Moles= grams of compound/molar mass of compound ??
Answer:
There was a change in temperature on the surface you were walking on. It is possible that "you" were walking on cool, wet sand and when your parents said it was time to leave, you ran barefoot towards the parking lot (away from the sand) and got a burning coal sensation on your feet.
Explanation:
Answer: 1. C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur
2. B) 
3. B) Fluorine
Explanation:
1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.
Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7
Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.
2. A molecular compound is usually composed of two or more nonmetal elements. Example:
Ionic compound is formed by the transfer of electrons from metals to non metals. Example:
,
and 
3. For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas 
Answer: I & III
Explanation: Solutes are the substances which are minimum in quantity and which is required to dissolve in the solvent (which is larger in quantity) in order to make a solution.
In the asked question, it is given that the water is the solvent and from the given solutes we have to pick which would make an aqueous solution with the highest concentration of solute possible.
Thus the most appropriate answers could be the Ammonia and hexanol which can make the highest possible concentration of solute as ammonia is the gas which is highly soluble in water and hexanol is an alcohol which has an affinity for water. Thus the correct option is I & III