Need help asap! 1. Given that the electronegativity of sulfur (S) is 2.5 and that of silicon (Si) is 1.8, which of the following best describes the chemical bonding in silicon monosulfide (SiS)?
A. ionic: transfer of electrons from silicon to sulfur
B. nonpolar covalent: equal sharing of electrons between silicon and sulfur
C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur
D. polar covalent: electrons shared between silicon and sulfur but attracted more to the silicon

2. Which of the following is a molecular compound?

A. Mg3N2
B. NH3
C. AlCl3
D. LiBr

3. Potassium (K) reacts with a certain nonmetallic element (Z) to form a compound with the general formula KZ; where element Z is a diatomic gas at room temperature. What is element Z?

A. Oxygen
B. Fluorine
C. Nitrogen
D. Hydrogen

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

1. they vary with a higher number because boiling is way hotter than melting

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.