HESI A2 CHEMISTRY KEY TERMS EXAM QUESTIONS

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HESI A2 CHEMISTRY KEY TERMS EXAM QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -43 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation

Question 1: Electron Clouds

Answer:

The group of electrons revolving around the nucleus of an atom; a cloud-like group of electrons

Question 2: Acid

Answer:

A compound that is a hydrogen proton donor; it is corrosive to metals, changes blue litmus paper red, and becomes less acidic when mixed with bases

Question 3: Single Replacement

Answer:

Reactions that consist of a more active metal reacting with an ionic compound containing a less reactive metal to produce a new compound

Question 4: Significand

Answer:

The base value of the number or the value of the number when all the values of ten are removed; used in scientific notation

Question 5: Fahrenheit

Answer:

A temperature measuring system only used in Belize, Jamaica, and the US and its territories; abbreviated F; rarely used for any scientific measurements except body temperature; has the following characteristics: pure water at sea level freezes at 32*F, boils at 212*F, and the avg human body temp is

98.6*F

Question 6: Compound

Answer:

The combination of two or more elements or atoms

Question 7: Base

Answer:

A hydrogen or proton acceptor and generally has a hydroxide (OH) group in the makeup of the molecule; AKA alkaline compounds and are substances that denature proteins, making them feel very slick; they change red litmus paper blue and become less basic/alkaline when mixed with acid

Question 8: Solute

Answer:

The part of a solution being dissolved

Question 9: Combustion

Answer:

A self-sustaining exothermic chemical reaction usually initiated by heat acting on oxygen and a fuel compound such as hydrocarbons

Question 10: Synthesis

Answer:

A type of chemical reaction in which two elements combine to form a product; an example is the formation of potassium chloride (KCl) salt when a solution of potassium (K) combines with chloride (Cl?)

Question 11: Decomposition

Answer:

A chemical reaction often described as the opposite of synthesis because it is the breaking of a compound into its component parts

Question 12: Chemical Equations

Answer:

Combination of elements or compounds called reactants responding to create a product or end result; equations written in the following manner: Reactants ? Products or Reactants ? Products (for reversible reactions)

Question 13: Catalysts

Answer:

Substances that accelerate a reaction by reducing the activation energy necessary for the reaction to occur

Question 14: Ionic Bond

Answer:

An electrostatic attraction between two oppositely charged ions or a cation and an anion; this bond type is generally formed between a metal (cation) and a nonmetal (anion)

Question 15: Scientific Notation

Answer:

The scientific system of writing numbers; a method to write very big or very small numbers easily; composed of three parts: a mathematic sign (+ or -) the significand, and the exponential AKA the logarithm

Question 16: Kelvin

Answer:

A unit of measure of temperature that is used ONLY in the scientific community; Kelvin (K) has the following characteristics: 0 degrees Kelvin (0 K) is ?273*C and is thought to be the lowest temperature achievable AKA absolute 0, pure water at sea level freezes at 273 K, water boils at 373 K, and most people have a body temp of 310 K

Question 17: Double Replacement

Answer:

A reaction that involves two ionic compounds; the positive ion from compound combines with the negative ion from the other compound; this results in two new ionic compounds that have "switched partners"

Question 18: Reactants

Answer:

The part of a chemical reaction that reacts to produce a desired end result or compound

Question 19: Basic Unit of Measure

Answer:

Standard unit of a system by which a quantity is accounted for and expressed: grams (g), liters (l), or meters (m)

Question 20: Solvent

Answer:

The part of a solution that is doing the dissolving

Question 21: Proton

Answer:

Part of the nucleus of an atom that has a positive electric charge

Question 22: Groups

Answer:

Elements that are placed together in columns on the periodic table

Question 23: Atomic Mass

Answer:

The AVERAGE mass of each of that element's isotopes

Question 24: Nucleus

Answer:

The positively charged mass within an atom; composed of neutrons and protons; possessing most of the mass but occupying only a small fraction of the volume of the atom

Question 25: Products

Answer:

A substance or compound created from a chemical reaction