density question set up
Chemistry

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sylvanite is a mineral that contains 28.0% gold by mass. When 171 grams of sylvanite is added to a graduated cylinder contains 155 mL of water, the water level in the cylinder rose to 205mL. By how many milliliters did the gold increase the volume of water?".
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Sylvanite is 28.0% gold = 28 g out of 100 g is gold
28 / 100 = x / 171
171 g of Sylvanite contains 47.88 g of gold
Water displacement: 155 mL to 205 mL = + 50 mL
171 g Sylvanite displaces 50 mL H_{2}O
If I understand this correctly, the Q is how much displacement due to the gold content only
Well, that would be 28.0% of the total displacement, i.e.
(50 mL)(.28) = 14 mL H_{2}O displaced due to gold content alone
Or you could take the roundabout way, as in
X / 50 = 47.88 / 171 x = 14
Please let me know if you need any clarification. I'm always happy to answer your questions.
My text states the density of gold is 19.3 g/mL. So would I have to divide the 171 grams of sylvanite by the gold density first?
That is the density of gold, yes. However, the question above asks how much water was displaced due to the gold content in the Sylvanite. The answer is 14 mL (28%) out of the 50 mL was displaced due to the gold content. I'm not clear on where density comes into the game. Is there a second part to this question?
The entire question reads:
sylvanite is a mineral that contains 28.0% gold by mass. When 171 grams of sylvanite is added to a graduated cylinder containing 155 mL of water, the water level in the cylinder rose to 205mL. By how many milliliters did the gold increase the volume of water?" See attached density table...
Sylvanite does not appear on density table only gold with a value of 19.3g/mL. table2.9.pdf
Im guessing added information to confuse me? below is what i did with the problem to solve. I'm pretty sure I am way off.
let's see...
50 mL displaced by 171 g of mixed compound (47.88 g gold + 123.12 g unknown)
gold: 19.3 g/mL = 47.88 g / x mL > 2.48 mL displaced due to the gold content
leaves 123.12 g / 47.52 mL = 2.59 g/mL glass has a density of 2.6 g/mL
that may be your mystery compound
in my first answer I assumed equal density, that's how I came up with 14 mL
since they stretch 'mixed compound' and the density of gold... we assume different densities, ergo, see above
actually, I went diggin':
Sylvanite: AgAuTe4, Silver Gold Telluride, three different densities involved...
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