Final answer:
To mix a transcription reaction to a final volume of 20 ml, individual component volumes must be calculated according to desired final concentrations. Specific concentrations are required to provide precise volumes for the reaction. For concentrations over time, reaction rates or half-lives are needed to determine the remaining concentration.
Step-by-step explanation:
To calculate now to mix a transcription reaction for a final volume of 20 ml, one would need to know the desired final concentrations of all components in the reaction mixture, such as nucleotides, buffer, enzymes, and template DNA. Once these concentrations are known, one can calculate the volume of each component needed. For example, if the final concentration of an enzyme needed is 1 U/ml in a 20 ml reaction, you would add 20 U of the enzyme. However, the question seems to lack specific details about the concentrations of the components required.
If we consider a scenario related to the concentration remainining after 20 min such as in the case of an initial concentration of butadiene being 0.0200 M, this pertains to reaction kinetics and woud require information about the rate of the reaction or the half-life of the reactant to provide an accurate answer.