"You're creating a standard curve for pyruvate. You need to create a standard with 20 micromoles in a cuvette. How much 100 mM pyruvate would you need?"

My understanding is to solve for VOLUME using the equation:

micromoles = (mM)(volume in ml)

20 micromoles = (100mM)(x)
Solve for x

x = 0.2mL

Am I on the right track?

Yes, you are on the right track. To calculate the volume of the 100 mM pyruvate solution needed to obtain 20 micromoles, you can rearrange the equation:

micromoles = (mM)(volume in ml)

Plugging in the given values:

20 micromoles = (100 mM)(x ml)

To solve for x (the volume in ml), divide both sides of the equation by 100 mM:

x ml = (20 micromoles) / (100 mM)

Now, you need to convert micromoles to moles and milliliters to liters so that the units match:

20 micromoles = 20 x 10^-6 moles
x ml = (20 x 10^-6 moles) / (100 x 10^-3 moles/liter)

Simplifying:

x ml = 0.2 ml

So, you would need 0.2 ml of the 100 mM pyruvate solution to obtain 20 micromoles.