Final answer:
The potassium ion molarity of 750 ml of blood plasma containing 40 mmol K+ is 0.0533 M after converting milliliters to liters and applying the molarity formula.
Step-by-step explanation:
To calculate the potassium ion molarity of 750 ml of blood plasma containing 40 mmol of K+, you first need to convert the volume from milliliters to liters since molarity is expressed as moles per liter.
In this case, 750 ml is equivalent to 0.750 L. Molarity (M) is defined as the number of moles of solute divided by the volume of solution in liters. Therefore, molarity can be calculated using the formula:
M = moles of solute / liters of solution
Given that there are 40 mmol (which is equal to 0.040 moles, since 1 mmol is 1/1000 of a mole) of potassium ions in the blood plasma, the molarity of potassium ions is:
M = 0.040 moles / 0.750 liters = 0.0533 M