Ah, stoichiometry. Have you ever done ratios before?
When you are given chemical reactions, all of the moles of reactant and product are proportional. This means that they're in ratio. Say we double the number of moles of water to 12 moles. How many moles do you think C2H6 will have? It'd be 4 moles, since just like water it was doubled since they're in proportion.
You can also think about that example above like a literal ratio. Since the original ratio is 2:6, it then turns into n:12, with n being the unknown number of moles of C2H6. Since ratios we know that ratios are always equal can be converted to fraction:
2/6 = n/12
Cross multiply:
24 = 6n
n = 4 moles
Makes sense? On to the actual question.
We're looking at the proportion between oxygen and carbon dioxide. Let's write that into a ratio:
7:4
Since there are seven moles of oxygen and four moles of carbon dioxide.
The number of moles of carbon dioxide is reduced to 1 mole. You could simply divide seven by 4 to find your answer (Since 4 was divided by 4 to make 1), but let's use the ratio method just in case questions in the future aren't this convenient:
7:4 becomes n:1
Convert to fraction:
7/4 = n/1
Cross multiply;
7 = 4n
Divide:
n = 7/4
Convert to decimal:
n = 1.75
The answer is Option C, 1.75 moles.
Let me know if you want me to explain anything I did here.
Good luck!
-T.B.
Answer: The formula of the acid that was neutralized is 
Explanation:
Neutralization is a chemical reaction in which acid and base combine to form salt and water. Acids donate
and bases donate
in water which combine to form water molecules.
As the salt formed is
, the acid must contain
and thus the acid is 
The balanced chemical reaction is ;

The formula of the acid that was neutralized is 
False. An unbalanced force can change the direction in which an object is moving.
Answer:
2HCI + Na2S ----> H2S + 2NaCl
Explanation:
For a balanced chemical equation, the number of moles of atoms on the reaction side must equal the number of moles of atoms on the product side, in accordance with the law of conservation of mass.
The correct answer is:
2HCI + Na2S ----> H2S + 2NaCl
Since it has equal number of moles of each atom on both sides of the equation: 2 atoms each of hydrogen, chlorine, and sodium on both sides of the equation as well as 1 atom of sulphur on both sides of the equation.