If we double the mass of an object without a change in volume, its density would be A) half.
B) double.
C) unchanged.

The formula for density is
density
=
mass
volume
.
We need to double the volume, i.e. multiply it by
2
.
But in order to multiply one side of the equation by a number, the same has to be done to the other side.
Multiplying the volume by
2
is the same as multiplying the fraction
mass
volume
by
1
2
.
So let's multiply both sides of the equation by
1
2
:
⇒
1
2
×
density
=
1
2
×
mass
volume
⇒
density
2
=
mass
2
×
volume
Therefore, doubling the volume results in the density being halved.

Half