Answer: C) Non-metals can share pairs of electrons and form covalent bonds
Explanation: The principal reason why it is non-metals that can form covalent bonds is because of their electronegativities. Electronegativity is the tendency of an atom to attract electrons towards itself.
The participating atoms in a covalent bond have to be able to hold the shared electron in place & it is this attraction towards the centre of each participating atom that holds the electrons in place. Metals aren't electronegative, they don't attract electrons towards each other, they'd rather even push the electrons away from themselves (electropositive) to be stable. The closest concept of metals to shared electrons is in metallic bonding, where metals push and donate their valence electrons to an electron cloud which is free to move around the bulk of the metallic structure. But this is nowhere near the type of bonding that exist in covalent bonds.
Answer & Explanation:
In physics, a contact force is a force that acts at the point of contact between two objects, in contrast to body forces. Contact forces are described by Newton's laws of motion, as with all other forces in dynamics. Contact force is the force in which an object comes in contact with another object. Contact forces are also direct forces. Contact forces are ubiquitous and are responsible for most visible interactions between macroscopic collections of matter. Pushing a car up a hill or kicking a ball or pushing a desk across a room are some of the everyday examples where contact forces are at work. In the first case the force is continuously applied by the person on the car, while in the second case the force is delivered in a short impulse.
<span>So when the chemist combines Ethane (CH3CH3) and Chlorine (Cl2) with the intention of producing Chloroethane (CH3CH2Cl), the other product that's formed in this reaction is 1,2-dichloroethane (ClCH2CH2Cl) also called as Ethylene dichloride with molecular weight of 98.954 g/mol. This is a colorless oily flammable substance that weighs heaver when vaporized.</span>
C + O2= CO2



CO2 is limit
5.4-3.72= 1.68 g of C is excess
5.4 g = 100%
3.72 g = x
x=68.9 %