Question

What does it mean when we say that the concentration of \(\mathrm{Ca}^{2+}\) in blood is \(3.0 \mathrm{mEq} / \mathrm{L} ?\)

Short answer

3.0 mEq/L means 3.0 milliequivalents of calcium ions per liter of blood.

Step-by-step solution

Understanding mEq

The term 'mEq' stands for milliequivalents, which is a unit of measure used to express the concentration of electrolytes in a solution. It specifically considers both the mass of the ions and their charge.

Determine Equivalent Weight of Calcium Ion

Calcium ions (\(\mathrm{Ca}^{2+}\)) carry a charge of +2. The equivalent weight of an ion is calculated by dividing its atomic weight by its valence (charge). The atomic weight of calcium is about 40 grams/mole.

Calculate Equivalent Weight

The equivalent weight of \(\mathrm{Ca}^{2+}\) is calculated as: \[\text{Equivalent weight} = \frac{\text{Atomic weight}}{\text{Charge}} = \frac{40}{2} = 20 \, \text{g/equiv}\].

Convert to Milliequivalents

Since 1 equivalent is 1000 milliequivalents (mEq), a concentration of 3.0 mEq/L means there are 3.0 milliequivalents of calcium ions per liter of blood.

Interpretation of Concentration

The concentration of \(\mathrm{Ca}^{2+}\) in blood being 3.0 mEq/L indicates that for every liter of blood, there are 3.0 milliequivalents of calcium ions, reflecting both the quantity and charge of the ions present.

Key concepts

Milliequivalents

Milliequivalents, abbreviated as mEq, are units used to measure the concentration of electrolytes in solutions. This measurement is essential in understanding the presence and significance of ions in various liquids like blood.

Unlike regular concentration measures such as moles or grams, milliequivalents specifically consider the charge of the ions, along with their mass. For example, in blood chemistry, knowing the mEq of ions like calcium can give insights into both the number and type of these ions.

This understanding becomes crucial for bodily functions where ion balance is pivotal, such as in nerve function and muscle contraction. By utilizing mil-equivalents, medical professionals and chemists can precisely manage and adjust electrolytic balances, vital for maintaining homeostasis.

Calcium Ion

Calcium ions, denoted as \(\mathrm{Ca}^{2+}\), are vital electrolytes in biological systems. These ions carry a positive charge of +2 due to the loss of two electrons.

In the body, calcium ions play crucial roles, including:

• Supporting bone and dental health
• Regulating muscle contractions and nerve functions
• Assisting in blood clotting processes

Understanding the concentration of \(\mathrm{Ca}^{2+}\) ions in solutions like blood, as denoted in milliequivalents per liter (mEq/L), is vital for diagnosing and treating various health conditions.

A concentration measurement of 3.0 mEq/L in blood indicates a balance critical for normal physiological functions, demonstrating their significant role in maintaining health.

Equivalent Weight

Equivalent weight is an essential concept in chemistry used to relate the amount of a substance to its reactive capacity. For ions, it is calculated by dividing the atomic weight of the ion by its valency.

Let's consider calcium ions \(\mathrm{Ca}^{2+}\). The atomic weight of calcium is approximately 40 grams per mole. To find the equivalent weight, this atomic weight is divided by the valency, which is the charge of the ion (for calcium, \(+2\)).
The formula is:\[\text{Equivalent weight of } \mathrm{Ca}^{2+} = \frac{\text{Atomic weight}}{\text{Charge}} = \frac{40}{2} = 20 \, \text{g/equiv}\]
This means 20 grams of calcium ions is equivalent to one equivalent of \(\mathrm{Ca}^{2+}\). In practical applications, such as medical or biochemical settings, this information aids in calculating the molarity and other concentration measures necessary for accurate analysis and formulations.