Ice floats after it crystallizes because ITS DENSITY IS LESS THAN THAT OF WATER.
When a quantity of water is cools down by reducing its temperature, the molecules of the water lose kinetic energy and slow down in their movement. As the water is cooling down, it is volume is expanding. When the temperature reaches zero degree Celsius, the water becomes ice. At this point, the ice can float on water because its density is less than that of water; this is as a result of the spaces that now exist in the ice structure.
<u>Answer:</u> The entropy change of the process is 
<u>Explanation:</u>
To calculate the entropy change for different phase at same temperature, we use the equation:

where,
= Entropy change
n = moles of acetone = 6.3 moles
= enthalpy of fusion = 5.7 kJ/mol = 5700 J/mol (Conversion factor: 1 kJ = 1000 J)
T = temperature of the system = ![-94.7^oC=[273-94.7]=178.3K](https://tex.z-dn.net/?f=-94.7%5EoC%3D%5B273-94.7%5D%3D178.3K)
Putting values in above equation, we get:

Hence, the entropy change of the process is 
Explanation:
The given data is as follows.
P = 3 atm
=
= 
= 9 L =
(as 1 L = 0.001
),
= 15 L = 
Heat energy = 800 J
As relation between work, pressure and change in volume is as follows.
W = 
or, W = 
Therefore, putting the given values into the above formula as follows.
W = 
= 
= 1823.85 Nm
or, = 1823.85 J
As internal energy of the gas
is as follows.
= Q - W
= 800 J - 1823.85 J
= -1023.85 J
Thus, we can conclude that the internal energy change of the given gas is -1023.85 J.
The most likely formula for an oxide formed between group 1a atom X and oxygen would be
X2O. - X is group 1a atom.
Iron is left in the filter and salt solution (salt and water) passes into the cup.
Hope it helps