Mastering Chemistry: Hwa28-Elemental Analysis Google Chrome https:// Schafer Fal

Question

Mastering Chemistry: Hwa28-Elemental Analysis Google Chrome https:// Schafer Fall 2016 Chem 151 HWH28-Elemental Analysis Problem 6.12 Problem 6.121 sodium borohydride. NaBH a substance used in the synthesis of many pharmaceutical agents, can be prepared by reaction of NaH with B2H6 according to the equation: 2NaH B2H6 2NaBH. Ask me anything Part A How many grams of NaBH can be prepared by reaction between 8.60 g of NaH and 6.85 g of B2H6? My Answers Give Un Submit Part B Which reactant is limiting? NaH Submit My Answers Give Up Correct Part C How many grams of the excess reactant will be left over? m 3.0053 Submit My Answers Give up Incorrect, Try Again 4 attempts remaining A signed in as Miriam Adam I Hep close Resources previous l 8 of 8 I return to assignment Provide Feedback Continue 0:36 AM 11/15/2016

Explanation / Answer

A)
moles of NaH = mass of NaH / molar mass of NaH
= 8.60/24
= 0.36 mol

moles of B2H6 = mass of B2H6 / molar mass of B2H6
= 6.85/27.67
= 0.25 mol

Since NaH is limiting, we will use NaH
2 mol of NaH forms 2 moles of NaBH4

moles of NaBH4 formed = 0.36 mol
molar mass of NaBH4 = 37.83 g/mol
mass of NaBH4 = molar mass * number of mol
= 37.83 * 0.36
= 13.6 g
Answer: 13.6 g

C)
mol of B2H6 reacted = 0.36/2 = 0.18 mol
excess mol of B2H6 = 0.25 - 0.18 = 0.07 mol

mass of excess B2H6 = mol * molar mass
= 0.07 * 27.67
= 1.9 g
Answer: 1.9 g

Related Questions

Navigate

• Browse (All)
• Browse M
• Subjects

---