Answer:
5
Explanation:
just subtract 20-25 and 5 is left over which is how much the water when up with the rock.
Answer:
The difference in the number of protons and neutrons in atoms account for many of the different properties of elements.
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.
Explanation:
the lone pairs will be negatively charged. these have a repulsion effect on other negatively charged electrons in the shells of atoms. picture a water molecule: the lone electron pair on the top of the oxygen will have a repulsion force on the 2 hydrogen atom's orbiting electrons to cause a bent molecular geometry.