Chapter 2 Flashcards
1
Q
Chemistry
A
the study of interactions between atoms and molecules
2
Q
Atom
A
- the smallest unit of matter that enters into chemical reactions
- atoms interact to form molecules
3
Q
Atoms are composed of:
A
- Electrons- negatively charged particles
- Protons- positively charged particles
- Neutrons- uncharged/ neutral particles
- Protons and Neutrons are in the nucleus
- Electrons move around the nucleus (electron shell)
4
Q
Chemical elements
A
- each element has a unique number of protons
- there are the same number of protons and electrons in a neutral atom
- Atomic number= number of protons
- Atomic weight = number of protons and neutrons
5
Q
Atomic symbols
A
Hydrogen-H Carbon-C Nitrogen- N Oxygen- O Sodium- Na Magnesium- Mg Phosphorus- P
6
Q
Electronic Configurations
A
- electrons are arranged in electron shells corresponding to different energy levels
- each shell has a maximum number of electrons
- electrons fill the inner-most shells first
7
Q
How atoms form molecules
A
- atoms combine to form molecules
- a molecule that contains 2 or more types of atoms is called a compound: H20
- The “2” indicates that there are 2 atoms of hydrogen combined with 1 atom of oxygen
- molecules hold together because of attractive forces. called chemical bonds, between the atomic nuclei
8
Q
Chemical Reactions
A
- involve the making or breaking of bonds between atoms
- a change in chemical energy occurs during a chemical reaction
- Endergonic- reactions absorb energy
- Exergonic- reactions release energy
9
Q
Synthesis reactions
A
- occur when atoms, ions or molecules combine to form new, larger molecules
example: A + B –>(combines to form) AB (new molecule)
Anabolism: the synthesis of molecules in a cell
10
Q
Decomposition reactions
A
- occur when a molecule is split into smaller molecules, ions or atoms
example: AB –> (breaks down into) A + B
Catabolism: the decomposition reactions in a cell
11
Q
Organic vs inorganic compounds
A
Organic- always contain carbon and hydrogen
-example: C6H12O6
Inorganic- typically lack carbon
-example: CO2, Water, Oxygen gas
12
Q
Polar Molecule (water)
A
- whole molecule is neutral
- but, one end has a negative charge and the other end has a positive charge
13
Q
water
A
- life on earth evolved based on the chemistry of water
- inorganic
- water makes up 65-75% of cells, on average
- water more easily maintains a constant temperature than many other solvents; protects cells from temperature fluctuations
14
Q
acids, bases and salts
A
- dissociate into positively charged H+ ions and negatively charged ions
- dissociate into one or more H+ ion
example: HCI–> H+ + CI-
15
Q
Bases
A
- dissociate into negatively charged hydroxyl ions OH- and positively charged ions
- one or more OH- ion
example: NaOH –> Na+ + OH-