Question

Precious metals such as gold and platinum are sold in units of "troy ounces", where 1 troy ounce is 31.1 grams. If you have a block of platinum with a mass of 15,0 troy ounces, how many mole of the metal do you have? What is the size of the block in cubic centimeters ? (The density of platinum is 21.45 g/cm'at 20°C) (Atomic wt.of Pt. = 195)​

Answer 1

Answer:

i don't know if you have any questions

Answer 2

The moles of Platinum that we have is $2.392$ moles and the size of the block is $21.784$ $cm^{3}$

Explanation:

• Finding the moles of Platinum

According to the question,

$1$ troy ounce $= 31.1$ grams

Therefore, $15$ troy ounces = $15$ × $31.1$ $= 466.5$ grams

And, $Moles = \frac{Mass}{Molar mass}$

$Moles = \frac{466.5 }{195}$

⇒ Moles of Platinum $= 2.392$ moles

• Finding the size of the block in cubic centimeters

Density of Platinum $= 21.45$ g/cm³

$Density = \frac{Mass}{Volume}$

Therefore, $Volume = \frac{Mass}{Density}$

$Volume = \frac{466.5}{21.45}$

⇒ Volume $= 21.748$ cm³

Hence, the size of the block in cubic centimeters is $21.748$.