Chapter 2 - Chemical Level Flashcards
What is matter?
Anything that occupies space and has mass
What is chemistry?
The science of the structure and interactions of matter
What is mass?
Is the amount of matter in any object
Does not change
What is weight?
The force of gravity acting on matter
Does change
Matter exists in what three states?
- Solid - definite shape and volume
- Liquid- definite volume and assume the shape of its container
- Gas - neither definite shape nor volume
What are chemical elements?
Building blocks of all living and non living things.
Cannot be split into simpler substances by ordinary chemical means
What are the 4 major elements?
Oxygen (o), carbon (c), hydrogen (h), and nitrogen (n)
What are atoms?
The smallest unit of matter that retains the properties and characteristics of the element
(Each element is made up of atoms)
What is the nucleus of an atom?
The dense central core of the atom.
A subatomic particle.
What is the nucleus made of (in atoms)?
- Neutrons - no charge
2. Protons - positive charge
What are electrons?
Tiny, negatively charged particles that float around the nucleus, do not follow a fixed path or orbit but form a “cloud”
How many electrons can each shell house?
First shell - 2
Second shell - 8
Third shell - 18
18 in each shell after that.
An atom has the same number of what?
Protons (+) and electrons (-)
Which means that it doesn’t have an electrical charge, each atom is neutral.
What determines an atoms atomic number?
Number of protons
What is the mass number?
Sum of its protons and neutrons.
Example: sodium has 11 protons and 12 neutrons, therefore the mass number is 23
What is an isotope?
Atoms of the same element that have different numbers of neutrons and therefore different mass numbers.
They have the same chemical properties because they have the same number of protons and electrons.
What is a radioactive isotope?
Some isotopes are unstable; their nuclei decay (spontaneously change) into a stable condition.
As they decay, they emit radiation
What is half-life?
The time required for an isotope for half of the radioactive atoms in the sample of that isotope to decay into a more stable form.
What is the standard unit of measurement for measuring the mass of atoms?
Daltons (atomic mass unit, amu)
What is the atomic mass or atomic weight?
The average mass of all of its naturally occurring isotopes
What is an ion?
Is an atom that has a positive or negative charge b/c it has an unequal number of protons and electrons
What is ionization?
The process of giving up or gaining electrons
What is a molecule?
A combination of two or more atoms sharing electrons
What is a compound?
A substance that contains atoms of two or more different elements, examples: water, sodium chloride
The molecule of oxygen is NOT a compound because it only has one element
What is a free radical?
An atom or a group of atoms with an unpaired electron in the outermost shell
Highly unstable, highly reactive and destructive to nearby molecules
May break apart important body molecules
What are chemical bonds?
The force that holds together the atoms of a molecule or a compound
What is the valence shell?
The outermost shell
What determines whether or not an atom will form a chemical bond?
The number of electrons in its valence shell.
8 - is stable, will not bond
7 - bonds easily, room for one electron
What is the octet rule?
One atom is more likely to interact with another if doing so leaves both with 8 valence electrons
What are the three kinds of chemical bonds?
- Ionic bonds
- Covalent bonds
- Hydrogen bonds
What is an ionic bond?
The force of attraction that hold together ions with opposite charges is an ionic bond.
What is a cation?
A positively charged ion
What is an anion?
A negatively charged ion
What is an electrolyte?
An ionic compound that breaks apart into positive and negative ions in a solution
What is a covalent bond?
Forms when two or more atoms SHARE electrons.
By sharing 1, 2, or 3 valence electrons
More sharing = stronger bond
(Rather than gaining or losing them)
What is a single covalent bond?
When two atoms share one electron pair
What is a double covalent bond?
When two atoms share two pairs of electrons
What is a triple covalent bond?
When two atoms share three pairs of electrons
What is a non-polar covalent bond?
Two atoms share electrons equally
Bonds between two identical atoms are always non-polar
What is a polar covalent bond?
The sharing of electrons between two atoms UNEQUALLY
The nucleus of one atom attracts the shared electrons more strongly than the nucleus from the other atom
Partial negative charge, partial positive charge.
(Water!)
What are hydrogen bonds?
Forms when a hydrogen atom with a partial positive charge attracts the partial negative change of electronegative atoms, most often oxygen or nitrogen.
Cannot bind atoms into molecules, not very strong
What is cohesion?
The tendency of like particles to stay together
Cohesion of water gives for a very high surface tension
What is a chemical reaction?
Occurs when new bonds form or old bonds break between atoms
Total mass of reactants must equal that of products
What are reactants?
The starting substances in a chemical reaction
What are the products?
The ending substances of a chemical reaction
What is metabolism?
All the chemical reactions occurring in the body
What are the three different kinds of energy? Describe them.
- Potential energy - energy stored by matter due to its position
- Kinetic energy - energy associated with matter in motion
- Chemical energy - a form of potential energy that is stored in the bonds of compounds and molecules
What is the law of conservation of energy?
Energy can neither be created or destroyed, it may be converted from one form to another.
What are exergonic reactions?
Release more energy than they absorb
What are endergonic reactions?
Absorb more energy than they release
What is activation energy?
The collision energy needed to break the chemical bonds of the reactants
What two things influence the chance that a collision will occur and cause a chemical reaction?
- Concentration - more particles, greater chance
2. Temperature - higher temp, particles move more, greater chance
What is a catalyst, what does it do?
Chemical compounds that speed up chemical reactions by lowering the activation energy needed for the reaction to occur.
Most important catalysts in the body are enzymes.
What are synthesis reactions?
When two or more atoms, ions, or molecules combine to form new and larger molecules.
What is anabolism?
Anabolic reactions are usually endergonic b/c they absorb more energy than they release.
All synthesis electrons that occur in your body are referred to as anabolism.
What are decomposition reactions?
Reactions that split up large molecules into smaller atoms, ions, molecules.
What is catabolism?
The decomposition reactions that occur in your body are referred to as catabolism.
Usually exergonic b/c they release more energy than they absorb.
What are exchange reactions?
They consist of both synthesis and decomposition reactions.
AB + CD –> AD + BC
What are reversible reactions?
The products can revert to the original reactants