Wednesday, January 10, 2018

Gutful of Gas

People can eat interesting things.
In the 1960s in Australia, Leon Samson was eating razor blades to amuse audiences, he even started to eat, slowly, in bits, a car for a bet. A little later, France produced Michel Lotito who was also eating odd things to entertain us, including an airplane between 1978 and 1980.

A razor blade is made out of steel, a particular kind of steel known as razor blade steel. A 2.61 gram razor blade contains between about 13% chromium, 0.6% carbon, and  the rest is iron. Samson would chew up a razor blade and swallow it.

After leaving the mouth, the chewed-up bits of razor blade travel to the stomach. An empty stomach has a volume of about 75 mL but when we eat the volume of the stomach can expand out to about 1 L. Protein-digesting enzymes known as proteases are released into the stomach to help begin the break up of the proteins like you find in meat, fish, eggs and cheese. The optimum pH for these proteases is at about pH 2, so hydrochloric acid is also released into the stomach.

So the small bits of razor blade now find themselves surrounded by hydrochloric acid. Hydrochloric reacts with metals, like the iron in steel, to produce hydrogen gas. Now gases have an interesting property, they expand out to fill the available space. This suggests that eating razor blades might result in a feeling of being bloated. Thankfully, it appears that it takes about 24 hours for the complete reaction between a razor blade and hydrochloric acid in the stomach, plenty of time to remove the gas build-up via burping or, um, farting.

Hydrogen gas is commonly found in our intestines, along with other gases like carbon dioxide, oxygen and nitrogen. Some of these gases get there when we swallow air along with our food and drink, but they also come from chemical reactions inside our bodies. If our bodies are healthy and working well, all the usual gases will be present in the usual concentration, but if there is something wrong, if we are sick, the nature and composition of the gases will change.

Researchers at RMIT University in Melbourne, Australia, have developed and trialed an "ingestible electronic capsule" which is capable of sensing and measuring the gases in the gut like hydrogen, carbon dioxide and oxygen. These capsules offer a new, non-invasive way to monitor the health of our gut. The capsules can be collected after they have been excreted (apparently painlessly).

Kourosh Kalantar-Zadeh, Kyle J. Berean, Nam Ha, Adam F. Chrimes, Kai Xu, Danilla Grando, Jian Zhen Ou, Naresh Pillai, Jos L. Campbell, Robert Brkljańća, Kirstin M. Taylor, Rebecca E. Burgell, Chu K. Yao, Stephanie A. Ward, Chris S. McSweeney, Jane G. Muir, Peter R. Gibson. A human pilot trial of ingestible electronic capsules capable of sensing different gases in the gut. Nature Electronics, 2018; 1 (1): 79 DOI: 10.1038/s41928-017-0004-x

Suggested Further Reading 
Experimental Design:
Name and Formula of Binary Covalent Compounds:
Percentage Composition:
Mass-moles Calculations:
Molar Gas Volume Calculations:
Ideal Gas Law Calculations:
Metal + Non-Oxidising Acid Reaction:
Hydrogen Ion Concentration of Strong Acids: 
Reaction Calculations: Mass and Moles 

Suggested Study Questions
  1.   Design an experiment to determine how long it would take for a razor blade to react completely with the hydrochloric acid in the stomach. Investigate ways to speed up, or, to slow down, this reaction.
  2. Give the formula for each of the following:
    • hydrogen gas
    • nitrogen gas
    • oxygen gas
    • carbon dioxide gas
    • hydrochloric acid
  3.   Determine the percentage composition of each of the following compounds
    • hydrogen chloride gas
    • carbon dioxide gas
  4. From the information in the article, calculate the mass of each of the following elements found in a razor blade:
    • iron
    • chromium
    • carbon
  5. Using the information above, calculate the moles of each of the following elements found in a razor blade:
    • iron
    • chromium
    • carbon
  6. Calculate the moles of hydrogen gas that occupy the entire volume of a "full" stomach under the following conditions:
    • 0oC and 100 kPa
    • 25oC and 100 kPa
    • 37oC and 100 kPa
  7. Write a balanced chemical equation for the reaction between the hydrochloric acid in the stomach and the iron in a razor blade.
  8. Calculate the concentration of acid released into the stomach using the information in the article. 
  9. Use the balanced chemical equation to determine the volume of hydrogen gas produced when all the iron in a razor blade has reacted with hydrochloric acid.
  10. Consider all the information in the article, and the calculations you have performed so far. Explain why it takes 24 hours for a razor blade to be completely digested in the stomach.

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