Methanol (CH_3OH) is converted to bromomethane (CH_3Br) as follows: CH_3OH + HBr
ID: 511776 • Letter: M
Question
Methanol (CH_3OH) is converted to bromomethane (CH_3Br) as follows: CH_3OH + HBr rightarrow CH_3Br + H_2O If 12.23 g of bromomethane are produced when 500 g of methanol is reacted with excess HBr, what is the percentage yield? A) 59.1% B) 82.6% C) 12.9% D) 40.9% E) 33.8% What is the theoretical yield of vanadium that can be produced by the reaction of 40.0 g of V_2O_5 with 40.0 g of calcium based on the following chemical equation? A) 20.3 g. B) 11.2 g C) 5.6 g. D) 22.4 g E) 40.0 g Which substance is present in the smallest proportion in a solution? A) solid B) gas C) solvent D) liquid E) solute Which process defines how molecular compounds form ions upon dissolution? A) decomposition B) ionization C) composition D) dissolution E) division) Which of these compounds is a weak electrolyte? A) C_6H_12O_6 (glucose) B) HCI C) N_2 D) KCI E) NH_3 Which chemical equation describes an acid-base neutralization reaction? A) 2Al(s) + 3H_2SO_4(aq) rightarrow Al_2(SO_4)_3(aq) + 3H_2(g) B) 2SO_2(g) + 2H_2O(l) + O_2(g) rightarrow 2H_2SO_4(aq) C)2KBr(aq) +Cl_2(g) rightarrow 2KCI(aq) + Br_2(l) C) 2KBr(aq) + Cl_2(g) rightarrow 2KCI(aq) + Br_2(l) D) CaBr_2(aq) + H_2SO_4(aq) rightarrow CaSO_4(s) + 2HBr(g) E) LiOH(aq) + HNO_3(aq) rightarrow LiNO_3(aq) + H_2O(l)Explanation / Answer
10) B) 82.6% . Percentage yield = the moles of bromomethane produced divided by moles of methanol reacted.
Moles of Ethanol = (5/32) and moles of 12.23 g bromomethane = (12.23/95)
11) D) 22.4g . Calcium is in excess here and 40g of V2o5 = 0.2197 moles react with calcium to produce 2 x (moles of V2o5 ) Vanadium = 0.4395 moles = 0.4395 x 52 g = 22.4g
12) E) Solute. Solute is the substance which is in the smallest proportion of the contents of a solution.
13) B) ionization. Ionization is the process of formation of ions from an ionic compound when it is dissolved in water.
14) E)NH3. KCL and HCL are strong electrolytes while Glucose and N2 are not electrolytes.
15) E)LiOH (aq) + HNO3 (aq) --> LiNO3 (aq)+ H2O (l) LiOH is a base and HNO3 is an acid and a reaction between these two is a nuetralization reaction which produces salt and water.