Chapter 3 - Molecules, Compounds, And Chemical Equations Flashcards
The properties of a compound are ____ from the constituent elements.
Totally different (think H20 vs 0)
____ ____ are forces of attraction between atoms.
Chemical bonds
The bonding attraction comes from attraction between ____ and ____.
Protons and Electrons
___ bonds result when electrons have been transferred between atoms.
Ionic
When do Ionic bonds generally occur?
When metal atoms bond to nonmetal atoms.
____ bonds result when two atoms share some of their electrons.
Covalent
When do covalent bonds generally occur?
When nonmetal atoms bond together.
The number of ____ is written to the right of the element as a subscript.
Atoms
- Gives the relative number of atoms of each element in a compound.
- Does not describe how many atoms, the order of attachment, or shape.
- Used for ionic compounds
Empirical Formula
- Gives the actual number of atoms of each element in a molecule of a compound.
- Does not describe the order of attachment, or the shape.
Molecular Formula
- Uses lines to represent covalent bonds and shows how atoms in a molecule are connected or bonded to each other.
- does not directly describe the 3D shape.
Structural Formula
Uses balls to represent the atoms and sticks to represent the attachments between them.
Ball-and-stick Models
Uses interconnected spheres to show the electron clouds of atoms connecting together.
Space-filling Models
Elements whose particles are single atoms
Atomic Elements
Elements whose particles are multi-atom molecules
Molecular Elements
Compounds whose particles are molecules made of only nonmetals
Molecular Compounds
Compounds whose particles are cations and anions
Ionic Compounds
____ elements occur as 2 atom molecules.
Diatomic
What is the rule of 7?
- Remember Hydrogen
- Go to Nitrogen (7)
- Move 2 to the side and then 3 down
- this creates a 7
Classify each of the following as either an atomic element, molecular element, molecular compound, or ionic compound
1) Aluminum, Al
2) Aluminium Chloride, AlCl3
3) Chlorine, Cl2
4) Acetone, C3H6O
5) Carbon Monoxide, CO
6) Cobalt, Co
1) Atomic Element
2) Ionic compound
3) Molecular Element
4) Molecular Compound
5) Molecular Compound
6) Atomic Element
Because we must balance the charge, if Na+ is combined with S2-, you will need ____ Na+ ions for every ____ S2-, therefore the formula must be ___
2 Na+ for every 1 S2-, resulting in Na2S
What is the Formula steps for Ionic Compounds?
1) Write the Symbol for the Metal cation and it’s charge
2) Write the Symbol for the nonmetal anion and it’s charge
3) Charge (without sign) becomes subscript for the other ion
4) Reduce subscripts to smallest whole number ratio
5) Check that the sum of the charges of the cations cancels the sum of the anions
What are the formulas for compounds made of the following ions?
1) Potassium ion with a nitride ion
2) Calcium ion with a bromide ion
3) Aluminum ion with a sulfide ion
1) K3N
2) CaBr2
3) Al2S3
To name a cation:
1) Metal with invariant charge =
2) Metal with variable charge=
3) Polyatomic ion =
1) Metal name
2) Metal name (charge)
3) Memorize
To name an anion:
1) Nonmetal =
2) Polyatomic ion =
1) Stem of nonmetal name + ide
2) Memorize
Naming Binary Ionic Compounds for Metals with Invariant Charge
1) Name Metal cation first, Name nonmetal anion
2) cation name is the metal name
3) nonmetal name is changed by adding -ide
Ex: CsF = Cesium Fluoride
Name the following compounds:
1) KCl
2) MgBr2
3) Al2S3
1) Potassium Chloride
2) Magnesium Bromide
3) Aluminum Sulfide
Naming Binary Ionic Compounds for Metals with variable charge
1) Name Metal cation first, Name nonmetal anion second
2) Metal cation name is the metal name followed by a Roman number in parentheses to indicate the charge
3) Nonmetal anion named by changing the ending on the nonmetal name to -ide
Name the following compounds:
1) TiCL4
2) PbBr2
3) Fe2S3
1) Titanium(IV) Chloride
2) Lead(II) Bromide
3) Iron(III) Sulfide
What are the formulas for compounds made from the following ions?
1) Copper(II) Ion with a Nitride Ion
2) Iron(II) Ion with a Bromide Ion
1) Cu3N2
2) FeBr2
____ are ionic compounds containing a specific number of waters for each formula unit.
Hydrates
In a formula, attached waters follow ___.
•, Ex: CoCl2•6H20
In name attached waters indicated by ____ + hydrate after name of ionic compound.
Prefix, Ex: Cobalt(II) Chloride Hexahydrate
Hydrate Prefixes
1) hemi
2) mono
3) di
4) tri
5) tetra
6) penta
7) hexa
8) hepta
9) octa
1) 1/2
2) 1
3) 2
4) 3
5) 4
6) 5
7) 6
8) 7
9) 8
Writing Names of Binary Molecules Compounds of Two Nonmetals
1) Write Name of first element in formula
a) element furthest left and down
b) use the full name of the element
2) Writes Name the second element in the formula with an -ide suffix
3) Use prefix in front of each name to indicate the number of atoms
a) Never use the prefix mono- on the first element
Name the following binary molecules:
1) BF3
2) NO2
3) PCl5
4) I2F7
1) Boron Trifluoride
2) Nitrogen Dioxide
3) Phosphorus Pentachloride
4) Diiodine Heptafluoride
Write Formulas for the Following:
1) Dinitrogen Tetroxide
2) Sulfur Hexafluoride
3) Diarsenic Trisulfide
1) N204
2) SF6
3) As2S3
What are some qualities of Acids?
