Question

A chemist prepares a solution by adding 348 mg of K2Cr2O7 (MW = 294.19 g/mol) to a volumetric flask, and then adding water until the total volume of the contents of the flask reaches the calibration line that indicates 750 mL . Determine the molarity of the prepared solution. Express the concentration in moles per liter to three significant figures. ► View Available Hint(s) Templates Symbols undo redo 'reset keyboard shortcuts help concentration = mol/L Submit Previous Answers

Answer 1

. Molarity = moles of solute : Volume of solution (ind) Moles = mass.. molas-mass. 750 x 10-3 Moles of Ky Cry 0.7 = 348 x10-3 g = 1.183 x 10-3 . . 294:19 g/mol . Molority = moles of K₂ Cr 2 Oz - 1183 x 10-3 mod to Voli lind) = 1.577 X10-3 M Molarity = 1567 x 10-3 M I rounded off to 8 3 sigofig Hence, molarity of the prepared solution = 1.58×10 3 M) 7 :11.58x10-3 ^} 3 significant figuren ③. Molanity = moles of solute Volume of solution (ind) moles of Tila = diisi Mx. 100 x103 e . .. = 0.0151 moles is moles of cf ions = 3 x moles of Tica = 3 x ooisi moles = 0.0453 moles " Mass = moles & Imolas-mass) Mass of chloride ioms = 10.0453 mod) x (25.45 g/mol) = 60.58 g = 61, 3 significant figures rounded figure

Hence, mass of chloride = 1.61 g 1 t 3 signitiont figures ②. Molority = moles of Volume of solute solution (in es . moles of Hee = = 5.22 M X 389 . 10-3 l. 5.22 x389x10-3 moles o final volume of solution = 389 me . + 123 ml = 512 md SALE $12 x10-3 l .:, Molonity of new solution = moles of Hee . final volume 5-22 X 389 xloos M 512 x103 = 3.966 M = 3.97 M ... 3 significant figures wounded off Molority os concentration of solution = 3.97M 43 sinif