Chemistry Honors Midterm Review

Chapter 1

Define:

Matter- anything that has mass and takes up space; mass is a measurement that reflects the amount of matter.

The thoughts and ideas that fill your head are not matter, neither is heat, light, radio waves, or magnetic fields.

Hypothesis- a tentative explanation for what has been observed.

Control- a standard for comparison in an experiment.The constant.

Theory- an explanation that has been supported by many many experiments.

Conclusion- a judgment based on the information obtained.

Scientific Law- a relationship in nature that is supported by many experiments.

Differentiate Between:

Mass / Weight:Weight- a measure not only of the amount of matter but also of the effect of

Earth’s gravitational pull on that matter.

Mass- a measurement that reflects the amount of matter.

Weight is not constant and changes in different locations.Mass is constant and doesn’t change. (Law of conservation of Mass)

Precision / Accuracy:Accuracy- how close the measured value is to an excepted matter.Precision- refers to how close a series of measurements are to one another.

Chapter 2

The rules of significant figures:Multiplication and Division: when you multiply or divide numbers your answer

must have the same number of significant figures as the measurement with the lowest amount of significant figures.

Addition and Subtraction: when you add or subtract measurement your answer must have the same amount of digits to the right of the decimal point as the value with the fewest digits to the right of the decimal point.

Metric Prefixes:

Prefix Symbol Factor Scientific Notation

Example

giga G 1 000 000 000 109 gigameter (Gm)mega M 1 000 000 106 megagram

(Mg)kilo K 1000 103 kilometer (km)deci D 1/10 10-1 deciliter (dL)centi C 1/100 10-2 centimeter (cm)milli M 1/1000 10-3 miligram (mg)micro µ 1/1 000 000 10-6 microgram (µg)nano N 1/1 000 000 000 10-9 nanometer (nm)pico P 1/1 000 000 000 000 10-12 picometer (pm)

Define and calculate density:Density- a ratio that compares the mass of an object to its volume.

Chapter 3

Differentiate between:

Chemical / Physical Changes:Chemical Change- a process that involves one or more substances changing into new substances.Physical Change- a process that alters a substance without changing its composition.

Chemical Change Physical ChangeExplodeRustOxidizeCorrodeTarnishFermentBurnRot

BendGrindCrumpleSplitCrush

Heterogeneous / Homogeneous:Heterogeneous- a mixture that does not blend smoothly throughout and in which the individual substances remain distinct.Homogeneous- a mixture that has a constant composition throughout; always has a single phase.

Mixtures / Solutions:Mixture- combination of two or more pure substances in which each pure substance retains its individual chemical properties.Solution- also known as Homogeneous mixtures; a uniform mixture that may contain solids, liquids or gases.

Define Chemical and Physical Properties:Chemical Property- the ability of a substance to combine with or change into one or more other substances.Physical Property- characteristic that can be observed or measured without changing the samples composition.

Extensive Properties- properties dependent on the amount of substance present.Intensive Properties- properties independent of the amount of substance present.

Extensive Properties Intensive PropertiesMassVolumeLength

Density

Physical Properties Chemical PropertiesDensityColorOdorTasteHardnessMelting PointBoiling PointConductivity

Reactivity with Substances

Properties of:

Metals Nonmetals MetalloidsShiny when smooth and cleanSolid at room temperatureGood conductors of heat and electricity

Generally Gases or brittleDull looking solidsPoor Conductors of heat and electricityOnly nonmetal that is liquid at room temperature is Bromine (Br)

Physical and Chemical properties of both Metals and Nonmetals

Methods of Separating Mixtures:Filtration- a technique that uses a porous barrier to separate a solid from a liquid.Distillation- used to separate homogeneous mixtures mostly, it is a separation technique that is based on differences in the boiling point of the substances involved; in distillation a mixture is heating until the substance with the lowest boiling point boils to a vapor that can be condensed into a liquid and collecting.Crystallization- a separation technique that results in the formation of pure solid particles of a substance from a solution containing a dissolved substance. When the solution contains as much dissolved substance as it can possibly hold the addition of a tiny amount often causes the dissolved substance to come out of a solution and collect as crystals on some available surface.Chromatography- a technique that separates the components of a mixture (called the mobile phase) on the basis of the tendency of each to travel or be drawn across the surface of another material (called the stationary phase).

Chapter 4

Define and explain the formation of alpha and beta particles:Alpha particles- a particle with two protons and two neutrons with a +2 charge; is equivalent to a helium(-4) nucleus, can be represented as α, and is emitted during radioactive decay.

