HESI A2 CHEMISTRY ACTUAL QUESTIONS WITH CORRECT VERIFIED ANSWERS | 100% PASS (A+ CERTIFIED)

HESI A2 CHEMISTRY ACTUAL QUESTIONS WITH CORRECT VERIFIED ANSWERS | 100% PASS (A+ CERTIFIED)1. 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 2. atom the basic building block of a molecule that contains a nucleus and orbits 3. atomic mass the average mass of each of that element's isotopes 4. atomic number the number of protons in the nucleus, and it defines an atom of a particular element 2 / 17 5. 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. 6. basic unit of measure standard unit of a system by which a quantity is accounted for and expressed (grams, liters, or meters) 7. catalysts substances that accelerate a reaction by reducing the activation energy or the amount of energy necessary for a reaction to occur 8. 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. 9. 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 10. combustion a self sustaining exothermic chemical reaction usually initiated by HEAT acting on OXYGEN and a fuel compound such as hydrocarbons 3 / 17 11. compound the combination of two or more elements or atoms 12. covalent bond 2 atoms share electrons, generally in pairs, one from each atom 13. decomposition a chemical reaction often described as the opposite of synthesis because it is the breaking of a compound into its component parts 14. deoxyribose a sugar used in the formation of DNA 15. 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" 16. electron clouds the group of electrons revolving around the nucleus of an atom; a cloudlike group of electrons 4 / 17 17. equilibrium a state in which reactants are forming products at the same rate that products are forming reactants 18. 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 19. groups elements that are placed together in columns in the periodic table 20. 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) 21. 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 5 / 17 22.