Your Questions About Hydrogen Bonding

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Water has high bpt because:-
1. Hydrogen bonds are extra forces over and above Van der Waals
2. These extra forces have to be overcome inorder for water to boil

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In steam, hydrogen bonding doesn’t really affect much, since it’s a gas and everything is just flying around everywhere.

In water, the hydrogen bonding gives water a really strong bond between the particles, which makes water have a really high specific heat capacity.

In ice, the hydrogen bonds fit and interlock, which provides an uber hardness to the ice but also increases the volume (compared to water) since the hydrogen bonds are stiff and they take up more space. Imagine people in a crowded bus with all their elbows sticking out (in ice) as compared to a people on a dance floor with their elbows sticking out – they’ll move around so more people could fit in (as in water).

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In these macromolecules, bonding between parts of the same macromolecule cause it to fold into a specific shape, which helps determine the molecule’s physiological or biochemical role. The double helical structure of DNA, for example, is due largely to hydrogen bonding between the base pairs, which link one complementary strand to the other and enable replication.

In proteins, hydrogen bonds form between the backbone oxygens and amide hydrogens. Because of H-bonding, Alpha helix and Beta sheet is able to form in proteins. This is the secondary structure. Hydrogen bonds also play a part in forming the tertiary structure of protein through interaction of R-groups.

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For making hydrogen bonds you need to have H and some highly electronegative element (like O for exp).
CH2F2 and N2H4 will exhibit the most hydrogen bonding (polar), followed with CH3OCH3 (nonpolar) which will exhibit much less H-bonding than the first two compounds.

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There are several obvious differences, the first being that hydrogen bonds have to include a hydrogen atom, where covalents exists for all elements. Second, that hydrogen has to be bonded to a a oxygen or sometimes a nitrogen. There are other less common elements such as sulfur, selenium, and phosphorus. Beyond that there are no general rules, but specific cases are studied.

So water H-O-H can have hydrogen bonding, CH3OH, methanol can have it, etc. Benzene, C6H6 can not have it. Ethyl ether CH3CH2-O-CH2CH3 can not. It has O and H, but the H’s are bonded to carbon, not O.

The strength of the weak hydrogen bonds has to be determined experimentally, but a chemist can sometimes predict based on the other atoms in the molecule.

See the references for more info.

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Hydrogen bonding is when hydrogen bonds directly to O, F and N

Only choice 5 has hydrogen bonding

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The hydrogen bonding between molecules in the solution and polar residues on the surface of the protein “exclude” the hydrophobic residues from the core of the protein, repelling them and causing them to group together on the inside of the protein, away from the hydrophilic functional groups.

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An enzyme breaks the hydrogen bond in the section of DNA that is required. Then, mRNA (messenger RNA) is created because mRNA’s base pairs match up the now single stranded DNA (because it was unzipped by the enzyme breaking the hydrogen bond). The mRNA then travels to a ribosome, which interprets the information on the mRNA (3 base pairs code for an amino acid), and constructs the protein by the instructions of the mRNA. This is done by tRNA (transfer RNA) grabbing amino acids per instruction of the mRNA and place them in order on an amino acid chain on the ribosome. When the chain is complete, the ribosome lets the amino acid chain go and the chain folds and makes a protein.