Answer:density
=
2.9
g/cm
3
Explanation:
We're asked to find the density of the rock, given some mass and volume information.
We're given that the mass of the system before the rock was added was
120
g
. The mass after the rock was added was
250
g
, so the rock's mass is
m
rock
=
m
final
−
m
initial
=
250
l
g
−
120
l
g
=
130
l
g
−−−−−
The initial volume of water in the graduated cylinder was
30
mL
, and the volume after the rock was added read
75
mL
, so the rock's volume is
V
rock
=
V
final
−
V
initial
=
75
l
mL
−
30
l
mL
=
45
l
mL
−−−−−−
The equation for the density of the rock is
density
=
mass
volume
And so we have
density
=
130
l
g
45
l
mL
=
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
∣
∣
∣
2.9
l
g/mL
=
2.9
l
g/cm
3
∣
∣
∣
−−−−−−−−−−−−−−−−−−−−−−−−−
Step-by-step explanation: