How many mEq of Ca^2+ are represented in a 500-mg tablet of calcium gluconate ( molecular weight

How many mEq of Ca^2+ are represented in a 500-mg tablet of...

Key Concepts

Stoichiometric Conversions

Stoichiometry involves using the known relationships between the amounts of substances in a chemical compound or reaction. It allows one to determine how many moles of a particular ion or element are present in a compound by using the compound’s formula and the moles derived from its mass.

Equivalents and Milliequivalents

An equivalent is a measure that takes into account the reactive capacity of a substance, typically considering its ion charge. For ions, one mole of an ion with a charge of +2 corresponds to two equivalents. A milliequivalent is one-thousandth of an equivalent. This conversion is widely used in clinical and chemical settings to express concentrations and dosages, especially when the ionic charge plays a crucial role in the substance’s reactivity.

Molecular Weight

The molecular weight (or molar mass) of a substance is the mass of one mole of its molecules. It provides a conversion factor that allows you to translate a given mass (for example, in milligrams or grams) into the corresponding number of moles, which is the basis for further stoichiometric calculations in chemistry.

Transcript

00:01 In this problem, we're considering a 50 mil aliquot of a solution that contains a solution of edta.

00:09 This solution contains 0 .45 grams of magnesium sulfate in 500 liters of water.

00:17 It required 37 .5 milliliters of edta for titration.

00:22 We're asked to find how many milligrams of calcium carbonate will react with one millimeter of this solution.

00:28 So our first order of business will be to find the molarity of the edta and then find out how many milligrams will be required or how many milliliters could be titrated with one millimeter of that solution.

00:47 Okay.

00:49 So let's figure out what we've got here.

00:57 We have, okay, we've got our moles of magnesium sulfate.

01:09 We have 0 .45 grams, and we were told we had one, what was it, 120 .37 grams per mole.

01:25 That'll give me 0 .30303, 37 around later.

01:38 Okay, and then that's how many moles.

01:51 So i've got 0 .0037 -385 moles.

01:59 In half a liter and then i have a 50 mil aliquot and that'll give me 0 .000 37385 moles of magnesium sulfate so i've got moles of eda equals our moles of magnesium sulfate or magnesium i'm going to worry about i'm going to make a note also calcium moles for reference later.

02:57 Therefore, i will have the malaria of the edta.

03:06 0 .000 -3735 moles divided by 0 .035 liters.

03:25 And that equals, i want to make sure i copied that down.

03:36 376...

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