Molarity (M)- is the molar concentration that a equipment measured in moles of solute every liter that solution.

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The molarity definition is based on the volume that the solution, not the volume the water.

Vocab. Lesson

Incorrect= The solution is 5.0 Molarity.

Correct= The systems is 5.0 Molar.

Example Problems

Level 1- provided moles and also liters

Determine the molarity once 3.0 mole of sucrose are dissolved to do 2.0 liters the solution.

3.0 mol= X = 1.5M solution
2.0 liters

Level 2- provided Molarity and liters of solution

Determine the number of moles that salt liquified in 5.0 liters the a 0.50M systems of salt water.

X mol= 0.5M solution
5.0 liters

cross multiply, X= 2.5 mols

Level 3- provided grams (instead of moles) and also liters of solution

Determine the molarity once 117g of NaCl are dissolved to make 0.500 liters the solution.

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1st convert to moles, second plug right 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 that moles) and also milliliters of solution (instead of liters)

Determine the molarity when 55.5g the CaCl2 are dissolved to make 250.mL that solution.

1st convert to moles, second convert come liters, third plug 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 examine the answers

Jan 2003-44 What is the molarity the a solution of NaOH if 2 liters of 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 the a equipment containing 20 grams that NaOH in 500 milliliters the solution?

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

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

Aug. 2006-42 just how many complete moles that KNO3 need to be liquified in water to do 1.5 liters that 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 variety of moles that NaCl(s)needed to do 3.0 liters that 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 characterized as the(1) mole of solute per kilogram of solvent(2) mole of solute per liter that solution(3) massive of a solution(4) volume the a solvent

Aug 2008-15 i beg your pardon phrase describes the molarity of a solution?(1) liters of solute per mole of solution(2) liters of equipment per mole the solution(3) mole of solute every liter the solution(4) mole of systems per liter of solution

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

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

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

Jan 2008-15 i m sorry unit can be supplied 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 equipment containing 20 grams the NaOH in 500 milliliters the solution?(1) 1 M (3) 0.04 M(2) 2 M (4) 0.5 M

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