Question

A student prepares a weak acid solution by dissolving 0.2000 g HZ to give 100. mL solution. The titration requires 33.5 mL of 0.1025 M NaOH. Calculate the molar mass of the acid. WebAssign will check your answer for the correct number of significant figures. g/mol (a) Would the molar mass be too high, too low, or unaffected if the student accidentally used 0.1000 g in the calculation

Answer 1

Answer:

a)M=0.20/(0.335*0.1025)= 0.20/ 0.034 = 5.88 g/mol

b) if 0.100g is used instead of 0.200g

M = 0.1 / 0.034 = 2.94  hence the molar mass will be too low

Explanation:

0.2000 gHZ gives  100ml acid solution

33.5 ml of 0.1025 M NaOH  is required to prepare it

the moles = mass / molar mass

mass = 0.200 gHZ

moles = 0.0335*100 * 0.1025 = 0.034

therefore molar mass = mass / moles

                                  M=0.20/(0.335*0.1025)= 0.20/ 0.034 = 5.88

if 0.100g is used instead of 0.200g

M = 0.1 / 0.034 = 2.94  hence the molar mass will be too low