Answer: The kilograms of water must evaporate from 8kg of a 25% salt solution to produce 40% salt solution is 3 kg.
Explanation:
According to the ratio and proportion:

where,
= concentration of ist solution = 25%
= mass of ist solution = 8 kg
= concentration of second solution = 40%
= mass of second solution = ? kg


Thus the final solution must have a mass of 5 kg , i.e (8-5)= 3 kg of mass must be evaporated.
Therefore, the mass that must be evaporated from 8kg of a 25% salt solution to produce 40% salt solution is 3 kg.
Answer:
C. Solid
Explanation:
It's most about the kinetic energy, when molecules have the least amount of room to move around, they have the least amount of energy.
For example if you think about gas and how spread out the molecules are in order to evaporate, there it the highest amount of energy there.
The two properties which are used to define matter are that it has mass
and it takes up space. The other properties do not necessarily apply to
each matter. Such some matter can be a conductor of heat (such as metal)
and some not (such as non metals). Likewise, some matter can be buoyant
and float on liquid of density more than it but others would not on the
liquids of density less than it. In-fact not all the matters are
conductors of energy (such as heat, sound, electricity) or at-least a
very poor conductor of energy and tend to find application as
insulating agents (non conductors). So the only thing which is
necessarily true is that the matter would definitely have mass in even
their minutest form as atom and would take up some space.
<h2>Let us study about it .</h2>
Explanation:
Evaporation
It is the process of converting liquid into vapors .
Condensation
It is the process of converting vapors back into liquid state .
- Suppose if we have a sealed container and we are supplying it with no or little heat , we will see that as we increase heat , the particles starts moving faster .
- When they move they also colloide and transfer energies .
- The kinetic energies of certain molecule increase to an extent that they leave the other particles and escape in atmosphere .
- That is evaporation occurs .At the same time when these vapors collide with each other or with the walls of container they get cooled and again get converted to liquid state .
It is seen that a equilibrium is reached when "rate of evaporation becomes equal to rate of condensation ".