w Blockboard https eringchemistrycommyctmasteringassignment

\\ w Blockboard https:/ eringchemistry.com/myct/mastering#/assignment/62897 12 MasteringChemistrys Chapter 4 Part 1 McMurry, Fay, and Robinson 7e-Google Chrome Secure https//session.masteringchemistry.com/myct/itemview assignmentProblemiD-99479293 Chapter 4 Part 1 McMurry, Fay, and Robinson Te Problem 4.49 with feedback PartA Constants I Periosdic Table 270.0 mL of 0.600 Methyl alcohol (C2HsO) Express the mass in grams to three significant digits. How many orams of solute would you use to prepare each of the following solutions? You may want to reference (Pages 114-116) Section 4 2 while completing this problem Submit Part B 169 mL of 0.180 M boric acid (H BO2) Express the mass in grams to three significant digits Submit to search

Solution

Ans :

Part A :

Molarity = no. of mol of solute / volume of solution in L

0.600 = n / 0.270

n = 0.162 mol

molar mass of ethyl alcohol = 46.07 g/mol

So the mass = 0.162 x 46.07

= 7.46 grams

Part B :

M = n / V

0.180 = n / 0.169

n = 0.03042 mol

Molar mass of boric acid = 61.83 g/mol

So the mass = 0.03042 x 61.83

= 1.88 grams