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 
Explanation:
As it is known that in solids, molecules are held together because of strong intermolecular forces of attraction. As a result, they are held together and have definite shape and volume.
Whereas in liquids, molecules are not held so strongly as they are in solids. Hence, they move from their initial position and they do not have definite shape but they have definite volume.
Liquids obtain the shape of container in which they are kept.
In gases, molecules are held together by weak intermolecular forces. As a result, they move far apart from each other and occupy the space of a container or vessel in which they are placed.
The physical state (at room temperature) of the following are determined as follows:
(a) Helium in a toy balloon : Helium at room temperature exists as a gas. So, when helium is present in a toy balloon then it acquires the volume of toy balloon.
(b) Mercury in a thermometer : Mercury at room temperature exists as a liquid. When it is placed in a thermometer then volume of mercury does not get affected.
(c) Soup in a bowl : Since, soup is a liquid. Hence, its volume will not change according to the volume of container.
Answer:
The weight of the Astroturf is 179,684.31 Newtons.
Explanation:
Length of a soccer field = 0.06214 mile = 328.0992 feet
(1 mile = 5280 feet)
Breadth of a soccer field = 253 feet
Length of a Astroturf which soccer field is to be covered, l = 328.0992 feet
Breadth of a Astroturf which soccer field is to be covered ,b = 253 feet
Thickness of a Astroturf with which soccer field is to be covered = h
h = ½ inch = 0.5 inch = 0.041665 feet
(1 inches = 0.08333 feet)
Volume of the Astroturf ,V= l × b × h
Mass of the Astroturf = m
Density of the Astroturf = d = 187 
1 oz = 0.0283495 kg
Weight of the Astroturf = W
W = mg
The weight of the Astroturf is 179,684.31 Newtons.
Hey there!:
density = 3.51 g/cm³
Volume = 0.0270 cm³
Therefore:
D = m / V
3.51 = m / 0.0270
m = 3.51 * 0.0270
m = 0.09477 g
