1. Larry\'s doctor orders an esophageal pH test in which the amount of acid ente

Question

1. Larry's doctor orders an esophageal pH test in which the amount of acid entering the esophagus from the stomach is measured over 24 h. A probe that measures the pH is inserted into the lower esophagus above the esophageal sphincter. The pH measurements indicate a reflux episode each time the pH drops to 4 or less. In the 24-h period, Larry has several reflux episodes and his doctor determines that he has chronic GERD. He and Larry discuss treatment for GERD, which includes eating smaller meals, not lying down for 3 h after eating, making dietary changes, and losing weight. Antacids may be used to neutralize the acid coming up from the stomach. Other medications known as proton pump inhibitors (PPIs), such as Prilosec and Nexium, may be used to suppress the production of HCl in the stomach (gastric parietal cells), which raises the pH in the stomach to between 4 and 5, and gives the esophagus time to heal. Nexium may be given in oral doses of 40 mg once a day for 4 weeks. In severe GERD cases, an artificial valve may be created at the top of the stomach to strengthen the lower esophageal sphincter. After Larry had taken Nexium for 4 weeks, the pH in his stomach was raised to 4.47.

What is the [H3O+] in his stomach? Express the concentration to two significant figures and include the appropriate units. [H3O+] =

Explanation / Answer

1.)

Finding [H3O+]

Given pH = 4.47

formula to find [H3O+] = 10-pH

[H3O+] = 10-4.47

[H3O+] = 3.39 x 10-5 M

Writing answer in two significant figures

[H3O+] = 3.4 x 10-5 M

2) Part A

Arrhenius acid: the species which increase H+ ions in aqueous soluiton

H3PO3, HI, HCl,

Arrhenius base: the substance which give OH- ions in aqueous solution

Hg(OH)2, Zn(OH)2, Ba(OH)2 , NaOH

Neither:

KNO3, CH4

Part B

Brønsted-Lowry acid: The species which gives protons -H+ ions

H2SO4, HI, H3PO4

Brønsted-Lowry base: The species which accepts protons

(CH3)3N, NH3, C2H5NH2

Neither:

KBr, CHCl3

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.