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 
If the crucible wasn't covered with a lid the reactants may have produced a gas that was released into the surroundings, or mass may have been lost in the form of water vapour.
he total number of each of the atoms on the left and the right are the same thus the reaction equation is balanced.
<h3>What is the law of conservation of mass?</h3>
The law of conservation of mass states that, mass can neither be created nor destroyed. In view of the law of conservation of mass, the total mass of the reactants on the left-hand side must be the same as the total mass of products at the right hand side.
Thus is the total mass of the reactants and the products are not the same, it then follows that the reaction does not demonstrate the law of conservation of mass. In this case, the total number of each of the atoms on the left and the right are the same thus the reaction equation is balanced.
Learn more about conservation of mass:brainly.com/question/13383562
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The two types of energy changes that occur are heat and light changes.
According to Raoult's law, Vapor pressure is directly proportional to the mole fraction of the solution. As 1.0 M CaF2 has least moles here, it has lowest vapor pressure.
In short, Your Answer would be Option D
Hope this helps!
