Hydrogen bonding

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sarahtang4B
Posts: 132
Joined: Fri Sep 28, 2018 12:27 am

Hydrogen bonding

Postby sarahtang4B » Sat Nov 10, 2018 2:04 pm

how does the bond length affect the melting and boiling points for H20 and H2S?

Porus_Karwa_2E
Posts: 72
Joined: Fri Sep 28, 2018 12:24 am

Re: Hydrogen bonding

Postby Porus_Karwa_2E » Sat Nov 10, 2018 2:06 pm

The increased bond length makes the bonds stronger.

Rachel-Weisz3C
Posts: 66
Joined: Fri Sep 28, 2018 12:23 am

Re: Hydrogen bonding

Postby Rachel-Weisz3C » Sat Nov 10, 2018 2:15 pm

Aside from the number of bonds (single, double, etc.), the overall length of a bond also determines how strong it is. When the bond length is larger, the bond is weaker because the atoms are further apart and therefore they can break apart easier. H2O has a bond length of about 1A and H2S has a bond length of about 2.8A. This is why H2O has a higher melting/boiling point, because its bond length is smaller than H2S's.

Jonathan Zhao 4H
Posts: 57
Joined: Fri Sep 28, 2018 12:26 am

Re: Hydrogen bonding

Postby Jonathan Zhao 4H » Sat Nov 10, 2018 3:10 pm

The electronegativity of oxygen causes water to be polar, leading to hydrogen bonding. Because of hydrogen bonding, H2O requires more energy needed to break the bonds, thus it has a much higher boiling point/melting point than that of H2S.

Elizabeth Kim 4E
Posts: 60
Joined: Fri Sep 28, 2018 12:29 am

Re: Hydrogen bonding

Postby Elizabeth Kim 4E » Sat Nov 10, 2018 7:10 pm

H20's bond length is shorter than H2S which means its harder for electrons to break apart, therefore it has a higher boiling point than H2S.

Katie_Duong_1D
Posts: 69
Joined: Fri Sep 28, 2018 12:27 am

Re: Hydrogen bonding

Postby Katie_Duong_1D » Sun Nov 11, 2018 12:13 am

H20 has hydrogen bonding and the bond length is short, so it takes more energy to break the bonds. H2S is not hydrogen bonding and the bond length is longer, so it takes less energy to break the bonds.

Nicole Elhosni 2I
Posts: 62
Joined: Fri Sep 28, 2018 12:28 am

Re: Hydrogen bonding

Postby Nicole Elhosni 2I » Sun Nov 11, 2018 10:28 am

H2O has a higher melting and boiling point because the oxygen on one water molecule forms a hydrogen bond to the hydrogen onto another water molecule. These hydrogen bonds are the reason water has a higher melting and boiling point. A solid has many bonds between molecules so when changing phases to a liquid (where there are fewer bonds between the molecules), the bonds between the molecules (the inter molecular forces) must be broken. Because hydrogen bonds are stronger than regular dipole-dipole (which H2S has), it will take more energy (a higher temperature) to break the hydrogen bonds and melt water from solid to liquid and more energy to boil water from liquid to gas. The actual polar covalent bond of the water molecule is not broken; the water stays intact, it is just changing phases.

Arshia Ramesh 1G
Posts: 35
Joined: Fri Sep 28, 2018 12:18 am

Re: Hydrogen bonding

Postby Arshia Ramesh 1G » Sun Nov 11, 2018 11:05 pm

The further apart the two atoms are (longer bond length) the easier they are to separate or break apart


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