Chemical Principles Flashcards
Atom
Smallest unit of matter which can partake in a chemical reaction
Smallest unit of matter which can partake in a chemical reaction is the
Atom
Element
Composed of one type of atom
Example of an element
Carbon, Nitrogen and Oxygen
Composed of one type of atom
element
Molecule is formed when
When 2 or more atoms join together
- the atoms can be the same or difference
- Same: N2O2
- Different: H2O
2 or more atoms joined together forms a
molecule
- atoms can be the same or be difference
Explain the atomic structure
Every atom is composed of a single centrally located nucleus which contains protons (carrying a positive charge) and neutrons (which carry no charge)
- since neutrons carry no charge, the nucleus will always carry a net positive charge
- nuclear contents do not participate in chemical reactions and thus is referred to as stable
Electrons exist outside of the nucleus is specialized regions of space called orbitals and they carry a negative charge
What is the nucleus composed of
Protons (positive charge) and Neutrons (no charge) = net positive charge
What part of the atomic structure does not participate in chemical reactions and is referred to as stable
The nucleus
What charge does the nucleus have
A net positive charge (b/c the neutrons have no charges and protons have a positive charge)
What are orbitals
specialized regions of space that exist outside of the nucleus, and electrons are in these orbitals
- carry a negative charge
ions
when an atom has an overall positive or negative charge - it is no longer netural and is referred to as an ion
- an atom that looses an electron will have a net positive charge
- When an atom gains an electron it will have a net negative charge
Cation
atoms carrying a positive charge
Anion
Atoms carrying a negative charge
Na has an atomic # of 11 and Cl has an atomic # of 17 what will happen?
an ionic bond
Na^+ and Cl^- ionic bond
Chemical bonds form…?
Why do chemical bonds exist?
What are the types of chemical bonds
- form in between atoms when electrons in their outer shells interact with one another
- every atom wants to achieve chemical stability & they do this by filling their outermost shell w/ electrons
- Atoms achieve a full complement of electrons (8) by combining to form molecules - Three types of chemical bonds found in living systems
covalent, ionic and hydrogen bonds
three types of chemical bonds
Covalent, Ionic and Hydrogen bonds
Covalent bonds
very strong bonds
- formed when two atoms come together and share electrons within their outershell
- Water is formed as a result of covalent bonds in between hydrogen and oxygen
Ionic bonds
These bonds form as a result of the attractive force in betwen ions of opposite charge
- weaker than covalent
- The attractive force holds the two atoms together in the bond
ex) NaCl
- Na requires the loss of an electron to achieve stability and CL requires the gain of an electron to achieve stability
- Cl recieves the electrons from Na rather than sharing it : Cl
- Cl becomes Cl^- and Na becomes Na^+
Hydrogen Bonds
Are also covalent bonds
These bonds form when Hydrogen is covalently bound to oxygen or another electron loving molecule such as nitrogen
*- i.e N and O are electron loving - greedy for electrons *
Since the atom bound to hydrogen is “electron loving” it holds the shared electrons closer to its nucleus than hydrogen
Explain the hydrogen bonds between
H : C and
H : O
H and C
- Non- polar covalent bond
- carbon is not more electron loving than hydrogen, thus the electrons are equally shared in between the two atoms
H and O
- polar covalent bond
- Oxygen is more electron loving than hydrogen, thus the electrons are not equally shared in between the two atoms and are held more closely to the Oxygens nucleus
- Oxygen gets a partial negative charge and hydrogen gets a partial positive charge
Explain partial positive and negative charges between atoms and Polar/non-polar molecules
they happen when there unequal sharing of electrons between two atoms resulting in Partial positive charge and a
Partial negative charge
Molecules that contain unequal sharing of electrons are polar molecules, vice versa equal sharing of electrons are non-polar molecules
Explain water with polar covalent bonds and hydrogen bonds
Water has a partial negative on the O atom, and a partial positive charge on the 2 H atoms, resulting in a polar covalent bond due to unequal sharing of electrons (electrons held closely to O)
Since theres partial + and - charges, the partial + charge on the hydrogen atom is attracted to partial - charge on atoms within another molecule = hydrogen Bond
- hydrogen bonds are weaker than both covalent and ionic - heat breaks down these hydrogen bonds
-Hydrogen bonds result in networks of molecules of different molecules
Organic compounds and inorganic compounds
organic because they contain carbon
ex. sugar, protein, DNA or RNA contain carbon
Inorganic b/c they contain no carbon and organisms need a wide variety of inorganic compounds in order to live and reproduce
ex. water
What are Inorganic compounds and provide an example
Don’t contain carbon
ex. water is the most inorganic molecule, CO2
Water is the
- most inorganic molecule found in living systems
- water accounts for approx 60-80% range that we accept for cell weight
- Water is a solvent and b/c electrons are not shared equally b/w the hydrogen and oxygen atoms it is a polar solvent
List different reasons why living things are able to make such good use of water
- Water is an excellent solvent
- Every water molecule can form Hydrogen bonds with other water moelcules
- Water is a great temperature buffer b/c of its strong hydrogen bonds
- ex. sweat - 3.4 hydrogen bonds/water molecule, heat from body = used to break h-bonds b/w water molecules of sweat, when heat is used up, the body temp goes low b/c i’ve used it
- Water is easily split into its component ion H^+ and OH^-
- This characteris allows water to play key roles in many chemical reactions
Water is an excellent solvent because
It can dissolve many ionic compounds such as NaCl
- Na+Cl- = solute - heat applied, water then surrounds the Na and CL, and Na and Cl is seperated is distributed in the solution = solution
The ions (Na+, Cl-) remain dissolved in the water and form a solution
this solution forms because the partial positive regions within the water moelcules surround the negative ions (Cl-) and the partial negative regions within the water molecule surround the positive ions (Na+) holding them in solution
Explain waters excellent ability to hydrogen bonds
Every water molecule can form four hydrogen bonds with other molecules
- the excellent ability to hydrogen bond allows water to form networks of interconnected water molecules which gives water a very high boiling point
- This high boiling point (100 C) keeps water in its liquid state in most of the places that is found on earth
what allows water to form networks of interconnected water molecules
every water molecule can form 4 hydrogen bonds w/ other molecules and these hydrogen bonds form networks of interconnected water molecules
What gives water a high boiling point
Since water is able to form interconnected networks of water molecules due to the hydrogen bonds, this gives water a high boiling point (100 C)
What happens when water molecules are heated up and what does this results to?
Heat breaks bonds when water is heated, when all 4 bond are broken, the water molecule evaportates b/c theres nothing physically holding it there in the pot
Explain what happens when water molecules start to cool after heating
When water starts to cool (after heating), the water molecules move less and are close together when they start to become a water molecule again, a liquid form again = forming hydrogen bonds
Explain when liquid water is put into a freezer and its hydrogen bonds as a liquid and solid
Liquid water in freezer = solid
- liquid water had 3.4 hydrogen bonds each (3.4 b/c some have 4 some have 3)
- Solid water (ice) - per water molecule has 4 hydrogen bonds, thats why it’s so solid
Complex organic molecules
The four outer electrons of carbon allow it to form four covalent bonds with a large number of different atoms
- there are four major classes of organic compounds found in living things (big castles made up of lego blocks (atoms))
1. Carbohydrates
2. Proteins
3. Lipids
4. Nucleic Acids