Question

Heme, obtained from red blood cells, binds oxygen, \(\mathrm{O}_{2}\). How many moles of heme are there in \(150 \mathrm{~mL}\) of \(0.0019 M\) heme solution?

Short answer

\(0.000285\) moles of heme.

Step-by-step solution

Understand the Relationship

To find the number of moles of heme, we need to use the formula for molarity, which is defined by the equation: \( M = \frac{n}{V} \). Here \( M \) is the molarity, \( n \) is the number of moles, and \( V \) is the volume in liters.

Convert Volume to Liters

The volume given is in milliliters, so we need to convert it to liters to use it in the formula. Since there are 1000 mL in a liter, convert \( 150 \, \text{mL} \) to liters: \[ 150 \, \text{mL} = 0.150 \, \text{L} \]

Rearrange Formula to Solve for Moles

We need to rearrange the formula \( M = \frac{n}{V} \) to solve for \( n \). This gives us: \[ n = M \times V \]

Substitute Known Values

Substitute the known values for molarity and volume into the formula: - Molarity \( M = 0.0019 \, \text{M} \)- Volume \( V = 0.150 \, \text{L} \)Thus, \[ n = 0.0019 \, \text{M} \times 0.150 \, \text{L} \]

Perform the Calculation

Calculate the number of moles using the substituted values: \[ n = 0.0019 \times 0.150 = 0.000285 \] moles of heme.

Key concepts

Understanding Moles

In chemistry, the concept of moles is foundational for understanding quantities of substances. The mole is a unit that measures the amount of a substance. It provides a bridge between the atomic scale and the macroscopic scale, allowing us to count atoms, molecules, or ions in a given sample.
- One mole represents approximately \(6.022 \times 10^{23}\) entities, which is Avogadro's number. This massive number represents the quantity of atoms, molecules, or other basic units in a pure substance.
Knowing how many moles are present in a solution helps chemists calculate the concentrations and make accurate predictions about the reactions that might occur.

Volume Conversion Essentials

When dealing with molarity and moles, volume conversion is crucial, especially when volumes are provided in different units. Typically, molarity calculations require the volume to be in liters.
- To convert milliliters to liters, remember that 1000 milliliters equals 1 liter. This implies that any volume in milliliters must be divided by 1000 to convert to liters.
- For instance, 150 mL can be converted to liters by dividing 150 by 1000, resulting in 0.150 L.
This conversion makes it straightforward to use in the molarity formula, which consistently uses liters as the volume unit.

Exploring Solution Chemistry

Solution chemistry focuses on solutions and their components. It covers aspects such as concentration, molarity, and how different substances interact within a solution.
- Molarity, which is defined as moles of solute per liter of solution, is a key concept in solution chemistry. The formula is expressed as \(M = \frac{n}{V}\), where \(n\) is moles and \(V\) is volume in liters.
- Understanding the molarity and concentration of solutions aids in predicting how substances will react.
Chemists rely on solutions to determine how molecules are distributed in a solvent and interact. This understanding is fundamental for applications ranging from medication formulations to industrial chemical processes. Always ensure the volume is in liters and the molarity is accurate to guarantee reliable results.