HESI A2 Chemistry Latest Update 2024

HESI A2 Chemistry Latest Update 2024 What makes an atom's physical structure? A nucleus and orbits(sometimes known as electron clouds) What composes the center of the atom? Protons and neutrons What spins in the orbits of an atom? Electrons What are the energy levels of the atom called? Shells or orbits What is the term used to define an atom that is electrically charged? Ionic state. What is a cation? An atom with a positive charge What is anion? An atom with a negative charge What is the structure of the periodic table? A series of rows called periods, and columns called groups. What can be predicted by the group an element occupies? Charge and the numbers of electrons in its outer shell. What is the name and properties of group VIII of the periodic table? Noble gases. They tend to remain neutral in most situations, because their outer orbits are complete. What is the atomic number? The number of protons in the nucleus, defines an atom of a particular element. What is the atomic mass? The average mass of an element's isotopes. What are isotopes? Different kinds of the same atom that vary in weight. What is a compound? The combination of different elements. What do chemical reactions resemble? A cooking recipe. What are the reactants in a chemical reaction? The ingredients of a chemical reaction. What is the term given to the results of a chemical reaction? The products. Why must a chemical equation be balanced at the end of a reaction? Because the law of conservation of mass indicates that mass cannot be created nor destroyed in a chemical reaction. What are equilibrium reactions? Chemical reactions that stop before all the reactants are used to make the products. What causes equilibrium? The state in which reactants are forming products at the same rate that products are forming reactants. What are the four basic ways to increase the reaction rate? Increase temperature Increase the surface area of the reactants Add a catalyst Increase the concentration of the reactants. What does increasing temperature cause in a chemical reaction? The particles have greater kinetic energy, increasing the speed at which they move around, and the chance of collision between particles. How does increasing the surface area of the particles in a reaction speed chemical reactions? Gives the Particles more opportunities to come in contact with each other. What is a catalyst? An agent that accelerates a chemical reaction by reducing the activation energy or the amount of energy necessary for a reaction to occur. What is the effect of increasing the concentration of reactants in a chemical reaction? More chance collisions occur between the reactants, producing more products. What is a solution? A homogeneous mixture of two or more substances. What is a solute? The part of a solution being dissolved. What is a solvent? The part of a solution the solute is being dissolved in. What are compounds? Mixtures of different elements to create a single matter. What are alloys? Solid solutions of metals to make a new one. e.g. bronze ( a mixture between copper and tin) What are Amalgams? A specific type of alloy in which another metal is dissolved in Mercury. What are emulsions? Mixtures of matter that readily separate such as water and oil. What occurs in a synthesis reaction? Two elements combine to form a product. What occurs in a decomposition reaction? Breaks a compound into its component parts. What occurs in a combustion reaction? An exothermic (explosive) reaction occurs. Usually initiated by heat acting on oxygen and a fuel compound such as hydrocarbon. What are the products of the combustion of hydrocarbon? Carbon dioxide and water. What occurs in a single replacement chemical reaction? An ionic compound reacts with a more active metal to create a new compound. What occurs in a double replacement compound? Involves two ionic compounds The positive ion from one compound combines with the negative ion from another compound. What is the result of a double replacement compound? Two new ionic compounds that have "switched partners" AB + XY ---> AY + XB What is chemical bonding? The joining of an atom, element, or chemical to another.