Sugar dissolves faster in hot water than it does in cold water because hot water has more energy than cold water. when water is heated, the molecules gain energy and because of that, move faster. as they move faster, they come in contact with the sugar more often, causing it to dissolve faster.
The less soluble salt : PbCl₂
<h3>Further explanation</h3>
Given
0.1 M NaCl
Required
The less soluble salt
Solution
If we see from the answer option, the salt that is more difficult to dissolve in NaCl is PbCl₂ because it has the same ion (Cl)
When PbCl₂ is dissolved in water, ionization will occur
PbCl₂ ⇒ Pb²⁺+ 2Cl⁻
So, when dissolved in NaCl, NaCl itself will be ionized
NaCl ⇒ Na⁺ + Cl⁻
Based on the principle of equilibrium, the addition of an ion (one of the ions is enlarged), the reaction will shift towards the ion that was not added. In addition to this Cl ion, the reaction will shift to the left so that the solubility of PbCl₂ will decrease (the reaction to the right decreases)
So basing on my understanding of this so far, an atom is an element that has the same number of protons and neutrons, an ion is an element that has different numbers of protons and electrons, an ion is positive when it has more protons than electrons and negative when it has more electrons than ions .
2+8+2+4+7=23, i think that should be the answer just add everything and multiply if you have to