CHem

posted by .

Sterling silver is a mixture of silver and copper having a mole ration of silver to copper equal to 7.8 what is the mass percent composition of this mixture?

Ok I know the answer to this and I know how its done: 1 mol Cu weighs 63.5 g
7.8 mol Ag weigh 7.8(107.87)= 841g what i don't understand is why is the 7.8 multiplied with grams of Ag and not Cu?

  • CHem -

    mol ratio Ag/Cu = 7.8 which means
    Ag = 7.8*Cu which means
    that the Ag is whatever the Cu is times 7.8 (Ag is the larger component). OR, said another way,
    7.8 mols Ag to 1 mol Cu; then
    7.8(107.87)g Ag to 63.546 g Cu.
    I get %Ag = almost 93% and Cu slightly more than 7%
    I think Sterling silver is supposed to be 92.5% Ag to 7.5% Cu.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. AP Chem

    A silver-copper alloy had a mass of 0.1264g. When the alloy was dissolved in nitric acid and the silver precipitated as silver chloride, the precipitate had a mass of 0.1375g. Calculate the percent of silver in the alloy. Show your …
  2. Chem answer check

    Does this look correct? Thx! Write the balanced equation for the reaction between solid copper and silver nitrate, that produces solid silver and copper(II) nitrate in solution. Include your experimentally determined mole ratios for
  3. chemistry

    Sterling silver, an alloy of silver and copper, contains 7.5 percent copper by mass and has a density of 10.3 g/cm3. How many copper atoms are in a sterling silver sphere whose radius is 2.0 in?
  4. chem

    a 6.54 g sample consisting of a mixture of silver nitrate and sodium nitrate is dissolved in water. this mixture then reacts with barium chloride to for 3.50 g of silver chloride. calculate the percent by mass of silver nitrate in …
  5. algebra

    British sterling silver is a copper-silver alloy that is 7.5% copper by weight. How many grams of pure copper and how many grams of British sterling silver should be used to prepare 170 grams of a copper-silver alloy that is 16% copper …
  6. Chemistry

    A mixture contains only CuCl2 and FeCl3. A 0.7391 g sample of the mixture is completely dissolved in water and treated with silver nitrate. if 86.91 mL of 0.1463 M silver nitrate soultion is needed to precipitate all the chloride as …
  7. Chemistry AP

    I'm using Zumdahl 7th Edition Chemistry Book and I'm having trouble with some practice problems in the first chapter. Here are a few: 87: Sterling silver is a solid solution of silver and copper. If a piece of a sterling silver necklace …
  8. algebra

    British sterling silver is a copper-silver alloy that is 7.5% copper by weight. How many grams of pure copper and how many grams of British sterling silver should be used to prepare 320 grams of a copper-silver alloy that is 20% copper …
  9. chemistry

    A mixture of 3.00 g of silver and copper metals was dissolved in excess nitric acid. Resulting salts, silver(I) nitrate and copper(II) nitrate, were isolated and dissolved in enough water to make 0.100 L of a solution with a total …
  10. Math

    British sterling silver is a copper-silver alloy that is 7.5% copper by weight. How many grams of pure copper and how many grams of British sterling silver should be used to prepare 200 grams of a copper-silver alloy that is 10% copper …

More Similar Questions