Question

molar mass worksheet
calculate the molar masses of the following chemicals:

1. cl₂ 8) uf₆
2. koh 9) so₂
3. becl₂ 10) h₃po₄
4. fecl₃ 11) (nh₄)₂so₄
5. bf₃ 12) ch₃cooh
6. ccl₂f₂ 13) pb(no₃)₂
7. mg(oh)₂ 14) ga₂(so₃)₃

Explanation:

Step1: Recall the atomic masses

• Atomic mass of \(Cl = 35.45\space g/mol\), \(K=39.10\space g/mol\), \(O = 16.00\space g/mol\), \(H=1.01\space g/mol\), \(Be = 9.01\space g/mol\), \(Fe=55.85\space g/mol\), \(B = 10.81\space g/mol\), \(F=19.00\space g/mol\), \(C = 12.01\space g/mol\), \(Mg = 24.31\space g/mol\), \(U=238.03\space g/mol\), \(S = 32.07\space g/mol\), \(P=30.97\space g/mol\), \(N = 14.01\space g/mol\), \(Pb=207.2\space g/mol\), \(Ga = 69.72\space g/mol\)

Step2: Calculate molar mass for \(Cl_{2}\)

Molar mass \(M(Cl_{2})=2\times35.45\space g/mol = 70.90\space g/mol\)

Step3: Calculate molar mass for \(KOH\)

\(M(KOH)=39.10 + 16.00+1.01=56.11\space g/mol\)

Step4: Calculate molar mass for \(BeCl_{2}\)

\(M(BeCl_{2})=9.01+2\times35.45 = 9.01 + 70.90=79.91\space g/mol\)

Step5: Calculate molar mass for \(FeCl_{3}\)

\(M(FeCl_{3})=55.85+3\times35.45=55.85 + 106.35 = 162.20\space g/mol\)

Step6: Calculate molar mass for \(BF_{3}\)

\(M(BF_{3})=10.81+3\times19.00=10.81+57.00 = 67.81\space g/mol\)

Step7: Calculate molar mass for \(CCl_{2}F_{2}\)

\(M(CCl_{2}F_{2})=12.01+2\times35.45+2\times19.00=12.01 + 70.90+38.00=120.91\space g/mol\)

Step8: Calculate molar mass for \(Mg(OH)_{2}\)

\(M(Mg(OH)_{2})=24.31+2\times(16.00 + 1.01)=24.31+2\times17.01=24.31+34.02 = 58.33\space g/mol\)

Step9: Calculate molar mass for \(UF_{6}\)

\(M(UF_{6})=238.03+6\times19.00=238.03+114.00 = 352.03\space g/mol\)

Step10: Calculate molar mass for \(SO_{2}\)

\(M(SO_{2})=32.07+2\times16.00=32.07 + 32.00=64.07\space g/mol\)

Step11: Calculate molar mass for \(H_{3}PO_{4}\)

\(M(H_{3}PO_{4})=3\times1.01+30.97+4\times16.00=3.03+30.97+64.00 = 98.00\space g/mol\)

Step12: Calculate molar mass for \((NH_{4})_{2}SO_{4}\)

\(M((NH_{4})_{2}SO_{4})=2\times(14.01 + 4\times1.01)+32.07+4\times16.00=2\times(14.01+4.04)+32.07 + 64.00=2\times18.05+32.07+64.00=36.10+32.07+64.00 = 132.17\space g/mol\)

Step13: Calculate molar mass for \(CH_{3}COOH\)

\(M(CH_{3}COOH)=2\times12.01+4\times1.01+2\times16.00=24.02+4.04+32.00 = 60.06\space g/mol\)

Step14: Calculate molar mass for \(Pb(NO_{3})_{2}\)

\(M(Pb(NO_{3})_{2})=207.2+2\times(14.01+3\times16.00)=207.2+2\times(14.01 + 48.00)=207.2+2\times62.01=207.2+124.02=331.22\space g/mol\)

Step15: Calculate molar mass for \(Ga_{2}(SO_{3})_{3}\)

\(M(Ga_{2}(SO_{3})_{3})=2\times69.72+3\times(32.07+3\times16.00)=139.44+3\times(32.07+48.00)=139.44+3\times80.07=139.44 + 240.21=379.65\space g/mol\)

Answer:

1. \(70.90\space g/mol\)
2. \(56.11\space g/mol\)
3. \(79.91\space g/mol\)
4. \(162.20\space g/mol\)
5. \(67.81\space g/mol\)
6. \(120.91\space g/mol\)
7. \(58.33\space g/mol\)
8. \(352.03\space g/mol\)
9. \(64.07\space g/mol\)
10. \(98.00\space g/mol\)
11. \(132.17\space g/mol\)
12. \(60.06\space g/mol\)
13. \(331.22\space g/mol\)
14. \(379.65\space g/mol\)