1 - Water And Carbon Flashcards
chapter 2
Rank the following chemicals (most negative to least) based on their electro-negaitivity Carbon Nitrogen Oxygen Hydrogen
Oxygen
Nitrogen
Carbon = hydrogen
What are the most abundant elements on earth?
Carbon
Hydrogen
Nitrogen
Oxygen
Describe a covalent bond
A type of chemical bond where electrons are shared
Why do atoms make bonds?
To achieve stability
A desire to have their outermost shell full; therefore stable
Describe the valance electron
The electrons which react = in the outermost shell and are unpaired
What are the different types of bonds?
Covalent bonds Non-polar bonds Ionic bonds Polar covalent bonds Hydrogen bonds
Explain electro negativity
Some molecules hold electrons more tightly than others. One side of a molecule will be charged positive and the other side more negative like H2O
Describe a non-polar covalent bond
The electrons are shared =
Symmetrical
H-H
Describe covalent bond
Electrons are shared
Describe what is going on with the electrons in a polar covalent bond
Electrons are not shared equally
Asymmetrical sharing
Change of charge on either side of the molecule
Describe an ionic bond
Where electrons are transferred from one atom to another -> stable outermost shell
Has </> protons so each atom has a charge cause by balance between protons and electrons
NaCl
Describe hydrogen bond
Occurs when the positive H which is part of a polar covalent bond is attracted to another charged negative atom in another polar bond
Takes energy to break that bond to change it’s structure
What are the six properties of water?
cohesion adhesion surface tension less dense when in solid form high capacity for absorbing energy solvent
describe cohesion
binding between molecules - helps them stay together
describe adhesion
binding of unlike molecules
ie glass and water
describe solvent
ions and polar molecules become surrounded by H2O molecules -> dissolve due to partial charges
and agent for getting substances into a solution
describe surface tension
more ordered @ air - H2O interface
resistance from H2O to depress water surface
has an elastic membrane
Describe what’s going on with H2O and energy
it takes lots of energy to heat water because the first step is to break the H bonds
Is H2O more or less dense when comparing it in a liquid form to a solid
It is more dense as a solid therefore it floats
the molecules forms a crystal lattice because of the H bonds with the H2O molecules
How does Magnesium act as a laxative?
Mg+2 attracts the H2O molecules because of it’s polarity, the water is drawn from the surrounding tissue therefore moistening the stool and helping elimination
Which molecule is in the shape of a V
H2O
Name the four types of bonds in range of strongest to least
Non-polar covalent bond
Polar covalent bond
ionic
hydrogen
Name which type of bond best describes the following:
It occurs with the positive Hydrogen which is part of a polar covalent bond, when attracted to another charged negative atom in another polar bond
hydrogen bond
Describe what happens to the water molecules as NaCl disolves into h20
the H2O lines up so that the electronegative side of the molecule lines up with the Na - O
and conversely with the Cl where the H lines up around it
