Module 2 : Introduction to Chemistry Flashcards
What are the major elements in the body and how much of the total body mass do they represent?
Oxygen, Carbon, Hydrogen and Nitrogen. They represent 96% of our body weight
What are the lesser elements which add up to 98.5% of our body weight ?
Calcium and phosphorus
For what percentage of body mass do the trace elements account ?
0.4%
What is the mass number of an atom ?
The total number of protons and neutrons
What is an ion ?
An atom with an unequal number of electrons and protons
What is an isotope ?
An atom of a specific element with the same number of protons and electrons, but different number of neutrons
What is a radioactive isotope ?
An isotope that is unstable and emits radiation (energy)
What do we call two or more different atoms that come together ?
A compound
What is a molecule ?
When two or more atoms share electrons
What is the difference between ion and free radical ?
An ion is a charged atom. A free radical is also charged, but can be an atom or molecule. It’s particularity is that a single free unpaired electron is in its outer shell.
How can a free radical be stabilized ?
By giving up the unpaired electron or taking one from another molecule.
What is the use of antioxydants ?
To inactivate oxygen-derived free radicals
Place the types of chemical bonds in order of strength
Hydrogen bonds, ionic bonds and covalent bonds
What is an ionic bond ?
When two ions of opposite polarity attract each other and exchange electrons
In what state is an ionic compound generally found ?
Solid
What is called an ionic compound that when dissolved in liquid breaks into cations and anions?
An electrolyte
What is covalent bonding ?
The sharing of electron pairs in a molecule
What is polar covalent bonding ?
A covalent bond, but with unequal sharing of electrons, creating a direction of the charge
How do hydrogen bonds form ?
The polar covalent bonding of hydrogen to oxygen or nitrogen creates a positive partial charge, because hydrogens does not attract electrons very strongly. This partial positive charge will bond to partial negative charges from other molecules. This is the hydrogen bond.
What is the role of hydrogen bonds ?
- Provide the 3-dimensional shape of proteins and enzymes.
- Bond specialized molecules such as hormones and enzymes
What is potential energy ?
The nergy stored by matter due to its position
What is chemical energy ?
Form of potential energy stored in bonds of compounds or molecules
What is kinetic energy?
Energy associated with matter in motion
When do a chemical reaction occur?
When new bonds are formed or old bonds break between atoms
What is a synthesis reaction and what is its other name ?
It’s a reaction when two or more atoms, molecules or ions combine to form a new and larger molecule. It’s also called an anabolic reaction
Give an example of a synthesis reaction
The synthesis of water from oxygen and hydrogen molecules
What is a decomposition reaction ?
A reaction where a complex molecule is broken down to smaller parts
How is called a decomposition reaction in the body?
Catabolic
What is oxidation ?
When a molecule looses an electron
What is reduction ?
When a molecule gains an electron
What happens to the potential energy of the molecule if it gets oxidized, and if it gets reduced ?
Potential energy decreases in oxidations and increases in reduction
What happens in an oxidation-reduction reaction ?
An electron is taken from the oxidized atom by the reduced atom
What are the differences between organic and inorganic compounds ?
Inorganic compounds are usually simple molecules, bound by ionic or covalent bonds. Organic molecules, are more complex structures, always composed or carbon and hydrogen, always have covalent bonds, and usually contain oxygen,
Give examples of inorganic compounds
Water, acids, salts, bases
Give the main organic compounds of the body
Carbohydrates, lipids, proteins, nucleic acids, adenosine triphosphate
What is the most important inorganic compound in all living systems ?
Water
What is the most important property of water and what does it allow ?
Its polarity. It allows the molecules to be a very versatile solvent. Its bent shape allows the molecules to interact with several ions or molecules.
What is the difference between hydrophilic and hyrophobic compounds ?
Hydrophilic molecules are charged or contain polar covalent bonds and dissolve easily in water. Hydrophobic molecules are composed mainly of non-polar covalent bonds and do not dissolve in water
How is the dissolvant property of water useful in the body?
It can enable reactants to form products or dissolve wastes