CHEM 100 Exam 2 Questions With 100% Guaranteed Answers A+ Pass.

oxyacid - correct answers an acid with a main atom, oxygen, and one or more hydrogen atom Acid - correct answers a substance that has a proton that can be removed by a water molecule when in a water solution Hydronium ion - correct answers H₃O⁺ positively charged hydrated hydrogen ion produced when an acid ionizes in water what can X (a negatively charged ion produced when the acid ionizes) be? - correct answers - may be a monatomic ion (Ex: Cl⁻) - may contain oxygen (Ex: NO₃) - may be an ion that contains hydrogen how is an acid represented? - correct answers Represented as HX, H2X, or H3X, where X is any negatively charged ion produced when the acid ionizes HX+H₂O→H₃O+X⁻ strong acid - correct answers - an acid that donates every hydrogen ion to a water molecule - almost all of the molecules of the original compound react and very few remain as unionized molecules - excellent conductors of electricity - major species are ions, minor species are unionized molecules weak acid - correct answers - an acid that donates hydrogen ions only to a certain extent (not all hydrogen ions dissociate) - poor conductors of electricity - major species are unionized molecules, minor species are ions major species - correct answers chemical particle present in greatest abundance in acid solution minor species - correct answers chemical particle present in lesser abundance in acid solution 7 common strong acids - correct answers sulfuric acid (H₂SO₄) hydrochloric acid (HCl) nitric acid (HNO₃) perchloric acid (HClO₄) chloric acid (HClO₃) hydrobromic acid (HBr) hydroiodic acid (HI) what to remember when describing acids as "strong" and "weak" - correct answers the words "strong" and "weak" do not refer to the corrosiveness of the acid, they refer to the extent to which the acid dissociates what causes conductivity in an ionic solution? - correct answers movement of ions; the ability of a solution to conduct electricity is regarded as evidence that it contains ions Strong electrolyte - correct answers substance whose solution is a good conductor of electricity Weak electrolyte - correct answers substance yields a solution that conduct electricity, but poorly permitting only dim glow of light bulb - low concentrations of ions in their solutions nonelectrolyte - correct answers substance whose solution is a nonconductor of electricity - no ionic movement formation of ionic compounds - correct answers - form from a metal and a nonmetal - the metal atom gives one or more electrons to the nonmetal atom→ the result is a metal cation and a nonmetal anion - they stay together by electrostatic attraction, an ionic bond what happens when ionic compounds dissolve in water? - correct answers its ions separate from each other and get surrounded by water molecules Ex) Write the dissolving equation for K2SO4(s) - K2SO4→ 2K+(aq) + SO42-(aq) *note that it dissolves into IONS when are ions the major species in a solution? - correct answers in all soluble ionic compounds AND in the seven strong acids when are neutral molecules the major species in a solution? - correct answers everything else, but primarily in compounds with all nonmetal atoms (molecular compounds), weak acids, water conventional equation - correct answers total ionic equation - correct answers replacing the formulas of the dissolved substances with the major species in solution; includes spectator ions spectator ions - correct answers ions present at the scene of a reaction but experiences no chemical change net ionic equation - correct answers ionic equation from which all spectators have been removed; indicates exactly the chemical change that takes place writing a net ionic equation - correct answers 1. Write and balance the conventional equation, including state symbols 2. Write the total ionic equation by replacing each aqueous substance that is a strong acid or a soluble ionic compound with its major species. Do not separate a weak acid into ions, even though its state is aqueous. Do not change/separate solids, liquids, or gasses into ions. Be sure the equation is balanced in both atoms and charge 3. Write the net ionic equation by removing the spectators from the total ionic equation. Reduce coefficients to lowest terms, if necessary. Be sure the equation is balanced in both atoms and charge. Ion-combination reaction - correct answers formation of a product compound by a cation from one reactant combining with an anion from another Activity series - correct answers - lists metal elements and hydrogen in order of reactivity in a single-replacement redox reaction - any element in the table will replace the dissolved ion of any element beneath it - note that Zn is above Cu on the activity series; this means that Zn replaces Cu in a single-replacement reaction, but Cu will not replace Zn in a solution Single replacement oxidation-reduction (redox) reactions - correct answers Electrons are transferred from one species to another oxidized species - correct answers - loss of electrons - increase in oxidation number reduced species - correct answers - gain of electrons - decrease in oxidation number oxidation number - correct answers number assigned to each element in a species that is used to keep track of electrons oxidation number assignment rules - correct answers 1. Free elements have an oxidation number of 0. Oxidation numbers can be referred to as an oxidation state; so free elements have an oxidation state of 0. 2. The sum of oxidation states of all the atoms in a species (compound or polyatomic ion) must equal the net charge of the species. 3. In compounds, Group I metals like Na and K have an oxidation state of +1. 4. In compounds, fluorine always has an oxidation state of -1 bc it is the most electronegative element. 5. Group II metals are always assigned an oxidation state of +2, and Group III ions are assigned an oxidation state of +3. These states are identical with the ionic charges of these elements. 6. Hydrogen in compounds has an oxidation state of +1. 7. Oxygen in compounds has an oxidation state of -2. writing ion charges vs. oxidation states - correct answers the charge of an ion is written as 1+ or 2+. The oxidation state is written +1 and +2 and so on to differentiate them from ionic charge how to calculate oxidation numbers of the elements in a compound - correct answers 1. write the formula with space between the symbol of the elements or ions. place the oxidation number of each element or ion beneath its symbol. use "n" for the unknown oxidation number. 2. multiply each known oxidation number by the number of atoms of that element in the formula unit. 3. set "n" and the oxidation numbers = to the charge on the species, and solve for "n" How to identify molecular-product reactions - correct answers One reactant is a strong acid and one product is water or a weak acid neutralization reaction - correct answers acid and base react to yield water, which is neutral, that is neither an acid nor a base double-replacement reactions that form unstable products - correct answers 3 ion combinations yield molecular products that are not the products one would expect; one must be alert when they appear! [REVISE] wavelength - correct answers measurement from crest to crest on a wave - If the wavelength is long, then the number of cycles is less - If the wavelength is shorter, the number of cycles is more frequency - correct answers From crest to crest is one cycle of a wave. If we count how many cycles pass a point per second, this is the frequency of a wave at what speed do all waves travel? - correct answers speed of light what is included in the electromagnetic spectrum? - correct answers - Gamma rays and X-rays - Ultraviolet, visible, and infrared light - Microwaves, radio waves, and long radio waves order of wavelength - correct answers wave equation - correct answers Waves are described by its properties which includes velocity (v or c), wavelength (λ), and frequency (ν) c = λ×ν continuous spectrum - correct answers light from standard light bulbs, known as white light, produces a continuous spectrum when passed through a prism line spectrum - correct answers spectral lines that appear when light emitted from a sample is analyzed in a spectroscope discrete lines - correct answers separate lines of color to indicate that they are individually distinct wave-particle duality - correct answers when light moves through space it acts like a wave, but when light is emitted or absorbed it acts like a particle (Einstein) the Bohr Model of the hydrogen atom: explanation - correct answers - Niels Bohr thought that electrons should be moving around the nucleus like tiny satellites - For a hydrogen atom, energy of its electron and the radius of its orbit are quantized - Bohr reasoned that these lines show that electrons exist at only certain energy levels in relationship to the nucleus - Electron transitions of differing energies produce different wavelengths of light