from the balanced equation moles of ZnCl2 = moles of Zn moles of ZnCl2 = mass /
ID: 700656 • Letter: F
Question
from the balanced equation moles of ZnCl2 = moles of Zn
moles of ZnCl2 = mass / molar mass
= 0.0909 / 136.28
= 6.67 x 10^-4
moles of Zn = 6.67 x 10^-4
mass of Zn = moles x molar mass
= 6.67 x 10^-4 x 65.39
= 0.04362
a)
%Zn = ( mass of Zn / total mass ) x 100
=( 0.04362 / 0.5031 ) x 100
= 8.67 %
% Cu = 100 - 8.67
= 91.3 %
b)
this could be checked out by measuring melting points of metals . here Zn only react with HCl that means after the reaction total Zn is react with HCl . now the filtrated is carefully seperated by filtration method the metal is dried and measured melting point . the metal which is remians is Cu its melting point is we can find any standard books and the solution contain zinc. this solution is treated with coke and we get zinc metal this can again filtrated and dried the metal by measuing this metal melting point we get zinc meltaing point .
Explanation / Answer
Help Commercial brass, an alloy of Zn and Cu, reacts with hydrochloric acid as follows Zn(s) + 2 HCl(aq) ZnCl2(aq) + H2(g) (Cu does not react with HCI.) When 0.5031 g of a certain brass alloy is reacted with excess HCI, 0.0909 g Zncl2 is eventually isolated. (a) What is the composition of the brass by mass? 96Zn %Cu | b) How could this result be checked without changing the above procedure? This answer has not been graded yet
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.