Question

22. Silver and gold has a density of 10.5 g/cm3 and 19.3 g/cm3, respectively. Which would have a lesser mass, 5 cm3 Ag or 5 cm3 Au?

Answer 1

Answer:

Density =

Mass

Volume

Thus

Mass

=

Density

(

ρ

)

×

volume

Mass of silver

=

10.5

⋅

g

⋅

c

m

−

3

×

5

⋅

c

m

3

=

52.5

⋅

g

.

Mass of gold

=

19.3

⋅

g

⋅

c

m

−

3

×

5

⋅

c

m

3

≅

100

⋅

g

.

Note that I solved this problem dimensionally. I wanted an answer in grams; after cancelling out the units, I manifestly got an answer in grams. This is a check on whether I divided, multiplied, added correctly. It is all too easy to make an error.

Answer 2

$\huge\red{Answer}$

Clearly, the gold will have a greater mass, as it has a greater density.

Explanation:

Density = MassVolume

Thus Mass = Density(ρ)×volume

Mass of silver = 10.5⋅g⋅cm−3×5⋅cm3 = 52.5⋅g.

Mass of gold = 19.3⋅g⋅cm−3×5⋅cm3 ≅ 100⋅g.

Note that I solved this problem dimensionally. I wanted an answer in grams; after cancelling out the units, I manifestly got an answer in grams. This is a check on whether I divided, multiplied, added correctly. It is all too easy to make an error.