HESI Chemistry
About this set
Created by:
lynettelacert on September 22, 2010
Subjects:
Classes:
Log in to favorite or report as inappropriate.
Order by
80 terms
Terms | Definitions |
|---|---|
 Laboratory Tests | Play an important role in the detection, identification, and management of most diseases. |
| Healthcare Professionals | A sound, basic knowledge of chemistry enables the health care professional to reduce risk and deliver safe, high-quality care. |
| 3 States of Matter | Solid, Liquid, Gas |
| Solid | A solid is matter that has definite shape and volume. |
| Liquids & Gases | Matter that is fluid and takes the shape of its container. Unlike solids and liquids, the volume of gases will change drastically with changes in temperature and pressure. |
| 2 Types of mixures | Homogeneous and Heterogeneous |
| Homogeneous Mixtures | Those with uniform density throughout and no distinguishable components. |
| Heterogeneous | Mixtures in which components are readily distinguished. |
| Physical and Chemical Changes | A physical change is one in which no change has been made to the chemical composition of the substance |
| Ex. of Physical and Chemical Changes | A good example would be the cutting of a cake. A chemical change is one in which the substance is changed by the breaking and reforming of bonds to create a new and different substance. The spoiling of an egg is a good example. |
| Element | The simplest of substances and is represented by a specific letter or combination of letters. |
| Compounds | Combination of elements in whole number ratios. |
| Periodic Table | All of the known elements can be found on the periodic table. Elements are arranged according to their chemical properties. The most important trends represented on table is the atomic number. |
| Chemical Equations | Are simply recipes. |
| Reactants | Ingredients that react to produce a desired result called products. Equations are written in the following manner: Reactants -- Products |
| The Law of Conservation of Mass | States that mass cannot be created or destroyed during a chemical reaction. Therefore, once the reactants have been written and the products predicted, the equation must be balanced. The same number of each element must be represented on both sides of the equation. |
| Chemical Reactions | The breaking of bonds and the reforming of new bonds to create new chemical compounds with different chemical formulas and different chemical properties. |
| 5 Main Types of Chemical Reactions | Synthesis, Decomposition, Combustion, Single Replacement, and Double Replacement |
| Synthesis Reaction | Two elements combine to form a product. |
| Decomposition Reaction | The breaking of a compound into component parts. |
| Combustion Reaction | The reaction of a compound or element with oxygen. In the combustion of a hydrocarbon, the products are CO2 and H2O |
| Replacement Reaction | Involve ionic compounds, and whether the reaction will take place is based on the activity of the metals involved. |
| Single Replacement Reaction | Consist of a more active metal reacting with an ionic compound containing a less active metal to produce a new compound. |
| Double Replacement Reaction | Involve two ionic compounds. The positive ion from one compound combines with the negative ion of the other compound. The result is two new ionic compounds that have "switched partners." |
| Atomic Number | Represents the number of protons a given element contains. |
| Atomic Mass | An average of the masses of each of its isotopes as they occur in nature. By subtracting the atomic number from the mass number of an element, it is possible to calculate the number of neutrons contained by a given isotope of a certain element. |
| Period Table Columns and Rows | The groups (columns) and periods (rows) are significant. It is possible to predict with accuracy the charge of an atom of certain elements when as an ion dissolved in solution or as an ion in a compound based on its location on the periodic table. |
| Atomic Structure | The atom consists of three component parts: Protons, Neutrons, and Electrons. |
| Protons | Have a positive charge |
| Electrons | Have a negative charge |
| Neutrons | Have no charge |
| Mass | Protons and neutrons have approximately the same mass. Relative to the proton, the mass of an electron is 1840 times less. The number of protons in an element is its atomic number. |
| Mass Number | The sum of the protons and neutrons in an atom. |
| Hesi Hint | It is important to note that the nucleus (dense center of the atom) contains the protons and the neutrons, whereas the electrons are located in orbitals (clouds) surrounding the nucleus. The majority of the volume of an atom is empty space. |
| Nuclear Chemistry | In chemical reactions, atoms try to reach stable electron configurations. |
| Nuclear Reactions | Are those that take place in the nucleus, to obtain stable nuclear configurations. |
| Radioactivity | Describes the emission of particles from an unstable nucleus. |
| Radiation | Particles that are emitted from an unstable nucleus. |
| Types of Radiation | Alpha, Beta, Gamma |
| Alpha Radiation | The emission of helium ions. These particles contain two protons and two neutrons, causing them to have a charge of +2. These particles are charged. Penetration from alpha particles can generally be stooped by a piece of paper. |
| Beta Radiation | A product of the decomposition of a neutron. Composed of high-energy, high-speed electrons. These particles are negatively charged and have virtually no mass. Beta particles can be stopped by aluminum foil. |
| Gamma Radiation | A high-energy electromagnetic radiation. Gamma rays lack charge and mass. This form of radiation can be stopped by several feet of concrete or several inches of lead. |
| 2 Types of Chemical Bonding | Covalent and Ionic |
| Ionic Bond | An electrostatic attraction between two oppositely charged ions. This type of bond is generally formed between metals and nonmetals. |
| Single Covalent Bond | Formed when two atoms share a pair of electrons. |
| Double Covalent Bond | Formed when two electron pairs are shared. |
| Triple Covalent Bond | Formed when three electron pairs are shared. |
| Covalent Bond | The strongest of any type of chemical bond. It is generally formed between nonmetals.. If the electrons in the bond are shared equally, then the bond is nonpolar. However, not all elements share electrons equally within a bond. When this occurs, a polar covalent bond is the result. |
