Water flowing through pipes of carbon steel must be kept at pH 5 or greater to limit corrosion.

Water flowing through pipes of carbon steel must be kept at...

Key Concepts

Concentration Measurements

Concentration measurements, including units like parts per million (ppm) and percentage concentrations, are used to quantify the amount of a substance present in a mixture. Understanding these units is crucial for accurately assessing the levels of acidic compounds in a system and for calculating the amount of neutralizer required.

Stoichiometric Calculations

Stoichiometric calculations involve determining the quantitative relationships between reactants and products in a chemical reaction. In the context of pH regulation, these calculations help in determining the exact amount of a neutralizing agent, such as a salt, needed to counteract the effects of added acids.

Corrosion Prevention

Corrosion prevention encompasses methods and practices used to protect metals from deteriorating due to reactions with their environment, particularly oxidation. By controlling factors such as pH, which influences the rate of corrosive reactions, industries can extend the life of materials like carbon steel pipes.

Acid-Base Neutralization

Acid-base neutralization is a chemical reaction in which an acid and a base react to form water and a salt, thereby reducing the acidity or basicity of the solution. This concept is fundamental in processes where controlling pH is necessary, such as adjusting the acidity of water to prevent metal corrosion.

pH is a scale used to specify the acidity or basicity of an aqueous solution, measured as the negative logarithm of the hydrogen ion concentration. Maintaining a certain pH level is crucial in many applications, as it influences chemical reactions, biological processes, and material compatibility, such as preventing corrosion in metal pipes.

Buffer Systems

Buffer systems are mixtures of a weak acid and its conjugate base that resist changes in pH when small amounts of acid or base are added. They are essential in maintaining a stable pH environment, which is critical in applications like water treatment for corrosion control in pipelines.

Transcript

00:02 Question number 109 is an extremely challenging question that i'm moderately surprised to see in a general chemistry textbook.

00:12 It takes into account some acid -based chemistry principles, some hydrodynamic principles where we have a flow of water through pipes at so many pounds per hour, and then a whole bunch of different unit conversions.

00:28 We have in the water stream a strong acid, sulfuric acid, at 10 parts per million, and then the weak acid acetic acid at 0 .015%.

00:42 So in addition, we have to, with our unit conversions, convert parts per million and percent by mass acetic acid, into something more manageable like molarity.

00:56 So let's begin.

00:58 We have 10 parts per million sulfuric acid.

01:04 So let's take the 8 .0 times 10 to the 3 pounds of water that pass per hour.

01:14 We won't need to worry about the per hour part because the entire question is in reference to the pounds of sodium acetate that we need to add per hour.

01:26 So we will just take the pounds of the water stream per hour and use that as our reference.

01:33 So if we have 8 .0 times 10 to the 3 pounds of water, we can convert that into grams of water and then go from grams of water to grams of sulfuric acid using the part per million definition.

01:49 If we have 10 parts per million, we have 10 grams of sulfuric acid per million grams of water.

02:00 Then we can convert the grams of sulfuric acid into moles of sulfuric acid.

02:09 And this is where we will begin.

02:11 We then have, in one hour, with 8 ,000 pounds of water passing by with a 10 ppm concentration of sulfuric acid.

02:21 We have 0 .370 moles of sulfuric acid.

02:26 Let's do the same thing with a 0 .015 mass percent acetic acid.

02:32 We'll take our 8 ,000 pounds of water, passing per hour, convert it to grams of water, and then convert the grams of water to grams of acetic acid, using the definition of 0 .015 grams acetic acid per 100 grams of water.

02:50 Then we'll convert the grams of acetic acid into moles of acetic acid.

02:55 And this is how many moles of acetic acid that we would have present in the 8 ,000 pounds of water.

03:02 Okay, what we now want to do is we want to figure out how much of the weak base sodium acetate trihydrate needs to be added in order to maintain the ph at 5 or greater.

03:22 So the first thing that we need to recognize is because h2s .o4 is a strong acid, not just the first hydrogen, but the second hydrogen is pretty strong too.

03:35 It's even stronger than acetic acid.

03:38 That for every, that we will need to add two moles of sodium acetate for every mole of h2s...

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