• Mar 6th 2013, 12:32 AM
NettieL
just a little rusty on the conversion side of maths at the moment, so was wondering about this question:

'An ice cube is 2.00 in. on a side and weighs 1.2*10^2 grams.

a) what is the density of the ice?
b) what volume of water (d=1.00g/ml) is obtained when the ice cube melts?'

I have attempted part a, but never got the real answer (which is 0.916g/cm^3)

so here is what I was starting:
d=mass/vol.

mass = 1.20*10^2g

converting in. to cm: 1in. = 2.54cm
therefore 2in. * (2.54cm/1in.) = 5.08 cm.

therefore vol.= pi(5.08)^2(5.08)
= 411.85

so d=mass/vol.

1.20*10^2g/411.85=0.291

I don't know what I have messed up, but if someone could help me understand, that would be appreciated!!
• Mar 6th 2013, 12:39 AM
BobP
It's an ice CUBE.
• Mar 6th 2013, 12:50 AM
NettieL
so where should I 'cube' it?
• Mar 6th 2013, 12:57 AM
BobP
A cube is a particular sort of rectangular solid, $\pi$ does not come into the calculation of its volume.
• Mar 6th 2013, 01:08 AM
NettieL
isn't the formula for the volume of a container V=pi(r^2)h?
• Mar 6th 2013, 01:15 AM
BobP
That's the formula for the volume of a cylinder radius r and height h, not a cube.
• Mar 6th 2013, 01:40 AM
NettieL