# Glucose + 2X -enzymes-> 2 Pyruvic acid + 4ATP. What substances is indicated by "X" in this equation?

Feb 9, 2017

See explanation.

#### Explanation:

$\text{Glucose" + 2"X" - "enzymes" -> 2 "Pyruvic acid" + 4"ATP}$

Let us represent the chemical reaction

${C}_{6} {H}_{12} {O}_{6} + 2 X \to 2 {C}_{3} {H}_{4} {O}_{3} + 4 {C}_{10} {H}_{16} {N}_{5} {O}_{13} {P}_{3}$

Now multiply the number of moles to the number of moles of each element

for example = $2 {H}_{2} = H 2 \cdot 2 = H 4$

This is not true but helps in determining the missing reactant or missing product as in this problem.

The result would be

${C}_{6} {H}_{12} {O}_{6} + 2 X \to {C}_{6} {H}_{8} {O}_{6} + {C}_{40} {H}_{56} {N}_{20} {O}_{52} {P}_{12}$

Now show the number of atoms of each element in each compound we know.

${C}_{6} {H}_{12} {O}_{6} = {H}_{12} , {O}_{6} , {C}_{6}$
${C}_{6} {H}_{8} {O}_{6} = {H}_{8} , {O}_{6} , {C}_{6}$
${C}_{40} {H}_{56} {N}_{20} {O}_{52} {P}_{12} = {H}_{56} , {O}_{52} , {C}_{40} , {P}_{12}$

Add the no. of elements in the products and subtract it from the elements in reactants. it will give

${H}_{56} + {H}_{8} - {H}_{12} = \text{52 atoms of hydrogen}$

${O}_{52} + {O}_{6} - {O}_{6} = \text{52 atoms of oxygen}$

${C}_{40} + {C}_{6} - {C}_{6} = \text{40 atoms of carbon}$

${P}_{12} - 0 = {P}_{12}$

so the remaining atoms would be $2 \text{X}$ as energy is neither created nor destroyed, so

$\text{X" = (C_40H_52O_52P_12)/2 = C_20H_26O_26P_6}$