The typical concentration of Mg 2+ in blood is 3 mEq/L. How many milligrams of Mg 2+ are in 250 mL of blood?

Hello, everyone. Today, we are being given the following problem. A liquid antacid made up of aluminum hydroxide contains 1.54 million equivalent per liter of aluminum. Calculate the mass in milligrams of aluminum present in a 355 millimeter bottle of the antacid. So before we do that, let's make note of one quick thing for ions, one equivalent is going to equal one mole of charge. And so with that, we can begin finding our mass of aluminum. So first, we need to find the gram equivalent of aluminum. And to do that, we are first going to take Aluminums Molar Mass, which states that one mole of aluminum Is equal to 26.98 g. And this is per the periodic table. We're then gonna multiply by the conversion factor that one mole of aluminum has three moles of charge. And that comes from the fact that it has a plus three charge. And then lastly, we're gonna multiply by the conversion factor that one equivalent is equal to one mole of charge. So we're getting rid of our units of our moles of aluminum and the moles of charge To get an answer a gram equivalent of 8.99 g per equivalent. And so we're gonna then use that to find the overall mass of aluminum. And so to begin with this, we're going to take what we were initially given a MB bottle. We're then gonna convert those middle leaders into leaders by using the conversion factor that one middle leader is equal to 10 to the negative third leaders. And then we can use the conversion factor which can be found in the reference text that one leader is equal to 1.54 milli equivalents. And it can also be found in the question stem to then get rid of arm illiquid glint. In terms in choice to switch it to equivalents. We're gonna use the conversion factor that one milli equivalent is equal to 10 to the negative third equivalents. Then we're going to see that in one equivalent, we have 8.99 g of that aluminum. And then lastly because our answer has to be in terms of milligrams, we're gonna use the conversion factor that one mg is equal to 10 to the negative third grams of aluminum. And so our units of middle leaders leaders mil equivalence equivalence is and grams of aluminum cancel out to give us a final answer of 4.92 milligrams of aluminum. And with that, we have answered the question overall, I hope this helped ahead until next time.

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9. Solutions

Equivalents

GOB Chemistry

9. Solutions

Equivalents

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Problem 19

Textbook Question

The typical concentration of Mg²⁺ in blood is 3 mEq/L. How many milligrams of Mg²⁺ are in 250 mL of blood?

Verified step by step guidance

Step 1: Understand the given information. The concentration of Mg²⁺ is provided as 3 mEq/L (milliequivalents per liter), and the volume of blood is 250 mL. The goal is to determine the mass of Mg²⁺ in milligrams.

Step 2: Convert the volume of blood from milliliters to liters, since the concentration is given in mEq/L. Use the conversion factor: 1 L = 1000 mL. The formula is: \( \text{Volume in liters} = \frac{\text{Volume in mL}}{1000} \).

Step 3: Calculate the total milliequivalents of Mg²⁺ in the given volume of blood. Use the formula: \( \text{Total mEq} = \text{Concentration (mEq/L)} \times \text{Volume (L)} \).

Step 4: Convert milliequivalents (mEq) to millimoles (mmol). For Mg²⁺, 1 mEq corresponds to 0.5 mmol because the charge of Mg²⁺ is +2. Use the formula: \( \text{mmol} = \text{mEq} \times 0.5 \).

Step 5: Convert millimoles to milligrams. The molar mass of Mg²⁺ is approximately 24.31 g/mol. Use the formula: \( \text{Mass in mg} = \text{mmol} \times \text{Molar mass (mg/mmol)} \), where \( \text{Molar mass (mg/mmol)} = 24.31 \).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Milliequivalents (mEq)

Milliequivalents (mEq) is a unit of measurement used to express the concentration of ions in a solution. It accounts for the charge of the ion, allowing for a standardized way to compare different ions. For magnesium (Mg²⁺), 1 mEq corresponds to 1 millimole of the ion, considering its valence of +2. Understanding mEq is crucial for converting between different units of concentration.

Concentration Calculation

Concentration calculation involves determining the amount of a substance in a given volume of solution. In this case, the concentration of Mg²⁺ is given as 3 mEq/L, which means there are 3 milliequivalents of magnesium in one liter of blood. To find the total amount in 250 mL, one must convert the volume from liters to milliliters and apply the concentration to find the total mEq present.

Conversion from mEq to mg

To convert milliequivalents (mEq) of an ion to milligrams (mg), one must use the molecular weight of the ion. For magnesium, the atomic weight is approximately 24.3 g/mol. The conversion formula is: mg = mEq × (molecular weight / valence). This step is essential for translating the concentration of Mg²⁺ in mEq to its mass in mg, which is necessary for the final answer.

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