Molarity is defined as moles of solute, which in your case is sodium hydroxide, #"NaOH"#, divided by liters of solution.
Notice that the problem provides you with the volume of the solution, but that the volume is expressed in milliliters, #"mL"#. Moreover, you don't have the number of moles of sodium hydroxide, you just have the mass in grams. So, your strategy here will be to
So, to get the number of moles of solute, use sodium hydroxide's molar mass, which tells you what the mass of one mole of sodium hydroxide is.
The volume of the solution in liters will be
Therefore, the molarity of the solution will be
Rounded to one sig fig, the answer will be
In order to continue enjoying our site, we ask that you confirm your identity as a human. Thank you very much for your cooperation. Definitions Solute-the substance being dissolved Solvent-the substance doing the dissolving (the larger amount) Solution- a homogeneous mixture of the solute and the solvent Solution= solvent + solute Aqueous (aq)= water solution Tincture= alcohol solution Amalgam= Mercury solution Molarity (M)- is the molar concentration of a solution measured in moles of solute per liter of solution.  The molarity definition 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 sucrose are dissolved to make 2.0 liters of solution.
Level 2- Given Molarity and liters of solution Determine the number of moles of salt dissolved in 5.0 liters of a 0.50M solution of salt water.
cross multiply, X= 2.5 mols Level 3- Given grams (instead of moles) and liters of solution Determine the molarity when 117g of NaCl are dissolved to make 0.500 liters of solution. 1st convert to moles, 2nd plug into the molarity equation 117g NaCl( 1mol/58.5g)= 2.00mol NaCl
Level 4-Given grams (instead of moles) and milliliters of solution (instead of liters) Determine the molarity when 55.5g of CaCl2 are dissolved to make 250.mL of solution. 1st convert to moles, 2nd convert to liters, 3rd plug into the molarity equation 55.5g CaCl2( 1mol/111g)= 0.500mol CaCl2 250.ml( 1L/1000mL) =0.250L
Past Regents Questions-Follow link to check the answers Jan 2003-44 What is the molarity of a solution of NaOH if 2 liters of the solution contains 4 moles of NaOH?
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 contains 0.50 mole of NaOH in 0.50 liter of solution?
Aug. 2006-42 How many total moles of KNO3 must 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 total number of moles of NaCl(s) needed 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 defined 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 phrase describes 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) contains the greatest number of moles of solute particles? 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 defined 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 can be used 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 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 contains 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 on to ppm or Molality back to Math of Chemistry Links
500 ml of a solution contains 20 grams of NaOH (mw = 40). Calculate the molarity of the solution. 20 gr of NaOH correspond to 0.5 moles which are contained in 0.5 liter of solution. In one liter of solution there will be (2) (0.5) = 1 please and thus the solution is 1 M. What is the molarity of a solution containing 10g of NaOH in 500 mL of solution ?, 5 mol L − 1. Furthermore, How many grams of NaOH are there in 500 mL of a 0.225 M NaOH solution ?, Therefore, mass of NaOH in 500 mL of 0.225 M NaOH solution is 4.5 g. Finally, What is the molarity of a solution that contains 8.4 g of NaOH in 240.0 mL of solution ?, What is the molarity of a solution that contains 8.4 g of NaOH in 240.0 mL of solution. Show all work. All tutors are evaluated by Course Hero as an expert in their subject area. 8.4 g NaOH = mass / molar mass = 8.4 g / 40 g / mole = 0.21 mole. See also What is defined as brake fatigue? Frequently Asked Question:The molarity of NaOH is 2,002 x 10 –2 moles x 1000 mL/ L / 25.0 mL = 0.801 Molar. The molarity of the NaOH solution is found by dividing the moles of NaOH by the liters of NaOH solution required to reach the endpoint of the titration. Therefore 5g of NaOH is present in 250mL of 0.5M NaOH solution. Number of moles of NaOH = 20gm40gm / mol = 0.5 moles. Therefore, 20 gm NaOH dissolved in 500 ml of solution has 1M of molarity. 1 Answer. Under 4.0⋅g of sodium hydroxide. 4. 500 ml of a solution contains 20 grams of NaOH (mw = 40). The question asked: “What mass of solid NaOH is needed to make 500mL of 0.1M NaOH solution? ” To make one mole NaOH solutiondissolve 40 grams NaOH in 500mL of H2O. Explanation: It’s a 3.0 M solution so 1 liter of solution contains 3 moles of NaOH. 250 ml of solution therefore contains 0.25 x 3 = 0.75 moles of NaOH. The molar mass of NaOH is 39.9971 г./ mol, so 250 ml of this solution contains 0.75 x 39.9971 = 29.99 gor if you round it up 30.0 g. See also What is Mont Pantoja's real name? What is the molarity of a solution prepared by dissolving 10.0 grams of NaOH in enough water to make a solution with a total volume of 2.40 liters? 0.104 M NaOH. Number of moles of NaOH = 20gm40gm / mol = 0.5 moles. Therefore, 20 gm NaOH dissolved in 500 ml of solution has 1M of molarity. of moles of solute / volume of solution. ie 10/40 = 1/4 ie 0.25M. Requirements
Normality and molarity of sodium hydroxide are the same. The normality of 10% is 2.5 so, in theory at least, diluting it 25 times should render a normality of 0.1N. (Visited 112 times, 1 visits today) |
What is the molarity of a solution containing 20 grams of NaOH in 500?
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