Question

Each week before you have chemistry lab, someone needs to prepare all the solutions you will use in your experiment. Suppose your experiment for next week calls for 0.500 M NaOH solution, 3.00 M NH4Cl solution, and 0.100 M Na3PO4 solution. Calculate the mass in grams for each solute that would be needed to prepare 8.00 L of each of the solutions. Calculate the mass, in grams, of solute present in each of the following solutions: a. 225 g of 2.91% ammonium nitrate solution b. 225 mg of 2.91% ammonium nitrate solution c. 100.0 g of 4.95% potassium bromide solution d 1.00 kg of 4.95% potassium bromide solution For each of the following solutions, the mass of solute is given, followed by the total volume of the solution prepared. Calculate the molarity. a. 1.37 g of NaOH; 125 ml b. 4.29 g Kl; 250,0 ml c. 2.95 mg of Pb(NO3)2; 4.95 ml 2007 be of NaNO: 125 L

Answer 1

a Molar reass of mach 40.0 g/mol 0.500M of 8.00L Neolt have to prepare No. of moles of Naalta 0.5 mde/ x 8.00 x = 40mole. - Mass of nach needed a 40.09 x 4 mole = 160g. Molar Mass of Nitael = 53.49 g/mol.1 3.00M A 8.0L of Nitael.) .. NO. A reoles of Nita el 23.00 x 8.0. = 24.00 mole . Mass of Nitael needed - 53.49 x 24.0 = 1283.76 g. 0.loom Naz poy of sino L No. A moles = 0.100 x 8.00 = 0.8 mole Molar Mass of Nag Pou = 163.94 g/mol Mass of Nas poy needed = 163.94 X 0.8 = 131.15g

# Considering, for 2,91% NHA Ng solution. In 2.919 NHANO dissolved in 100 ml water to make 2.91% solution i density of water 0.997 g/ml Mass of 100m2 2,41%. Alta No solution = 0.9978100 + 2.9) gi - 102.619 . 102.61 g solution Contains 2.91g Nitq Nos. - 225g soll contains : 2.91 x 225. 102.61 6.3809g 15 225 mg sol Contains 2.91 0.2251 102.61 20.00649 (C) 100ml of 4.95 g KBr sole = 100x0.997 +4,95 . = 104.65g. 104.65g Sole Contains 4.95.9 KBr. ... loog som - 4:951100 104.65 Ad) looog Sock = 4.738 4.95X1000 104.65 = 47.3 g

Molar Mass of maat = 40.0 g/mol Mass of macht = 1.37 g. . Moles of Nacht 1.37 -0.03425 mole - 40.0 Total volume 125 ml = 0,1252 Molarity 1 0.03425 mole) = 0.274M 0.125 (B) Molar Mass of KP 166.0 g/mol Mass of kI 2 4:29 g - Moles of K 2 2 4.29 = 0.0258 moles. - Goren - 166.0 volume = 250 ml. 0.250 L. Meolarity 0.0258 = 0.10344 co Molar Mass of Pb (NO) - 331.2 g/mol mass of Pb(NO 2.95 mg = 2.95816 Moles at Pb(NO) 2 2958103 - 331.2 = 8.907x10 more volume = 4.95 m2 =4.958103 . Molarity Milanite 8.9078106 2.95 x 0-3 = 1.799 410 M... we