Answer: (3) silicon
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Silicon (Si)
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: ethane 
, propanone 
and water 
Answer:
Option-A. Covalent bonds would need to form between the molecules.
Explanation:
In given statement the molecules of 1-Butene are adding to each other forming a macromolecule called as Polybutene. Such type of reactions are called Polymerization reactions.
Polymerization reactions are those reactions in which small molecules called as monomers join together to form a large molecule also known as polymers. These reactions are done via different mechanisms like addition reaction, condensation reactions e.t.c.
Example:
Polybutene (polymer) is made up of 1-butene (monomers) through addition reaction in which the double bonds of 1-butene molecules are involved in the formation of new single covalent bond via acid catalyzed, base catalyzed or free radical mechanisms.
n H₂C=CH-CH₂-CH₃ → --[H₂C-CH(C₂H₅)]-n--
In above equation "n" represent large number, H₂C=CH-CH₂-CH₃ represent 1-Butene (monomer) and --[H₂C-CH(C₂H₅)]-n-- represent polybutene (polymer).
Answer:The kinetic-molecular theory of gases assumes that ideal gas molecules (1) are constantly moving; (2) have negligible volume; (3) have negligible intermolecular forces; (4) undergo perfectly elastic collisions; and (5) have an average kinetic energy proportional to the ideal gas's absolute temperature.
Explanation:
Answer:
A skateboarder coming down the ramp.
When something is going up against ( up or <u><em>down</em></u> ) something it causes friction.
Hope this helps!
Answer:
Explanation:
Salt water intrusion can cause the <u><em>fresh</em></u> water in wells to become contaminated with<u><em> salt</em></u>water.
