Respuesta :
Answer:
A)Molecular formula of ibuprofen is[tex]C_{13}H_{18}O_2[/tex]
B)Molecular formula of Cadaverine is [tex]C_{5}H_{14}N_2[/tex]
C)Molecular formula of Epinephrine is [tex]C_9H_{13}O_3N_1[/tex]
Explanation:
Percentage of an element in a compound:
[tex]\frac{\text{Number of atoms of element}\times \text{Atomic mass of element}}{\text{molecular mass of element}}\times 100[/tex]
A) Ibuprofen, a headache remedy, contains 75.69% C, 8.80% H, and 15.51% O by mass.
Molar mass of ibuprofen = 206 g/mol.
Let the molecular formula of ibuprofen be =[tex]C_xH_yO_z[/tex]
Number of carbon atoms in 1 molecule of ibuprofen ;
[tex]75.69\%=\frac{x\times 12 g/mol}{206 g/mol}\times 100[/tex]
[tex]x=\frac{75.69\times 206 g/mol}{100\times 12 g/mol}=12.99\approx 13[/tex]
Number of hydrogen atoms in 1 molecule of ibuprofen ;
[tex]8.80\%=\frac{y\times 1 g/mol}{206 g/mol}\times 100[/tex]
[tex]y=\frac{8.80\times 206 g/mol}{100\times 1 g/mol}=18.12\approx 18[/tex]
Number of oxygen atoms in 1 molecule of ibuprofen ;
[tex]15.51\%=\frac{z\times 16 g/mol}{206 g/mol}\times 100[/tex]
[tex]z=\frac{15.51\times 206 g/mol}{100\times 16 g/mol}=1.99\approx 2[/tex]
Molecular formula of ibuprofen :
= [tex]C_xH_yO_z= C_{13}H_{18}O_2[/tex]
B) Cadaverine contains 58.55% C, 13.81% H, and 27.40% N by mass
Molar mass of Cadaverine = 102.2 g/mol.
Let the molecular formula of Cadaverine be =[tex]C_xH_yN_z[/tex]
Number of carbon atoms in 1 molecule of Cadaverine ;
[tex]58.55\%=\frac{x\times 12 g/mol}{102.2 g/mol}\times 100[/tex]
[tex]x=\frac{58.55\times 102.2 g/mol}{100\times 12 g/mol}=4.98\approx 5[/tex]
Number of hydrogen atoms in 1 molecule of Cadaverine ;
[tex]13.81\%=\frac{y\times 1 g/mol}{102.2 g/mol}\times 100[/tex]
[tex]y=\frac{13.81\times 102.2 g/mol}{100\times 1 g/mol}=14.11\approx 14[/tex]
Number of nitrogen atoms in 1 molecule of Cadaverine ;
[tex]27.40\%=\frac{z\times 14 g/mol}{102.2 g/mol}\times 100[/tex]
[tex]z=\frac{27.40\times 102.2 g/mol}{100\times 14 g/mol}=2.00\approx 2[/tex]
Molecular formula of Cadaverine :
= [tex]C_xH_yN_z= C_{5}H_{14}N_2[/tex]
C) Epinephrine contains 59.0% C, 7.1% H, 26.2% O, and 7.7% N by mass
Molar mass of Epinephrine = 180 g/mol.
Let the molecular formula of Epinephrine be =[tex]C_xH_yO_zN_w[/tex]
Number of carbon atoms in 1 molecule of Epinephrine ;
[tex]59.0\%=\frac{x\times 12 g/mol}{180 g/mol}\times 100[/tex]
[tex]x=\frac{59.0\times 180 g/mol}{100\times 12 g/mol}=8.85\approx 9[/tex]
Number of hydrogen atoms in 1 molecule of Epinephrine ;
[tex]7.1\%=\frac{y\times 1 g/mol}{180 g/mol}\times 100[/tex]
[tex]y=\frac{7.1\times 180 g/mol}{100\times 1 g/mol}=12.78\approx 13[/tex]
Number of oxygen atoms in 1 molecule of Epinephrine ;
[tex]26.2\%=\frac{z\times 16 g/mol}{180 g/mol}\times 100[/tex]
[tex]z=\frac{26.2\times 180 g/mol}{100\times 16 g/mol}=2.94\approx 3[/tex]
Number of nitrogen atoms in 1 molecule of Epinephrine ;
[tex]7.7\%=\frac{w\times 14 g/mol}{180 g/mol}\times 100[/tex]
[tex]w=\frac{7.7\times 180 g/mol}{100\times 14 g/mol}=0.99\approx 1[/tex]
Molecular formula of Epinephrine :
= [tex]C_xH_yO_zN_w= C_9H_{13}O_3N_1[/tex]