| Polarity | Based on the difference in electronegativity values for the elements involved in the bond. The greater the difference, the more polar the bond will be. |
| Intermolecular Forces | Other types of attractions between particles. These forces are hydrogen bonding, dipole interactions, and dispersion forces. |
| van der Waals forces | Dipole interactions and dispersion forces. |
| Hydrogen Bonds | The attraction for a hydrogen atom by a highly electronegative element. The elements involved are fluoride, chlorine, oxygen, and nitrogen. Hydrogen bonds are the strongest of the intermolecular forces. |
| Dipole Interactions | The attractions of one dipole for another. Created when an electron pair in a covalent bond is shared unequally. The result is a bond in which the more highly electronegative element is slightly negative and the less electronegative element is slightly positive. The positive end of a dipole in one compound will be attracted to the negative end of another dipole in a separate compound. This attraction is considered a weak intermolecular force. |
| Dispersion Forces | The weakest of all intermolecular forces. Moving electrons within an element or compound concentrate themselves on one side of an atom. This causes a momentary dipole, which would be attracted to another momentary dipole in an adjoining element or compound. Usually found in nonpolar covalent compounds. |
| Mole | The amount of a substance that contains 6.02x10(23) representative particles of that substance. |
| Dozen | Used to represent the number twelve. The mass of one mole of a substance is called the atomic mass and can be found on the periodic table. |
| Stoichiometry | The part of chemistry that deals with the quantities and the numeric relationship between compounds in a chemical reaction. |
| Coefficients | For a chemical equation to be balanced, numbers called coefficients are placed in front of each compound. These numbers are used in a ratio to compare how much of one substance is needed to react with another in a certain reaction. The process is similar to comparing ingredients in a recipe. |
| Equilibrium | Chemical reactions which slows down with leftover amounts of reactant still present. At this point, reactants are forming products at the same rate that products are forming reactants. The reaction is said to be reversible. |
| 4 Ways to Increase Reaction Rate | Increase the Temperature; Increase the Surface Area, Increase the Concentrations of Reactants, Or Add a Catalyst |
| Increasing the Temperature | Causes the particles to have a greater kinetic energy, thereby enabling them to move faster and have a greater chance of contact. The contact is when chemical reactions occur. |
| Increasing The Surface Area | Gives particles more opportunity to come into contact with one another. Wood is an excellent example. Taking a log and cutting it into shavings or sawdust increases the rate of its reaction with the surrounding oxygen. Therefore the wood ignites and burns faster. |
| Measuring Concentrations in Several Ways: Weight or Mass Per Volume Unit | Measured by the weight or mass per volume unit, which is the amount of solute per volume of solution. This method is most often used when describing a solid that is being diluted by a liquid. |
| Measuring Concentrations in Several Ways: Volume Per Unit Volume | Used when one liquid is diluted with another liquid. |
| Measuring Concentrations in Several Ways: Percentage | Can be used with either liquids or solid chemicals. |
| Measuring Concentrations in Several Ways: Molarity of the Solution or The Gram-Molecular Mass Of A Compound Per Liter of Solution | ... |
| Measuring Concentrations in Several Ways: Osmolarity | Or the number of osmoles of solute per liter of solution. When the concentration is increased, the rate of the reaction is accelerated. Conversely when the concentration is decreased, the rate of the reaction is reduced. |
| HESI Hint | Concentrations have a great deal to do with the rate of reaction. As is the case with males and females, increasing the numbers of reactants (persons) means that a greater number of collisions can take place. |
| Catalysts | Accelerates a reaction by reducing the activation energy, or the amount of energy necessary for a reaction to occur. The catalyst is not used up in the reaction and can be collected on reaction completion. Usually, a car battery produces electricity. However, when the battery is being charged, the opposite is true. The battery then stores electricity in the form of chemical energy. |
| Redox | Oxidation and Reduction reactions are coupled together in a single term - redox. Redox reactions involve the transfer of electrons from one element to another. It is not possible to have one without the other. |
| Oxidation | Loss of electrons |
| Reduction | The gain of electrons. |
| Steps to Determine Oxidation | The oxidation number of any elemental atom is zero. Most elements in their standard states are single atoms, but a few exceptions exist. Those exceptions are H, Br, O, N, Cl, I, and F. These elements, when existing alone, are always in pairs. Oxygen would be O2, and so forth. |
| ... | The oxidation number of any simple ion is the charge of the ion. If in a reaction sodium were listed as an ion, Na+, it would have an oxidation number of +1. If chlorine were listed as an ion, Cl-, it would have an oxidation number of -1. |
| ... | The oxidation number for oxygen in a compound is -2. |
| ... | The oxidation number for hydrogen in a compound is +1. |
| ... | The sum of the oxidation numbers equals the charge on the molecules or polyatomic ions. |
| Acids | Those compounds acting as hydrogenion donors. Acids produce H3O+ in aqueous solutions, they taste sour or tart, most of their formulas begin with H, they release H2(g) when reacting with active metals, they conduct an electrical current, and they have a pH value less than 7. |
| Bases | Those compounds acting as hydrogen ion acceptors. They produce OH- in aqueous solutions, they taste bitter, they feel slippery, they conduct electricity, their formulas often contain OH- in their names, and their pH is greater than 7. |
| HESI Hint | By manipulation of the quantity of acid and/or base in a solution, the pH can be altered. The process of neutralization occurs when an acid and a base react to produce a salt and water. Generally, this results in a neutral pH or pH close to 7. |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.