Answer:
to protect peoples teeth against cavities
Explanation:
i just know
Answer:
B. Carbon shares 2 pair of electrons with each oxygen.
Explanation:
- Carbon dioxide is formed from combustion reactions, which involves a reaction between carbon and oxygen gas.
- Carbon dioxide molecule is formed from one carbon atom and two oxygens. As an element, carbon only has 4 outer shell electrons and oxygen 6.
- The two atoms require to gain electrons to achieve a stable configuration; carbon require to gain four electrons and oxygen requires two electrons.
- Double covalent bonds form between the atoms, where two electrons from each atom are shared making 4 bonding electrons in total.
Hope it helped!
Evaporation is called a surface phenomenon because water molecules present on the surface of liquid are bonded weakly as compared to inner molecules and when temperature increase hydrogen bonding between molecules break .Due to this water molecules tend to evaporation so that's why evaporation called the surface phenomenon.
Answer:
A. 2 Fe, 3 S and 12 O
B. 43 moles of H
C. 1.0×10² moles of C
Explanation:
A. Formula for iron (III) sulfate is Fe₂(SO₄)₃
This salt has 2 atoms of iron and 3 sulfates, so in total we have:
2 Fe, 3 S and 12 O
Pay attention to the subscripts
B. Formula for quinine is: C₂₀H₂₄N₂O₂
If we continue with the example before we can say that 1 mol of Iron (III) sulfate contains 2 moles of Fe, 3 moles of S and 12 moles of O
Then, 1 mol of quinine contains 24 moles of H
So 1.8 moles of quinine, may contain (1.8 . 24) /1 = 43 moles of H
C. 1 mol of quinine contains 20 moles of C
5.4 moles of quinine may contain (5.4 . 20) /1 = 1.0×10²
<u>(As the answer must be in 2 significant figures and the real answer is 108, I had to use scientific notation)</u>
