Question

Assuming an efficiency of 31.50 % calculate the actual yield of magnesium nitrate formed from 142.4 of magnesium and excess copper (II) nitrate

Mg + Cu(NO3)2 = Mg(NO3)2 +Cu

Answer 1

@Rushwr

Answer 2

Do u know how to get this ?

Answer 3

Efficiency = actual yield/ theoretical yield *100%

Answer 4

First we will have to find the theoretical yield first !

Answer 5

yh i got 5.841217606g for my actual yiel

Answer 6

oh let me check

Answer 7

but im stuck

Answer 8

where are u sucked?

Answer 9

im not sure what to do next, im trying to find the theoretical yield

Answer 10

i mean actual

Answer 11

the one i did was the theoretical i wrote actual

Answer 12

oh still wrong ! Wait. I'll tell u .

Answer 13

ok thanks

Answer 14

First u have to find a relationship between Mg and Mg(NO3)2 !
Cuz the information we know is about Mg right?

Answer 15

\(\color{blue}{\text{Originally Posted by}}\) @Rushwr
First we will have to find the theoretical yield first !
\(\color{blue}{\text{End of Quote}}\)

\[\frac{ actual }{ theoretical}*100 = percent, yield \]

Answer 16

to get the theoretical yield. i divided the grams which was given.... 142.4/ 24.31 (1mol (NO3)2/ 1mol of Mg

Answer 17

i then multiplied by 148.31 g/mol

Answer 18

As we can see in the equation the stoichiometric coefficients are 1:1 in Mg:Mg(NO3)3
That means 1 mole of Mg will form Mg(NO3)2
So the next we are doing is finding the moles of Mg present.
we know moles = mass divided by molar mass
\[n _{Mg} = \frac{ 142.4g }{ 24gmol ^{-1} }\]
Now we are gonna write the same equation for Mg(NO3)2
But here we don't know the mass, so we take the unknown mass as "x"
\[n _{Mg(NO3)_{2}} = \frac{ Xg }{ 148.3gmol ^{-1} }\]
As I told u earlier moles of Mg = moles of Mg(NO3)2
So we can equalize those 2 equation and find the theoretical mass of Mg(NO3)2 formed.
\[\frac{ 142.4 g}{ 24gmol ^{-1} } = \frac{ X g}{ 148.3gmol ^{-1} }\]
\[X= 880g \] Now this is the theoretical mass, but we have to find the actual yield .
\[efficiency = \frac{ actual yield }{ Theoretical yield } * 100%\]
\[actual yield = \frac{ Efficiency* theoretical yield }{ 100 } \]
\[Actual yield = \frac{ 31.5 * 880 }{ 100} = 277.2g\]
This is the answer I got. U better check my calculations. Others seems okai

Answer 19

I hope u got it @rachie19 :)

Answer 20

ok i understand what i did wrong. Thank you so much :)

Answer 21

Ur welcome !!! And no problem !