What is the molarity of an HNO 3 solution if 68.5 mL is needed to react with 25.0 mL of 0.150 M

What is the molarity of an HNO 3 solution if 68.5 mL is...

Key Concepts

Titration

Titration is an analytical technique used to determine the concentration of an unknown solution by gradually adding a solution of known concentration until the reaction reaches its equivalence point. This process relies on the stoichiometric relationships in the balanced reaction to accurately compute the unknown concentration.

Unit Conversion

Unit conversion is crucial in chemical calculations to ensure that all measurements are expressed in compatible units. For example, converting milliliters to liters is necessary when using the molarity formula, which requires volume to be in liters.

Molarity

Molarity is a concentration measurement defined as the number of moles of solute per liter of solution. It is fundamental in quantitative chemical analysis for determining how much of a substance is present in a given volume of solution.

Stoichiometry

Stoichiometry involves the quantitative relationships between reactants and products in a balanced chemical equation. It allows the determination of the moles of one reactant required to completely react with a given amount of another, ensuring that the proportions defined by the chemical equation are maintained.

Transcript

00:01 In this problem, we are given the following information about an acid in the base, and our goal is to calculate the molarity of the nitric acid.

00:13 Since we're working with units of molarity, remember that molarity abbreviated with an n is equal to the number of moles divided by the volume in liters.

00:26 So this is moles and liters.

00:29 It will help for the purposes of really getting at why we're doing all these different operations to realize that we can write this relationship in three different ways, as the molarity definition, as solving for the number of moles.

00:48 So the number of moles is equal to the molarity times the volume, or solving for the volume as equal to the number of moles divided by the molarity.

00:58 Okay, so be able to interconvert between these readily so that we can see that in our, in the process we're going to follow, we're going to start with the substance that we know the most about.

01:12 That's potassium hydroxide.

01:14 We have, as you can see, two of the three variables.

01:19 So i can solve to the third.

01:21 Typically, it's going to be number of moles.

01:24 So our first step is find moles.

01:29 Potassium hydroxide because that is the substance that i know the most about.

01:34 Once i have that, i'm going to use the mole -to -mull ratio to convert that to moles, essentially to find moles of nitric acid.

01:54 So that'll give me more information about this substance.

01:57 And once i have more information about the nitric acid, i will be able to finish and calculate the molarity of nitric acid.

02:12 Let's start with step one.

02:16 Since we're working with molarity, we need to work with milliliters.

02:20 I'm going to have to find moles.

02:21 We're going to multiply the molarity, which is 0 .150 moles for every one liter.

02:29 That's the definition of molarity.

02:31 We're going to multiply that times the volume in liters.

02:35 So instead of 25 .0 militers, i'm going to write 0 .0 .0 .0 liters.

02:41 And that is equal to 0 .00375.

02:50 What are my units? remember that my leaders cancel and the goal is to find moles.

02:54 So the units are moles of k -o -h.

03:02 That is step one.

03:07 Next, i'm going to use the mole -to -mole ratio to relate the base to the acid.

03:13 This one's pretty straightforward.

03:16 For every one mole of k -o -h, i have one mole of nitric acids.

03:21 So the two are equal.

03:23 So i don't even have to do any math, really...

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