Answer:
C) Covalent bonds come about because of a sharing of electrons; ionic bonds do not.
Explanation:
There are two main types of chemical bonds- covalent and ionic/electrovalent bonds.
Ionic bond: Ionic or electrovalent bonds are characterized by the transfer of electrons from electropositive atoms (metals) to electronegative atoms (non-metals). The metal atoms after donating their electrons become positively charged ions (cations) while the non-metal atoms after accepting electrons become negatively charged ions (anions). Strong electrostatic forces of attraction constitutes ionic bonds.
Covalent bond: Covalent bonds are formed by the sharing of electrons by the atoms involved in the bond; usually between atoms of comparable electronegativities or atoms of the same element. The shared electrons are contributed by each of the atoms involved in the bonding or may be contributed by only one of the atoms. In covalent bonding, molecules rather than ions are formed.
Answer:
<em>Most fire extinguishers work by separating the fuel from the oxygen. The oxygen comes from the air. It is the same oxygen we breathe. Since the oxygen has to be in contact with the fuel, if you can coat the fuel with something that keeps the oxygen away, the fire will go </em><em>out.</em><em> </em><em>S</em><em>ome </em><em>ways </em><em>of </em><em>using </em><em>fire </em><em>extinguisher </em><em>are:</em>
- <em> Water extinguishers work mainly by cooling (removing heat), but a dense spray of water droplets also helps to cut off oxygen. </em>
- <em> Dry powder extinguishers soak up heat, melt on the fuel, and cut off oxygen, but they also neutralize the </em><em>fuel</em><em> (cutting it off from the </em><em>fire)</em><em> </em><em>.</em>
Explanation:
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