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

You are watching: Which solution has a molality of 0.25m nacl

The molarity meaning is based on the volume of the solution, NOT the volume of water.

Vocab. Lesson

Incorrect= The solution is 5.0 Molarity.

Correct= The solution is 5.0 Molar.

Example Problems

Level 1- Given moles and liters

Determine the molarity when 3.0 moles of succlimbed are dissolved to make 2.0 liters of solution.

3.0 mol | = X = 1.5M solution |

2.0 liters |

Level 2- Given Molarity and also liters of solution

Determine the number of moles of salt dissolved 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 (rather of moles) and liters of solution

Determine the molarity when 117g of NaCl are liquified to make 0.500 liters of solution.

See more: What Can I Hunt With A 22 - What Can You Hunt With A 22Lr

first 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 (rather of moles) and milliliters of solution (rather of liters)

Determine the molarity once 55.5g of CaCl2 are liquified to make 250.mL of solution.

1st convert to moles, second transform to liters, third plug right 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 inspect the answers

Jan 2003-44 What is the molarity of a solution of NaOH if 2 liters of the solution includes 4 moles of NaOH?

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

Jan. 04-41 What is the molarity of a solution 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 of a solution that consists of 0.50 mole of NaOH in 0.50 liter of solution?(1) 1.0 M (3) 0.25 M(2) 2.0 M (4) 0.50 M

Aug. 2006-42 How many full moles of KNO3 should be dissolved in water to make 1.5 liters of 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 complete number of moles of NaCl(s)essential to make 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) moles of solute per kilogram of solvent(2) moles of solute per liter of solution(3) mass of a solution(4) volume of a solvent

Aug 2008-15 Which expression defines the molarity of a solution?(1) liters of solute per mole of solution(2) liters of solution per mole of solution(3) moles of solute per liter of solution(4) moles of solution per liter of solution

June 2009-46 Which sample of HCl(aq)consists of the best number of moles of solute particles?(1) 1.0 L 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 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 of HCl per liter of water(2) 3.0 grams of HCl per mole of solution(3) 3.0 moles of HCl per liter of solution(4) 3.0 moles 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 of water(2) grams of NaCl per liter of solution(3) moles of NaCl per liter of water(4) moles of NaCl per liter of solution

Jan 2008-15 Which unit have the right to be provided to expush solution concentration?(1) J/mol (3) mol/L(2) L/mol (4) mol/s

Jan 04-41 What is the Molarity of a solution 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 of 1.5 liters of an aqueous solution that consists of 52 grams of lithium fluoride, LiF, (gram-formula mass =26 grams/mole)?(1) 1.3 M (3) 3.0 M(2) 2.0 M (4) 0.75 M