Calculation of mass %

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Ghosty
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Calculation of mass %

Post by Ghosty »

Mixture A consists of 0.306g Al, 2.376g Ag and 3.726g Pb. Add mixture A to Cu(NO3)2 solution. After the reaction was completed, 6.046g of solids were obtained B. Calculate the mass % of the substances in B.
C%= (gram of the element / gram of all mixture) x 100%
help is very appreciated
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ChenBeier
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Re: Calculation of mass %

Post by ChenBeier »

Aluminium and lead and Cu(NO3)2 will give Copper precipitate.
So the remaining contain Cu and still Ag.
Calculate the mass of Cu
Ghosty
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Re: Calculation of mass %

Post by Ghosty »

Sir sorry for the trouble but can you explain it a bit more ,not a very bruh student 😅😅 :oops:
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ChenBeier
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Re: Calculation of mass %

Post by ChenBeier »

If you check a table of redoxpotentials you will find that aluminium -1,662 V and also lead -0,14 V have negative values . The only positiv one is silver +0,799 V. Copper +0,342 V also have a positiv value, but its smaller then silver. So copper nitrate can react with aluminium and lead and will be precipitate, the masses of Al and Pb are not important, because they will be dissolved.
You will have a remaining mixture of Cu and Ag.
The mass of the mixture is given and also the mass of silver. The difference of both will give the mass of copper.
The quote of mass copper to mixture will give the percentage.
Ghosty
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Re: Calculation of mass %

Post by Ghosty »

thanks a lot sir, Always a huge help :)
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