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Given facts about a solution calculate its Molarity

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Given facts about a solution calculate its Molarity

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    1. Given facts about a solution calculate its Molarity What is a mole? What is Molarity? Avogadro’s number How to calculate molarity When is National Mole Day?

    2. The mole although a cute destructive creature… no! not that mole! What is a mole: “It is the quantity of a substance that has a mass in grams numerically equal to its formula mass; equal to 6.02X1023 molecules or atoms” quoted from Chemistry Connections to our changing world Or the mole can be defined as equivalent to the molecular weight of an atom or molecule in grams. Or the mole can be defined as equivalent to the molecular weight of an atom or molecule in grams.

    3. What is molarity? Molarity is a unit of concentration. It is the number of moles of a solute per liter of solution It s the more common used chemical unit of measurement.It s the more common used chemical unit of measurement.

    4. Avogadro’s number Number of atoms or molecules in a mole Avogadro’s number is an important topic and should be covered in another lesson plan.Avogadro’s number is an important topic and should be covered in another lesson plan.

    5. The Periodic Table MSDS sheets also contain the molecular weights of compounds. They also have other information. Always refer to a MSDS sheet when handling new chemicals. MSDS sheets also contain the molecular weights of compounds. They also have other information. Always refer to a MSDS sheet when handling new chemicals.

    7. Calculations The molarity of solution is calculated using the molecular weight of each compound, this is also known as the formula weight. The molarity of solution is calculated using the molecular weight of each compound, this is also known as the formula weight.

    8. Molarity of the sugar solution Question: A 4 g sugar cube (sucrose: C12H22O11) is dissolved in a 350 ml teacup filled with hot water. What is the molarity of the sugar solution? M = m/V where M is molarity (mol/L) m = number of moles of solute V = volume of solvent (Liters)

    9. Step 1 - Determine number of moles of sucrose in 4 g C12H22O11 = (12)(12) + (1)(22) + (16)(11) C12H22O11 = 144 + 22+ 176 C12H22O11 = 342 g/mol divide this amount into the size of the sample 4 g/(342 g/mol) = 0.0117 mol Molarity of the sugar solution continued

    10. http://chemistry.about.com/od/workedchemistryproblems/a/molarity.htm Step 2 - Determine the volume of solvent in liters 350 ml x (1L/1000 ml) = 0.350 L Step 3 - Determine the molarity of the solution M = m/V M = 0.0117 mol /0.350 L M = 0.033 mol/L Answer: The molarity of the sugar solution is 0.033 mol/L.

    12. Gram to Mole Conversions Problem Determine the number of moles of CO2 in 454 grams. Answer First, look up the atomic masses for carbon and oxygen from the Periodic Table. The atomic mass of C is 12.01 and the atomic mass of O is 16.00. The formula mass of CO2 is: 12.01 + 2(16.00) = 44.01 http://chemistry.about.com/od/workedchemistryproblems/a/molarity.htm

    13. Thus, one mole of CO2 weights 44.01 grams. This relation provides a conversion factor to go from grams to moles. Using the factor 1 mol/44.01 g: moles CO2 = 454 g x 1 mol/44.01 g = 10.3 moles Answer 10.3 moles CO2 http://chemistry.about.com/od/workedchemistryproblems/a/molarity.htm Gram to Mole Conversions

    14. Determine the molarity of a solution Example: What is the molarity of a solution made when water is added to 11 g CaCl2 to make 100 mL of solution? Answer: 11 g CaCl2 / (110 g CaCl2 / mol CaCl2) = 0.10 mol CaCl2 100 mL x 1 L / 1000 mL = 0.10 L molarity = 0.10 mol / 0.10 L molarity = 1.0 M http://chemistry.about.com/od/workedchemistryproblems/a/molarity.htm

    15. Prepare a M molarity solution Here's a quick overview of how to prepare a solution when the final concentration is expressed as M or molarity. You prepare a solution by dissolving a known mass of solute (often a solid) into a specific amount of a solvent. One of the most common ways to express the concentration of the solution is M or molarity, which is moles of solute per liter of solution. Example: Prepare 1 liter of 1.00 M NaCl solution. First calculate the molar mass of NaCl which is the mass of a mole of Na plus the mass of a mole of Cl or 22.99 + 35.45 = 58.44 g/mol Weigh out 58.44 g NaCl. Place the NaCl in a 1 liter volumetric flask. Add a small volume of distilled, deionized water to dissolve the salt. Fill the flask to the 1 L line. If a different molarity is required, then multiply that number times the molar mass of NaCl. For example, if you wanted a 0.5 M solution, you would use 0.5 x 58.44 g/mol of NaCl in 1 L of solution or 29.22 g of NaCl. http://chemistry.about.com/od/workedchemistryproblems/a/molarity.htm

    17. When is National Mole Day? National  Mole Day 6:02am to 6:02pm, October 23 6.02 x 1023 http://www.moleday.org/  Scientists and students around the  world celebrate Mole Day with various activities related to chemistry and/or moles.  Mole Day is celebrated annually on October 23 from 6:02 a.m. to 6:02 p.m. in honor of  Avogadro's Number (6.02 x 1023).

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