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

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

Vocab. Lesson

Incorrect= The equipment is 5.0 Molarity.

Correct= The systems is 5.0 Molar.

Example Problems

Level 1- given moles and also liters

Determine the molarity as soon as 3.0 mole of sucrose are dissolved to make 2.0 liters that solution.

3.0 mol= X = 1.5M solution
2.0 liters

Level 2- provided Molarity and also liters the solution

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

X mol= 0.5M solution
5.0 liters

cross multiply, X= 2.5 mols

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

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

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first convert to moles, 2nd 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 milliliters of equipment (instead that liters)

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

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

55.5g CaCl2( 1mol/111g)= 0.500mol CaCl2

250.ml( 1L/1000mL) =0.250L

0.500 mol= 2.00M solution
0.250 liters

Past Regents Questions-Follow attach to examine the answers

Jan 2003-44 What is the molarity of a equipment of NaOH if 2 liters of the solution includes 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 systems containing 20 grams of 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 that a equipment that consists of 0.50 mole of 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 full moles that KNO3 need to be dissolved in water to make 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 variety of moles that NaCl(s)needed to do 3.0 liters of 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) moles of solute per liter the solution(3) mass of a solution(4) volume the a solvent

Aug 2008-15 i m sorry phrase describes the molarity of a solution?(1) liters that solute every mole that solution(2) liters of equipment per mole that solution(3) mole of solute per liter that solution(4) mole of solution per liter that solution

June 2009-46 i beg your pardon 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 together 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 total of(1) 3.0 grams the HCl every liter of water(2) 3.0 grams of HCl every mole of solution(3) 3.0 moles of HCl per liter of solution(4) 3.0 mole of HCl every mole that water

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

Jan 2008-15 i m sorry unit deserve to be provided to express systems 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 that 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 contains 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