1. Molarity Problems Molarity = mol/L Molarity = moles of solute / Liters of solution

2. Concentration ~How much solute is present in a solution compared to the solvent. ~How much solute is present in a solution compared to the solvent. Molarity (M)- moles of solute per liter of solution. M = mol/L Molarity (M)- moles of solute per liter of solution. M = mol/L 2.1 M AgNO 3 means 2.1 mol of AgNO 3 for every one liter of solution 2.1 M AgNO 3 means 2.1 mol of AgNO 3 for every one liter of solution

3. Other measures of concentration Name Abbrev. What it is molalitymmol solute/kg solvent parts per millionppmg solute/g solvent x 10 6 parts per billionppbg solute/g solvent x 10 9 mole fractionxmol solute/mol solution percent by mass%g solute/g solution x 100 percent by volume%mL solute/mL solvent x100

4. Molarity problems How many moles of HCl are in 125 mL of 2.5 M HCl? How many moles of HCl are in 125 mL of 2.5 M HCl? 2.5 mol HCl 1 L of soln..125 L of soln =.31 mol HCl

5. Here we go What concentration solution would be prepared if 39 g of Ba(OH) 2 were mixed in a 450 mL solution? What concentration solution would be prepared if 39 g of Ba(OH) 2 were mixed in a 450 mL solution? 39 g Ba(OH) 2 1 mol Ba(OH) 2 171.316 g Ba(OH) 2 =.2276 mol Ba(OH) 2.2276 mol Ba(OH) 2.45 L of solution M = mol/L =.51 M Ba(OH) 2

6. More For a lab in this chapter, I need to make.60 L of 3.0 M NaOH, what mass of NaOH did I need? For a lab in this chapter, I need to make.60 L of 3.0 M NaOH, what mass of NaOH did I need?.6 L x 3.0 M NaOH = 1.8 mol NaOH.6 L x 3.0 M NaOH = 1.8 mol NaOH 1.8 mol NaOH x 39.998 g/mol 1.8 mol NaOH x 39.998 g/mol = 72 g NaOH = 72 g NaOH

7. Molarity Problems A0.24 Msolution of Na 2 SO 4 Na 2 SO 4 contains 0.36 moles of Na 2 SO 4. Na 2 SO 4. How many liters were required to make this solution? 0.36 mol Na 2 SO 4 1 L soln 0.24 mol = 1.5 L Na 2 SO 4

8. Getting tougher AgNO 3 + BaCl 2  AgCl + Ba(NO 3 ) 2 AgNO 3 + BaCl 2  AgCl + Ba(NO 3 ) 2 Balance the equation. If 1.2 L of.50 M AgNO 3 is reacted completely, what molarity solution of Ba(NO 3 ) 2 will be created if the volume increased to 1.5 L? Balance the equation. If 1.2 L of.50 M AgNO 3 is reacted completely, what molarity solution of Ba(NO 3 ) 2 will be created if the volume increased to 1.5 L? 22 AgNO 3 =.6 mol AgNO 3 1.2 L x.5 M AgNO 3 =.6 mol AgNO 3. 6 mol AgNO 3 1 mol Ba(NO 3 ) 2 2 mol Ag NO 3 NO 3 ) 2 =.3 mol Ba( NO 3 ) 2 1.5 L NO 3 ) 2 =.20 M Ba( NO 3 ) 2

9. Homework Problem HNO 3 + Zn  H 2 + Zn(NO 3 ) 2 HNO 3 + Zn  H 2 + Zn(NO 3 ) 2 If you have.45 L of 2.1 M HNO 3 and you react it completely what volume of H 2 gas will you produce at STP? If you have.45 L of 2.1 M HNO 3 and you react it completely what volume of H 2 gas will you produce at STP? Solve for moles of H 2, then use Avogadro’s law to get a volume at STP. Solve for moles of H 2, then use Avogadro’s law to get a volume at STP.