- Molecular compounds that form H+ when dissolved in water
- Sour taste
- Dissolve many metals (not noble metals)
- Formula generally starts with H, Ex: HCl
____ Acids habe H+1 cation and nonmetal anion (only two elements).
Binary
____ have H+ cation and polyatomic anion.
Oxyacids
Naming Binary Acids
- Write a hydro prefix
- Follow with the nonmetal name
- Change ending on nonmetal name to -ic
- Write the wird acid at the end of the name
Name the binary acid HCl(aq)
Hydrochloric Acid
Naming Oxyacids
- If polyatomic ion Name ends in -ate, then change ending to -ic suffix
- If polyatomic ion Name ends in -ite, then change ending to -ous suffix
- Write wird acid at the end of all names
Name the oxyacid H2SO4(aq)
Sulfuric Acid
What are the formulas for the following acids?
1) Chlorous acid
2) Phosphoric Acid
3) Hydrobromic Acid
1) HClO2
2) H3PO4
3) HBr
How many moles are in 50.0g of PbO2? (Pb = 207.2, O = 16.00)
0.209molPbO2
What is the Mass of 4.78x1024 NO2 molecules?
365gNO2
What can the percentage composition be determined by?
- The formula of the compound
* The experimental mass analysis of the compound
Formula for Percent Composition
Percentage = (part/whole) x 100%
Find the mass percent of Cl in C2Cl4F2
69.58%
The ____ ____ tells you the mass of a constituent element in 100g of compound.
Mass percent
Benzaldehyde is 79.2% carbon. What mass of benzaldehyde contains 19.8g of C?
25.0g benzaldehyde
Which formula is the simplest, whole-number ratio of the atoms of elements in a compound?
Empirical Formula
Finding an Empirical Formula
- Convert the percentages to grams (100g)
- Convert grams to moles
- Write a pseudo formula using moles as subscripts
- Divide all by smallest number of moles
- Multiply all mole ratios by number to make all whole numbers
Determine the Empirical Formula of Stannous fluoride,which contains 75.7% Sn (118.70) and the rest fluorine (19.00)
Sn1F2
Determine the Empirical Formula of magnetite, which contains 72.4% Fe (55.85) and the rest oxygen (16.00)
Fe3O4
What do you need to determine the molecular formula?
You need to know the Empirical also formula and the molar mass of the compound.
Benzopyrene has a molar mass of 252 g/mol and an empirical formula of C5H3. What is its molecular formula? (C =12.01, H= 1.01)
(252 g/mol/63.08 g/mol) = 4
- A common technique for analyzing compounds is to burn a known mass of compound and weight the amounts of product made.
- Generally used for organic compounds containing C, H, O.
Combustion Analysis
- Involve chemical changes in matter resulting in new substances
- Involve rearrangement and exchange of atoms to produce new molecules
Chemical Reactions
• Shorthand way of describing a reaction
• Provides information about
- Formulas of reactants and products
- States of reactants and products
- Relative numbers of reactants and product molecules that are required
- Can be used to determine weights of reactants used and products that can be made
Chemical Equations
Methane gas burns to produce ___ ___ gas and ____ ____.
Dioxide gas and gaseous water
Whenever something burns it combines with
O2(g)
To show the reaction obeys the Law of Conservation of Mass the equation must be
Balanced
The (g) after the Formulas tells us the ____ of the chemical
State
The number in front of each substance tells us the numbers of those molecules in a reaction
Coefficients
An equation is balanced if
There are equal numbers of atoms of each element on the reactant and product sides
Symbols indicating the state after chemicals
1) (g)
2) (l)
3) (s)
4) (aq)
1) gas
2) liquid
3) solid
4) aqueous = dissolved in water
Energy symbols used above the arrow for decomposition reactions
1) D
2) hn
3) shock
4) elec
1) heat
2) light
3) mechanical
4) elec
Write a balanced equation for Al(s) + O2(g) = Al2O3(s)
4Al(s)+3O2(g)= 2Al2O3(s)
Write a balanced equation for
Al(s) + 6HC2H3O2(aq) = Al(C2H3O2)3(aq) + 3H2(g)
2Al(s) + 6HC2H302(aq) = 2Al(C2H302)3(aq) + 3H2(g)
In the 18th Century, compounds from living things were called
Organic
In the 18th Century, compounds from the nonliving environment were called
Inorganic
____ compounds easily decomposed and could not be made in the 18th Century lab
Organic
____ compounds were very difficult to decompose, but were able to be synthesized
Inorganic
Today we commonly make ___ compounds in the lab and find them all around us.
Organic
Organic compounds are mainly made out of
Carbon and Hydrogen, sometimes with O, N, S, P
Carbon atoms bond almost exclusively
Covalently
When Carbons bonds, it forms ____ covalent bonds
4
Carbon is unique in that it can form ___ chains of C atoms, both straight and branched, and rings of C atoms.
Limitless
What are the 2 main categories of organic compounds?
Hydrocarbons and functionalities hydrocarbons
___ contain only C and H
Hydrocarbons
Most files are mixtures of
Hydrocarbons
What are some common hydrocarbons?
Methane, Propane, n-Butane, n-Pentane, Ethene, and Ethyne
