CHEM 115: Practice Exam Questions & Answers 2024/2025

CHEM 115: Practice Exam Questions & Answers 2024/2025 Matter - ANSWER-Anything physically real; Has mass and occupies space Chemical Composition - ANSWER-Describes what matter is made of Chemical Reactivity - ANSWER-Describes how matter behaves Physical Changes - ANSWER-Doesn't alter the chemical makeup of a substance EX) Ice melting Chemical Changes - ANSWER-Does alter the substance's chemical make up EX) Wood burning Solid - ANSWER-Has a definite volume and shape Liquid - ANSWER-Has a definite volume but a indefinite shape Gas - ANSWER-Has neither a definite volume or shape Pure Substance - ANSWER-Uniform in it's chemical composition and it's properties EX) sugar, water, baking soda Mixture - ANSWER-Varies in both composition and properties (Depending on how it's made) Homogeneous Mixture - ANSWER-Has same uniform composition throughout Can’t always tell by looking at it if it's a pure substance or a homogeneous mixture EX) Sugar in water Heterogeneous Mixture - ANSWER-Non-uniform that has regions of different composition Easy to distinguish between pure substance and heterogeneous mixture EX) Vegetable soup Element - ANSWER-A fundamental substance that can be broken down into simpler substances EX) Hydrogen, Oxygen, Aluminum, Gold 118 discovered; 91 occur naturally Chemical Compound - ANSWER-A pure substance that can be broken down into simpler substances by chemical reactions EX) Electricity turning water into just hydrogen and oxygen Metals - ANSWER-Good conductors of heat & electricity Solid at room temperature Left side of the Periodic Table Malleable Nonmetals - ANSWER-Poor conductors of heat & electricity On the right side of the Periodic Table Metalloids - ANSWER-Have properties of both metals and nonmetals Brittle as a solid Conductivity of both a metal and nonmetal Separates metals and nonmetals Mega- - ANSWER- Kilo- - ANSWER- Milli- - ANSWER- Micro- - ANSWER- Nano- - ANSWER- Pico- - ANSWER- Mass - ANSWER-A measure of the amount of matter in an object Weight - ANSWER-A measure of the gravitational pull that the Earth or other large body exerts on an object Depends on where you are while mass always stays the same Specific Heat - ANSWER-Amount of heat that will raise the temperature of 1g of a substance by 1 degree C Calories/ Grams x Degree C Density - ANSWER- Atom - ANSWER-The smallest and simplest particle of an element Four Fundamental Assumptions (Atomic Theory) - ANSWER--All matter is composed of atoms, -Atoms of a given element differ from those of other elements, -Chemical compounds consist of atoms combined in specific ratios, -Chemical reactions change only the way that atoms are combined in compounds Subatomic Particles - ANSWER-Protons Neutrons Electrons Atomic Mass Unit (amu) - ANSWER-A convenient unit for describing the mass of an atom EX) An atom of Carbon 6 protons, 6 neutrons= 12 amu Nucleus - ANSWER-The dense, central core of an atom that contains protons and neutrons Atomic Number (Z) - ANSWER-The number of protons in atoms of a given el continues...