A new element Radon- 222 is created as a result of the alpha decay of the unstable Radium- 226 nucleus.Beta particles- a high speed electron with a -1 charge, that is emitted during radioactive decay. Can be represented as β.

The beta decay of unstable carbon- 14 results in the creation of a new Nitrogen- 14 atom.

Nuclear reactions- reactions which involve a change in an atoms nucleus.Radioactivity- process where substances spontaneously emit radiation.Radiation- the rays and particles emitted by the radioactive material.Radioactive decay- when an unstable nuclei loses energy by emitting radiation in a spontaneous process (a process that does not require energy).** By emitting radiation, atoms of one element can change into atoms of another element.

Page 107

Radiation Type Symbol Mass (amu) ChargeAlpha 4 +2Beta -1Gamma 0 0

Nuclear equation: Top # - Mass NumberBottom # - Atomic Number

Gamma Radiation?

Define:Isotope- atoms with the same amount of protons but different number of neutrons.Atomic Number- number of protons in an atom.

Mass Number- represents the sum of the number of protons and neutrons in the nucleus.

Know the contributions of:

Democritus Matter is composed of empty space through which atoms move.Atoms are solid, homogeneous, indestructible, and indivisible.Different kinds of atoms have different sizes and shapes.The differing properties of matter are due to the size, shape, and movement of atoms.Apparent changes in matter result from changes in the groupings of atoms and not from changes in the atoms themselves.

Dalton All matter is composed of extremely small particles called atoms.All atoms of a given element are identical, having the same size, mass, and chemical properties. Atoms of specific element are different from those of any other element.Atoms cannot be created, divided into smaller particles, or destroyed.Different atoms combine in simple whole- number ratios to form compounds.In a chemical reaction, atoms are separated, combined, or rearranged.

Thompson Performed cathode ray experiments to measure the electron’s charge to mass ratio. Thompson concluded that the mass of the charged particle was less than that of a hydrogen model, the lightest known atom. Dalton was wrong; Atoms were divisible into smaller subatomic particles.Proposed the plum pudding model.

Rutherford Famous for his gold foil experiment.Determined that:Atom contain:Mostly empty spaceTiny, dense nucleus which is positively charged

Creates new nuclear model of atom:Atom contains:Mostly empty spaceTiny, dense nucleus which is positively charged

Creates new nuclear model of atom:

Percent Abundance- the abundance of the isotope that naturally occurs in nature.

Calculate atomic mass given percent abundance and AMU:

Multiply percent abundance of each given Isotope by its respective AMU value. Sum the values to determine the Atomic mass. Use the periodic table to determine the element.

Chapter 5

Define principal quantum number:principal quantum number- the minimum amount of energy that can be gained or lost by an atom.Describe the orbitals and sub-levels present in various quantum numbers:

Principal quantum number (n)

Sub-levels (types of orbitals) present

Number of orbitals related to sub-level

Total number of orbitals related to principal energy

level (n2)1 s 1 1

2 sp

13

4

3 spd

135

9

4 spdf

1357

16

Determine maximum number of electrons within principal quantum number:

Atomic Sub-levels Number of Electrons

s 2

p 6

d 10

f 14

Based on the quantum number determine the energy level:Equantum = hvPlanck’s Constant (h)=6.626 x 10-34J·s

Differentiate between excited and ground state based on electron configuration:

Bohr (1913) proposed why the emission spectrum of hydrogen is not continuous.Electrons can have only certain “energy states” Ground State - the lowest allowable energy state.Excited State – energy state of an atom when it gains energy .

Define spectral lines:spectral lines- light given off at a specific frequency by an atom or molecule.

When an electron drops from a higher energy orbit to a lower energy orbit a photon with a specific energy is emitted.

Describe the shapes of the:

Define electron dot structure:Electron-dot structure consists of the elements symbol which represents the atomic nucleus and inner level electrons, surrounded by dots representing the atoms valence electrons.

Construct an electron dot structure:

Draw an electron dot diagram:

???????

Calculate:Frequency of Electromagnetic radiation- Wavelength of Electromagnetic radiation-Energy of a photon- Frequency of a photon-

λ- wavelengthm- massv- frequency / velocityh- planks constant

EM Wave relationship- c = λhEnergy of a quantum- Equantum= hvEnergy of a photon- Ephoton= hv

de Broglie’s equation- λ =

Chapter 6

Differentiate between and define group and period:Group- series of columns (vertical).Period- rows (horizontal).

