Calculate the percentage of each element in acetic acid, hc2h3o2, and glucose, c6h12o6.b. these two substances have the same empirical formula. what would you expect the percentage composition of the empirical formula to b

1) The percent by mass is calculated by atomic mass of element multiply by number of that element in molecule divided by molecular mass of molecule.

Mr(HC₂H₃O₂) = 4 · Ar(H) + 2· Ar(C) + 2 · Ar(O).  

Mr(HC₂H₃O₂) = 4 · 1 + 2 · 12 + 2 · 16.  

M(HC₂H₃O₂) = 60; relative moecular mass of acetic acid.

Ar(H) = 1; the relative atomic mass of hydrogen atom.  

Ar(C) = 12; the relative atomic mass of carbon atom.  

Ar(O) = 16; the relative atomic mass of oxygen atom.  

ω(H)= 4 · Ar(H) ÷ Mr(HC₂H₃O₂) · 100%.  

ω(H) = (4 · 1 ÷ 60) · 100%.  

ω(H) = 6.67 %; the percentage of hydrogen in acetic acid.

ω(C)= 2 · Ar(C) ÷ Mr(HC₂H₃O₂) · 100%.  

ω(C) = (2 · 12 ÷ 60) · 100%.  

ω(C) = 40%; the percentage of carbon in acetic acid.

ω(O)= 2 · Ar(O) ÷ Mr(HC₂H₃O₂) · 100%.  

ω(O) = (2 · 16 ÷ 60) · 100%.  

ω(O) = 53.33%; the percentage of oxygen in acetic acid.

2) Mr(C₆H₁₂O₆) = 12 · Ar(H) + 6 · Ar(C) + 6 · Ar(O).  

Mr(C₆H₁₂O₆) = 12 · 1 + 6 · 12 + 6 · 16.  

M(C₆H₁₂O₆) = 180; relative moecular mass of glucose.

ω(H)= 12 · Ar(H) ÷ Mr(C₆H₁₂O₆) · 100%.  

ω(H) = (12 · 1 ÷ 180) · 100%.  

ω(H) = 6.67 %; the percentage of hydrogen in glucose.

ω(C)= 6 · Ar(C) ÷ Mr(C₆H₁₂O₆) · 100%.  

ω(C) = (6 · 12 ÷ 180) · 100%.  

ω(C) = 40%; the percentage of carbon in glucose.

ω(O)= 6 · Ar(O) ÷ Mr(C₆H₁₂O₆) · 100%.  

ω(O) = (6 · 16 ÷ 60) · 100%.  

ω(O) = 53.33%; the percentage of oxygen in glucose.

The percentages of each element composing acetic acid and glucose will the same.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e