Unit 2: Ch 3-4 Flashcards
1
Q
Mixture
A
elements can mix in any proportions (ie Hydrogen, H2, O2)
2
Q
Compound
A
- elements combine in fixed, definite proportions (ie H2O)
- atoms held together by chemical bonds that result from the attractions between the charged particles (electrons & protons) that compose atoms
3
Q
Ionic bonds
A
- occur between metals & nonmetals
- involve the transfer of electrons from the metal atom to the nonmetal atom
- metal ion becomes a cation
- nonmetal ion becomes an anion
4
Q
T/F
Oppositely charged ion do not attract one another by electrostratic forces and form an ionic bond
A
False
They do attract one another
5
Q
T/F
In the solid phase, the ionic compound is composed of a lattice, a regular 3-D array, of alternating cations and anions
A
True
6
Q
Covalent bonds
AKA molecular compounds
A
- occur between 2+ nonmetals
- share electrons between them, composing a molecule
7
Q
Compound’s chemical formula
define, list 3 types
A
- indicates the elements present in the compound and the relative # of atoms or ions of each
- 3 types
- empirical
- molecular
- structural
8
Q
Empirical formula
A
- gives the relative # of atoms of each element in a compound & is typically determined experimentally, yielding the lowest common multiple of elements relative to one another
- communicates the least information
9
Q
Molecular formula
A
- gives the actual # of atoms of each element in the molecule of a compound
10
Q
Structural formula
A
- uses lines to represent covalent bonds and shows how atoms in a molecule are connected or bonded to each other
- can also show the molecule’s geometry or shape
- communicates the most information
11
Q
Molecular models
list & describe
A
- molecular model: more accurate & complete way to specify a compound
- ball-and-stick model: atoms as balls & chemical bonds as stick. Reflects molecule’s shape
- space-filling model: atoms fill the space between each other to more closely represent a best est for how a molecule might appear if scaled to visible size
12
Q
Atomic elements
A
- exist in nature with single atoms as their basic units
- most elements fall into this category (ie Na, Ne, K, Mg)
13
Q
Molecular elements
A
- do not normally exist in nature with single atoms as their basic units
- they exist as molecules, 2+ atoms of the element bonded together
14
Q
Molecular compounds
A
- usually composed of 2+ covalently bonded nonmetals
- basic units are molecules composed of the constituent atoms
- ie water is composed of H2O, dry ice is CO2, propane is C3H8 molecules
15
Q
T/F
Molecular compounds contain highly directional covalent bonds, which result in the formation of molecules. Ionic compounds contain nondirectional ionic bonds, which result in the formation of ionic lattices
A
True
16
Q
T/F
Ionic compounds sometimes contain positive & negative ions
A
False
They always contain positive & negative ions
17
Q
T/F
In a chemical formula, the sum of the charges of the cations & anions must balance and is a neutral charge
A
True
18
Q
T/F
The formula of an ionic compound reflects the smallest whole-number ratio of ions
A
True
19
Q
T/F
The atomic mass of the representative elements can be predicted from their group numbers
A
False
It is the charges, not atomic mass
20
Q
T/F
The representative elements can be predicted from their group numbers
A
True
21
Q
T/F
The represented element form 1+ type of charge
A
False
They form only 1 type of charge
22
Q
T/F
Transition metals tend to form multiple types of charges and therefore cannot be predicted as in the case of most representative elements
A
True
23
Q
List the 2 types of ionic compounds
A
- type I
- type II
24
Q
Type I ionic compound
A
- metal forms only 1 type of ion
- contain a metal whose charge is invariant from one compound to another when bonded with a nonmetal anion
- the metal ion always has the same charge
25
Type II ionic compound
* metal forms more than 1 type of ion
26
Polyatomic ions
* group of ionic compounds that contain ions that are themselves **composed of a group of covalently bonded atoms** with an overall charge
* Most are **oxyanions** containing oxygen and another element
27
Oxyanions naming rules
* if there are only 2 ions in the series, the following suffixes are used:
* -ate (the one w/more oxygen atoms)
* -ite (the one with fewer)
* if there are 2+ ions in the series, the following prefixes are used:
* hypo- (less than)
* per- (more than)
28
Hydrated ionic compounds
* ionic compounds containing a specific # of water molecules associated with each formula unit
29
# insert chart from ch3 slide 24
30
# insert chart ch3 slide 25
31
Molecular compounds
* composed of 2+ nonmetals
* prefixes are the same as those used in naming hydrates
32
Acids
* molecular compounds that release hydrogen ions (H+) when dissolved in water
* composed of hydrogen and 1+ nonmetals
33
Naming binary acids
* start with hydro-, follow with nonmetal base name, add -ic
* write the word acid at the end of the name
34
Naming oxyacids
## Footnote
Ref Ch3 slide 30 illustration
* if polyatomic ion name ends in -ate, change ending to -ic
* if it ends in -ite, change ending to -ous
* write acid at the end of all names
35
# Writing formula for acids
Hydro- means that it is a...
binary acid
36
# Writing formula for acids
No prefix means that it is an...
oxyacid
37
What pollutants form acids when mixed with water, resulting in acidic rainwater?
* NO
* NO2
* SO2
* SO3
| Can fall or flow into lakes & streams, making them more acidic
38
# Ch3 slide 33 chart
39
Molecular mass/weight
Mass of the individual molecule or formula unit & is the **sum of the masses** of each constituent atom
40
Molar mass
* mass, in grams, of 1 mol of its molecules or formula units & is numerically equivalent to its formula mass with units of g/mol
41
What can molar mass in combination with Avogadros Number be used to determine?
* number of atoms in a given mass of the element
* use molar mass to convert to the amount of moles
* use Avogadros Number to convert to # of molecules
42
What can a chemical formula, in combination with the molar masses of its constituent elements, indicate?
* relative quantities of each element of a compound
* mass % of each element in a compound can be determined from the formula of the compound & the experimental mass analysis of the compound
43
What does the chemical formula show?
* relationship between the number of atoms & molecules (or moles of atoms & molecules)
* can be used to determine the amounts of constituent elements & molecules
44
Empirical formula
* smallest whole number ratio of the atoms or moles of elements in a compound
* not a ratio of masses
* determined by elemental analysis
45
How to find the empirical formula
1. convert the % to grams
2. convert grams to moles
3. write a pseudoformula
4. divide all by the smallest number of moles
5. multiply all mole ratios by a number to make all whole numbers
46
List & describe the 2 types of compounds
* **organic**
* originate from living things
* easily decomposed, cannot be be made in lab
* major components of living orgs
* composed of mainly C and H, sometimes O, N, P, S
* key element is C
* **inorganic**
* originating from the earth
* difficult to decompose, but can be synthesized
47
Carbon atoms
* bond almost exclusively covalently
* when C bonds, it forms 4 covalent bonds
48
2 categories of organic compounds
* hydrocarbons
* only contain carbon & H
* compose common fuels (ie oil, gasoline)
* functionalized hydrocarbons
49
Hydrocarbons naming
* only single bonds = alkanes
* a double bond = alkenes
* a triple bond = alkynes
* base & suffix of -ane, -ene, -yne)
50
# Ch3 slide 52 chart
Hydrocarbon base names
51
Octane
* element of gasoline
* based on the naming conventions:
* 8 carbons present
* single bonds
52
Propene
* used in the manufacture of plastics
* based on the naming conventions:
* 3 carbons present
* at least 1 double bond
53
Functionalized hydrocarbons
* derives from the functionality or chemical character that is imparted to an organic compound
54
# ch3 slide 55 - make table