Define and give trends for:Electronegativity- relative ability of its atoms to attract electrons in a chemical bond. (Decreases going down, Increases going across)

Ionization Energy- energy required to remove an electron from a gaseous atom. (Decreases going down, Increases going across)Electron Affinity- the ability of an atom to attract additional electrons.Atomic Radius- the radius of an atom. (Increases going down, decreases going across)

Be familiar with the placement and definitions of:Transition metals- Groups 1B through 8B. Possess a wide range of chemical and physical properties.Alkali metals- Group 1A elements except hydrogen. Chemically reactive.Alkaline earth metals- Group 2A elements. Chemically reactive.Nobel Gasses- Group 8A. Extremely unreactive. Halogens- Group 7A. Highly reactive.Inner transition metals- two sets of transition metals, known as the lanthanide and actinide series, located along the bottom of the periodic table.

Define Electron Configuration:electron configuration- the arrangement of electrons in an atom.

Chapter 7List characteristics of various elemental / families:

Alkali Metals 1A Shiny gray solids soft enough to be cut by a knife. Good conductors of heat and electricity.

Alkaline Earth metals 2A Shiny solids harder then alkali metals. Form compounds with oxygen besides BeO2. Most compounds of Earth metals do not easily dissolve in water.

Boron Group 3A Always found combined with other elements in nature. Most often found as oxides in earth’s crust.

The Carbon Group 4A Has a wide mix of metalloids, nonmetals, and metals giving it a wide range of properties

The Nitrogen Group 5A Each element might have 5 valence electrons, but each has a unique physical

and chemical property. Ex. Antimony and Bismuth expand when they change from a liquid to a solid.

Oxygen Group 6A With 6 valence electrons the elements act mainly as nonmetals

Halogens 7A Can form compounds with almost all metals. These are all salts.

Noble Gases 8A Colorless and un reactive, made them hard to find by scientists. Very stable elements.

Chapter 8

Define term ion:ion- An atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

Differentiate between a cation and anion:cation- positively charged ion.anion- negatively charged ion.

Describe the composition of ionic compounds and list their characteristics:The positive and negative ions are packed into a regular repeating pattern that balances the forces of attraction and repulsion.

Often crystal lattice is formed- a three-dimensional geometric arrangement of particles.Ionic Crystals have high melting points and boiling points.

They are hard, rigid, and brittle solids due to the strong attraction between their ions.

Charged particles must be free to move for a material to conduct an electric current.

In the solid state, ionic compounds are nonconductors because of the fixed position of ions.The formation of ions is always exothermic.

Determine the probable charge of an element based on its periodic placement:

**Look at periodic Table

Construct the electron configuration for various ions:**Common Sense

Define and give examples for:Ionic bond- the electrostatic force that holds oppositely charged particles together in an ionic compound. Usually, Nonmetal- MetalMetallic bond- the attraction of a metallic cation for delocalized electrons. Ex, Metals

Name compounds containing ions and polyatomic ions:**Polyatomics

Construct chemical formulas based on chemical name:**Study Nomenclature

Chapter 9

Name covalent compounds using numeric prefixes:

Number of atoms Prefix Number of atoms Prefix

1 mono- 6 hexa-

2 di- 7 hepta-

3 tri- 8 octa-

4 tetra- 9 nona-

5 penta- 10 deca-

Write the formula for a covalent compound from its name:**Common Sense

Construct Lewis structures compounds:**Review (+Exceptions)

Determine (Shape, Bond Angle, Polarity, Hybrid Orbital):

Define covalent bond and explain how one works:

Covalent bond- the chemical bond that results from the sharing of valence electrons, and it works by sharing a certain amount of electrons between atoms and the shared electrons are considered be part of the complete outer energy level of both atoms involved

Define coordinate covalent bond and explain how one works:Coordinate covalent bond-

1. a small group of molecules has an odd number of valence electrons and cannot form an octet around each atom. For example, NO2 has five valence electrons from nitrogen and 12 from oxygen, totaling 17 which cannot form an exact number of electron pairs.

2. some compounds form with fewer than eight electrons present around an atom. This group is relatively rare, and BH3 is an example. When one atom donates a pair of electrons to be shared with an atom or ion that needs 2 electrons to become stable. It works because atom or ions will loan pairs often form coordinate covalent bonds with atoms or ions that need 2 more electrons.

