Chemistry (including Biochemistry)/Solubility of gases

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Question
Why do the solubility of gases, strong acids and bases, and chemicals such as NaSO4and CaSO4, decrease as the temperature increases?

Thank you~:)

Answer
Hello Gen!

In water, the solubility of gases decreases as the temperature increases. (In organic nonpolar solvents it is the opposite; check out the chemwiki article from UC Davis for more on that.)

This alteration in solubility is related to the second law of thermodynamics: in this case, we're talking about the total energy of the system affecting its entropy. Water that has a lot of O2, N2, or CO2 in it is a polar solution that has nonpolar gases knocking about inside. Try to imagine pure water as a series of vibrating, bent molecules tumbling over one another, like a flattish letter V. The two ends of the V are somewhat positively charged, and the middle is somewhat negatively charged. Neither charged bit of the V 'likes' rubbing up against the pill-shaped gas molecules. The waters want to play only with other waters, so they try and push the gases away from themselves, which ends up being together with other gases in clumps.

Clumped gases result in a solution that is highly ordered. Highly ordered solutions means less entropy in the system. Less entropy is not a favored state, and any inputs of energy would go directly to increasing the entropy in the system.

In a solution that is cold, the water molecules tumble much more slowly. This means that they cannot 'reject' the gas molecules as efficiently, because the waters are lazy and sluggish. So more gas can stay within the water because the water is too 'lazy' to kick it out. The heat energy of the system is not enough to overcome the entropy of waters not liking rubbing up against gases.

In a warm solution, water molecules tumble quickly. Because of this, they can organize themselves very well, and push all the gas molecules together and ultimately bubble out of the solution. The heat energy of the system facilitates rapid water movement and expulsion of gas.

Polar ions such as strong acids and basis, or salts, associate well with charged water molecules. A drop in solubility with increasing temperature may have more to do with the boiling point of water making the water leave the solution. :)

Does this make sense? Feel free to follow up if I can be more help. Apologies this is late.

Articles I referenced that may help comprehension:
http://en.wikipedia.org/wiki/Water
http://chemwiki.ucdavis.edu/Physical_Chemistry/Physical_Properties_of_Matter/Sol

Chemistry (including Biochemistry)

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Trista Robichaud, PhD

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No homework questions, especially ones copied and pasted from textbooks. I will answer questions about principles or give hints, but I do not do other's homework. I'm comfortable answering basic biochemistry, chemistry, and biology questions up to and including an undergraduate level of understanding. This includes molecular biology, protein purification, and genetics. My training/inclination is primarily in structural biology, or how the shapes of things affect their function. Other interests include protein design, protein engineering, enzyme kinetics, and metabolic diseases such as cancer, atherosclerosis, and diabetes. My chemistry weaknesses are that I do not know organic or inorganic synthesis well, nor am I familiar with advanced inorganic reactions. I will attempt quantum mechanics and thermodynamics questions, but primarily as they relate to biological systems. Furthermore, I cannot tell you if a skin photograph is cancerous, or otherwise diagnose any disease. I can tell you how we currently understand the basic science behind a disease state, but I cannot recommend treatment in any way. Please direct such questions to your medical professional.

Experience

I hold a PhD in Biomedical Science from the University of Massachusetts Medical School in Worcester. I specialize in Biochemistry, with a focus on protein chemistry. My thesis work involved the structure and functions of the human glucose transporter 1. (hGLUT1) Currently I am a postdoc working in peptide (mini-protein) design and enzymology at the University of Texas Health Science Center in San Antonio, Texas. I am in Bjorn Steffensen's lab (PhD, DDS), studying gelatinase A and oral carcinoma.

Organizations
2001 American Association for the Advancement of Science
2007 American Chemical Society
2007 Protein Society
2011 UTHSCSA Women’s Faculty Association


Publications
Levine KB, Robichaud TK, Hamill S, Sultzman LA, Carruthers A. Properties of the human erythrocyte glucose transport protein are determined by cellular context. Biochemistry 44(15):5606-16, 2005. (PMID 15823019)
Robichaud TK, Appleyard AN, Herbert RB, Henderson PJ, Carruthers A “Determinants of ligand binding affinity and cooperativity at the GLUT1 endofacial site” Biochemistry 50(15):3137-48, 2011. (PMID 21384913)
Xu X, Mikhailova M, Chen Z, Pal S, Robichaud TK, Lafer EM, Baber S, Steffensen B. “Peptide from the C-terminal domain of tissue inhibitor of matrix metalloproteinases-2 (TIMP-2) inhibits membrane activation of matrix metalloproteinase-2 (MMP-2)” Matrix Biol. 2011 Sep;30(7-8):404-12. (PMID: 21839835)
Robichaud TK, Steffensen B, Fields GB. Exosite interactions impact matrix metalloproteinase collagen specificities. J Biol Chem. 2011 Oct 28;286(43):37535-42 (PMID: 21896477)

Poster Abstracts:
Robichaud TK, Carruthers. A "Mutagenesis of the Human type 1 glucose transporter exit site: A functional study." ACS 234th Meeting, Boston MA. Division of Biological Chemistry, 2007
Robichaud TK, Bhowmick M, Tokmina-Roszyk D, Fields GB “Synthesis and Analysis of MT1-MMP Peptide Inhibitors” Biological Chemistry Division of the Protein Society Meeting, San Diego CA 2010
Robichaud TK; Tokmina-Roszyk D; Steffensen B and Fields GB “Catalytic Domain Exosites Contribute to Determining Matrix Metalloproteinase Triple Helical Collagen Specificities” Dental Science Symposium. UTHSCSA 2011
Robichaud TK; Tokmina-Roszyk D; Steffensen B and Fields GB “Exosite Interactions Determine Matrix Metalloproteinase Specificities” Gordon Research Conference on Matrix Metalloproteinase Biology, Bristol RI 2011


Education/Credentials
Oakland University, Auburn Hills MI BS, Biochemistry 1998
University of Massachusetts Medical School, Worcester MA PhD, Biochemistry & Molecular Pharmacology 2001-2008
University of Texas Health Science Center, San Antonio TX Postdoc, Biochemistry 2009-Present


Awards and Honors
1998 Honors College Graduate, Oakland University
2009 Institutional National Research Service Award, Pathobiology of Occlusive Vascular Disease T32 HL07446
2011 1st Place, Best Postdoctoral Poster, Dental Science Symposium, UTHSCSA, April 2011


Past/Present Clients
Invited Seminars:
Robichaud TK, Fields GB. “Synthesis and Analysis of MTI-MMP Triple Helical Peptide Inhibitors” Pathology Research Conference, University of Texas Health Science Center San Antonio Pathology Department (June 18th, 2010)
Robichaud TK & Hill, B “How To Give A Great Scientific Talk” Invited Lecture, Pathobiology of Occlusive Vascular Disease Seminars, UTHSCSA (Nov 11th 2010), Cardiology Seminar Series, Texas Research Park (Feb 21st, 2011)
Robichaud TK; Tokmina-Roszyk D; Steffensen B and Fields GB “Exosite Interactions Determine Matrix Metalloproteinase Specificities” Gordon-Keenan Research Seminar “Everything You Wanted to Know About Matrix Metalloproteinases But Were Afraid to Ask” Bristol, RI (Aug 6th, 2011)

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