Answer:
Explanation:
1. find the molar mass (amu) of each element and add them to get the whole molar mass.
2. divide the 1 element molar mass with the whole molar mass
3. multiple by 100 and that gives you the % composition.
<h2><u><em>56-57: NaCl</em></u></h2>
1. Na(22.99amu) + Cl (35.453amu)=58.443
2(Na):
= .393
2(Cl):
= .607
3(Na): .393 * 100=39.3%
3(Cl): .607 * 100= 60.7%
<h2><u>58-60 </u>

<u /></h2>
1. K: (39.098)(2)=78.196
_ C: (12.011)(1)= 12.011
_O: (15.99)(3) = 47.997
78.196+12.011+47.997= 138.204
2:K:
= .566 <u>Step </u>3: (.566)(100)= 56.6%
2: C:
= .087 <u>Step 3</u>: (.087)(100)= 8.7%
2: O:
= .347 <u>Step 3</u>: (.347)(100) = 34.7%
<h2>
61-62 
</h2>
1. Fe (55.845)(3)= 167.535
_ O (15.999)(4) = 63.996
167.535+63.996=231.531
2: Fe:
= .724 Step 3: (.724)(100)= 72.4%
2: O :
= .276 Step 3: (.276)(100) = 27.6%
<h2>63-65

</h2>
1.
C(12.011*3)=36.033
H(1.008*5)=5.04 + (1.008*3)=3.024 so its 8.064
O(15.999*3)=47.997
add them: 92.094
2: C:
= .391 Step 3: (.391)(100) = 39.1%
2: H:
= .088 step 3: (.088)(100) = 8.8%
2: O:
= .521 step 3: (.521)(100) = 52.1%
The answer is (4) heptane. Saturated hydrocarbon means that there is no double bonds between the carbon atoms. For propene and butene, there is double bond. For ethyne, there is triple bond.
answer : 14 J/mol
J/mol unit in the answers gives the hint as to what you should do which is divide the J from mol
J ÷ mol
84 ÷ 6 = 14