3. The 3rd group of compounds that does not follow the octet rule has central atoms that contain more than eight valence electrons. This electron formation is called an expanded octet. Example of expanded octet is PCl5.

VSEPR theory:Valence Shell Electron Pair Repulsion model. The model is based on a arrangement that minimizes the repulsion of shared and unshared pairs of electrons around the central atom. The repulsions among electron pairs in a molecule result in atoms resulting at fixed angles to each other. Valence shell electron pair repulsion (VSEPR) theory is a model in chemistry used to predict the shape of individual molecules based upon the extent of electron-pair electrostatic repulsion.

Define hybrid orbitals:hybridization- a process in which atomic orbitals are mixed to form new identical hybrid orbitals.Often called an sp3 orbital.

Describe the polarity of molecules and the formation of bonds between them:Hydrogen- always polarPolar molecules- the unequal sharing of electrons in a covalent bond.

List the characteristics of covalent bonded molecules:They are very strong.Covalent bonds are molecules (neutral) Do not conduct electricity or heatLow melting and boiling points Are less soluble in water and more soluble in non-aqueous solvents.

Chapter 10

Determine the information that can be determined from a balanced equation.The balanced equation tells you what elements are involved and in what quantities (# of moles of each element)

List the indicators that a chemical reaction has occurred.Color ChangePrecipitate FormedBubbles FormedOdorGas given off

Determine the spontaneity of a reaction.????

Determine the driving force of reactions.In single replacement reactions, the metal will not always replace another metal in a compound dissolved in water. This is because metals differ in reactivity. The metal that is doing the replacing has to be higher in the activity series than the metal that was originally part of the compound.In double replacement reactions, a driving force can be that a liquid or precipitate forms. There is no driving force when the reactants and the products are both aqueous so no reaction occurs.

Define spectator ions.They are ions in a reaction that don’t take part in the overall reaction. They remain unchanged on both sides of the chemical equation.

Balance chemical equations and predict their products.Metal+water=baseNonmetal+water=acidMetal Chlorate=Metal Chloride + OxygenOxide+Carbon Dioxide=CarbonateMetallic Oxide=Metal+Oxygen

Chapter 11

Moles to grams: Multiply by molar massGrams to moles: Divide by molar massMolecules to moles: Divide by Avagadro’s Number (6.02*10^23)Moles to molecules: Multiply by Avagadro’s NumberGrams to molecules: Divide by molar mass and then multiply by Avagadro’s NumberMolecules to grams: Divide by Avagadro’s Number, Multiply by molar mass

Determine the:Molar Mass of compounds: look on periodic tablePercent Composition: Divide mass of one element by mass of entire molecule and multiply by 100Molecular Formula:

1. Get everyone into moles2. Mole Ratio: divide by smallest mole number3. If comes out to 1.3, multiply by 3; 1.5, multiply by 24. Determine Empirical Formula5. Determine Empirical Formula Mass (look on periodic table)6. Find multiplier: Molar Mass/Empirical Formula Mass7. Multiply everything in Empirical Formula by multiplier

Hydrates:1. Subtract mass of hydrate before and after heating to get mass of water.2. Convert mass of water and mass of hydrate after heating to moles3. Divide by smaller amount of moles4. The number you get after dividing the moles of water by the smaller

amount of moles will be the number of molecules of water in your formula5. Write the formula of the hydrate with a dot and the number you get in step

4 in front of H20

Empirical Formula: see Molecular Formula

Chapter 12

Define the Law of Conservation of MassThe mass of the reactants has to equal the mass of the products in a chemical reaction. Mass cannot be created nor destroyed, it only changes form.

Limiting Reagent- the substance which is least in abundance (or amount in moles); dictates the maximum amount of product that can be formed

Excess Reagent- the substance that is not fully consumed in the reaction.

Determine the limiting and excess reagent from given data.1. Balance equation2. Convert reactants to moles3. The substance that has less moles is the limiting reagent and the other

substance is the excess. (you can then use the moles of the limiting reagent to find out how much product is formed and how much of the excess reagent is actually used in the reaction.)

Define Percent Yield and calculate it from given data.The ratio of the actual yield to the theoretical yield expressed in a percent.Theoretical Yield-the maximum amount of product that can be produced from a given amount of reactant (what you find out in your stoichiometric calculations)Actual Yield-the amount of product actually produced when the chemical reaction is carried on in an experiment (from experimental data)