# Calculate the molar concentration of substrate

• Thrax
In summary, the conversation is about creating a Michealis/Menten curve and finding the X values for the graph. The instructions given are to plot the molar concentration of substrate used in each well by multiplying the volume of substrate added by its concentration (1 mg/ml or 1 ug/ul). The formula weight of the substrate is given as 275 g/mole and it is diluted in 100uL in each well. The calculated molar concentration of substrate in each well is the X value needed for plotting the kinetics curve. One data set of 10uL of substrate is used to calculate the moles, first by converting the volume to mass, then mass to moles, and finally moles to concentration. The
Thrax

## Homework Statement

Hello,
I'm creating a Michealis/Menten curve and need to find the X values for the graph.

## Homework Equations

These are the instructions given to find the X values:

To obtain the X value, plot the molar concentration (molarity) of substrate used in each well.

You can determine this by multiplying the volume of substrate added to each well by the concentration of the substrate (1 mg/ml or 1 ug/ul) to give you a mass.

Paranitrophenylphosphate (the substrate) has a formula weight of 275 g/mole.

The substrate is diluted in 100uL in each well.

Using these values, calculate the molar concentration of substrate in each well across the plate. These are the X values. You are now ready to plot the kinetics curve.

## The Attempt at a Solution

Using one data set of for 10uL of substrate i calculated moles
First converted the 10uL to .010mL

.010mL * 1 mg/ml = .010mg mass of substrate

Converted the .010mg to grams and solved for moles

1.000 x10-5g (1mol / 279g) = 3.58 x10e-8 moles

converted the 100ul to liters

100e-6uL = 1.000e-4 L

then found found moles\liters

3.58 x10e-8 moles / 1.000e-4 L = 3.580e-4 M

Not sure if this is correct or not. I also tried taking the 10ug / 100ul = .100 ug/uL and doing something with that, but got totally lost...

I have just skimmed not checking numbers, but it looks to me like you are following the right path - volume to mass, mass to moles, moles to concentration.

--

Thanks for taking a look!

## 1. How do you calculate the molar concentration of a substrate?

To calculate the molar concentration of a substrate, you need to know the mass of the substrate in grams, the volume of the solution in liters, and the molar mass of the substrate. You can then use the formula: molar concentration = (mass of substrate / molar mass of substrate) / volume of solution.

## 2. Why is it important to know the molar concentration of a substrate?

The molar concentration of a substrate is important because it tells us the amount of substance present in a given volume of solution. This information is crucial in determining reaction rates and identifying optimal conditions for enzymatic reactions.

## 3. What units are used to express molar concentration?

The units used to express molar concentration are moles per liter (mol/L) or molarity (M). Both units represent the number of moles of a substance dissolved in one liter of solution.

## 4. Can the molar concentration of a substrate change over time?

Yes, the molar concentration of a substrate can change over time as the reaction proceeds and the substrate is consumed. This is known as the reaction's progress and can be monitored by measuring the change in substrate concentration at different time intervals.

## 5. How does temperature affect the molar concentration of a substrate?

Temperature can affect the molar concentration of a substrate by altering the rate of the reaction. Generally, an increase in temperature will result in a higher reaction rate, leading to a decrease in substrate concentration over time. However, extremely high temperatures can also denature enzymes and decrease reaction rates.

Replies
10
Views
3K
Replies
4
Views
3K
Replies
4
Views
3K
Replies
4
Views
3K
Replies
1
Views
7K
Replies
19
Views
4K
Replies
10
Views
5K
Replies
4
Views
2K
Replies
2
Views
7K
Replies
1
Views
4K