water(4) moles of NaCl every liter that solution

Jan 2008-15 i m sorry unit can be provided to express solution concentration?(1) J/mol (3) mol/L(2) L/mol (4) mol/s

Jan 04-41 What is the Molarity of a systems containing 20 grams of NaOH in 500 milliliters of solution?(1) 1 M (3) 0.04 M(2) 2 M (4) 0.5 M

Jan 2010-40 What is the molarity that 1.5 liters of one aqueous solution that has 52 grams the lithium fluoride, LiF, (gram-formula massive =26 grams/mole)?(1) 1.3 M (3) 3.0 M(2) 2.0 M (4) 0.75 M