Formic acid, HCHO_2, is a convenient source of small quantities of carbon monoxi
ID: 971200 • Letter: F
Question
Formic acid, HCHO_2, is a convenient source of small quantities of carbon monoxide. When warmed with sulfuric acid, formic acid decomposes to give CO gas. HCHO_2(l) rightarrow H_2O(I) + CO (g) If 3.85 L of carbon monoxide was collected over water at 25 degree C and 689 mmHg, how many grams of formic acid were consumed? (The partial pressure of the water vapor at 25 degree C is 23.8 mmHg) How many milliliters of 0.250 M KMnO_4 are needed to react with 3.36 g of FeSO_4? 10FeSO_4(s) + 2KMnO_4(aq) + 8H_2SO_4(aq) rightarrow 5 Fe_2(SO_4)_3 + 2MnSO_4 + K_2SO_4 + 8H_2OExplanation / Answer
partial pressure of CO = (689 - 23.8)/760 = 0.875 atm
no of mol of CO = PV/RT = (0.875*3.85)/(298*0.0821) = 0.138 mol
No of mol of formicacid reacted = 0.138 mol
mass of formic acid consumed = 0.138*46 = 6.348 grams
8) No of mol of feso4 = 3.36/151.908 = 0.221 mol
No of mol of KMnO4 REACTED = 0.22*2/10 = 0.044 mol
volume of KMnO4 = 0.044 / 0.25 = 0.176 L = 176 ml