How would you prepare 1600 mL of a pH=1.50 solution using concentrated ( 12 M) HCl ?

Name: Problem 61, Chapter 13: Chemistry An Atoms First Approach
Uploaded: 2020-02-22T20:51:53-08:00
Duration: 5 min 5 s
Channel: Ian Kaigh
Description: How would you prepare 1600 mL of a pH=1.50 solution using concentrated ( 12 M) HCl ?

How would you prepare 1600 mL of a pH=1.50 solution using...

Key Concepts

pH and Hydrogen Ion Concentration

pH is defined as the negative logarithm of the hydrogen ion concentration, pH = -log[H+]. This relationship is crucial for determining the required [H+] in a solution when a specific pH is targeted. Understanding this concept allows one to convert a desired pH value into a molarity of hydrogen ions, which is essential for subsequent calculations in solution preparation.

Molarity

Molarity is a unit of concentration that describes the number of moles of solute per liter of solution. In the context of preparing acid solutions, knowing the molarity allows one to determine how much of a concentrated acid is needed to achieve a desired concentration upon dilution. This concept is key in calculating the amount of a concentrated reagent required to produce a specific concentration in the final solution.

Dilution Formula

The dilution formula, M1V1 = M2V2, is based on the principle that the number of moles of solute remains constant when a solution is diluted. This equation is used to find the volume of a concentrated solution needed to prepare a solution of a desired concentration and total volume. It ensures that the dilution process is carried out accurately.

Safe Laboratory Procedures

Safe laboratory procedures are critical when handling concentrated acids, as they can be highly corrosive and exothermic. Procedures such as adding acid to water rather than the reverse, wearing appropriate protective gear, and working in a controlled environment like a fume hood help minimize risk and ensure safety during the dilution and preparation of concentrated acid solutions.

Transcript

00:02 This is the answer to chapter 14, problem number 63 from the zoomdahl chemistry textbook.

00:10 This problem asks us, how would you prepare 1 ,600 milliliters of a ph 1 .5 solution using concentrated 12 -molar hydrochloric acid? okay, so what i've done here across the top of the screen, i have written out our three knowns, and then i've written out the two equations that we're going to use to answer this question, answer this problem.

00:36 So we are trying to make a 1 .6 -00 -liter, which is the same as 1 ,600 -millimeter solution.

00:46 It has to be ph 1 .5.

00:48 And we're going to make that using 12 -molar hydrochloric acid.

00:52 So the first thing that we're going to do is to represent 12 -molar hydrochloric.

00:57 Acid as a concentration because that is going to allow us to use the expression m1v1 equals m2 v2, which is an equation relating to volume and concentration.

01:12 And this equation tells us how to make dilutions of a particular solution.

01:18 So 12 molar hcl.

01:23 Okay, no, sorry.

01:24 Okay, so ph equals 1 .50 in our.

01:28 Target solution here.

01:30 So ph equals 1 .50 and so if we use this ph expression, the ph equation, we will then raise 10 to the negative 1 .50 power and that is going to give us 0 .0 .036 as our concentration of hydrogen ions.

02:01 So 0 .0316 molar.

02:05 So that is going to be the concentration of hydrogen ions in our final solution that we were trying to make here.

02:13 Okay.

02:14 And so now we have our m2 and v2.

02:23 Okay.

02:23 So that's going to be our m2 and v2.

02:24 Okay.

02:25 So that's going to be our m2.

02:31 Our v2 is going to be the 1 .6 .00 liter.

02:36 And i changed this from milliliters to liters because you need this to be in liters for this expression to really work well...