HESI A2 Chemistry Latest Update 2024

HESI A2 Chemistry Latest Update 2024 Acid a compound that is a hydrogen or proton donor. It is corrosive to metals, changes blue litmus paper red, and becomes less acidic when mixed with bases atom the basic building block of a molecule that contains a nucleus and orbits atomic mass the average mass of each of that element's isotopes atomic number the number of protons in the nucleus, and it defines an atom of a particular element base a hydrogen or proton acceptor and generally has a hydroxide (OH) group in the makeup of the molecule. Bases are also called alkaline compounds and are substances that denature proteins, making them feel very slick; they change red litmus paper blue and become less basic when mixed with acids. basic unit of measure standard unit of a system by which a quantity is accounted for and expressed (grams, liters, or meters) catalysts substances that accelerate a reaction by reducing the activation energy or the amount of energy necessary for a reaction to occur Celsius a temperature system used in most of the world and by the scientific community; It has these characteristics: zero degrees = freezing point of pure water at sea level 100 degrees = boiling point of pure water at sea level. Most people have a body temperature of 37 degrees Celsius. chemical equations combination of elements or compounds called reactants responding to create a product or end result. Equations are written in the following manner: reactants ---> products. The arrow can go the other way or both ways combustion a self sustaining exothermic chemical reaction usually initiated by HEAT acting on OXYGEN and a fuel compound such as hydrocarbons compound the combination of two or more elements or atoms covalent bond 2 atoms share electrons, generally in pairs, one from each atom decomposition a chemical reaction often described as the opposite of synthesis because it is the breaking of a compound into its component parts deoxyribose a sugar used in the formation of DNA double replacement a reaction that involves two ionic compounds. The positive ion from one compound combines with the negative ion of the other compound. The result is the two new ionic compounds that have "switched partners" electron clouds the group of electrons revolving around the nucleus of an atom; a cloudlike group of electrons equilibrium a state in which reactants are forming products at the same rate that products are forming reactants fahrenheit a temperature measuring system used only in the US, its territories, Belize, and Jamaica. It is rarely used for any scientific measurements except for body temperature. It has these characteristics: 0 degrees is the freezing point of sea water or heavy brine at sea level; 32 degrees F is the freezing point of pure water at sea level; 212 degrees F is the boiling point of pure water at sea level; most people have a body temperature of 98.6 F groups elements that are placed together in columns in the periodic table ionic bond an electrostatic attraction between two oppositely charged ions or a cation and an anion. This type of bond is generally formed between a METAL (cation) and a NON-METAL (anion) isotope different kinds of the same atom that vary in weight; for a given element, the number of PROTONS=SAME, while the number of neutrons = varies to make the different isotopes kelvin a unit of measure that is used only in the scientific community. Kelvin has these characteristics: 0 degrees Kelvin = -273 degrees C and is thought to be the lowest temperature achievable or absolute zero (0); the freezing point of waer is 273 degrees K; the boiling point of water is 373 K; most people have a body temperature of 310 degrees K mole a way to express concentrations of atoms. It is 6.02 x 10^23 of particles nucleus the positively charged mass within an atom, composed of PROTONS & NEUTRONS and possessing most of the mass but occupying only a small fraction of the volume of the atom periodic table a table that organizes the elements based on their structure and thus helps predict the properties of each of the elements. It is made up of a series of rows called periods and columns called groups periods a series of ROWS within the periodic table that classify the elements prefix Prefixes are quantifiers of the measurement units. All prefixes are based on multiples of 10. Any of the prefixes can be comined with one of the basic units of measurement products a substance or compound created from a chemical reaction reactants the part of a chemical reaction that reacts to produce a desired end result or compound ribose sugar used in the formation of RNA significand the base value of the number or the value of the number when all the values of ten are removed. Used in scientific notation single replacement reactions that consist of a more active metal reacting with an ionic compound containing a less active metal to produce a new compound solute the part of a solution that is being dissolved; the DRUG solvent the SOLUTION that is doing the dissolving