Chemistry 103 Exam 1 Study Guide Questions and Answers with complete solution

The Law of Definite Proportions states that in a given chemical compound, the elements are always combined in the same proportions by _______________ - Answer-mass The Law of Conservation of mass states that no detectable gain or loss of mass occurs in chemical reactions. Mass is _______________. - Answer-conserved Dalton's atomic theory states that matter consists of tiny particles called _____________ - Answer-atoms Dalton's theory also states that atoms are ____________: in chemical reactions, atoms can rearrange but they do not themselves break apart. - Answer-indestructable Dalton's theory also states that in a given compound the constituent atoms are always present in the same fixed numerical ____________ - Answer-ratio Electrons are ___________ charged, protons are ______________ charged, and neutrons are _________________. - Answer-negatively, positively, neutral Electrons are much _______________ than protons and neutrons - Answer-smaller Protons and neutrons are found within the _____________ of an atom - Answer-nucleus In a neutral atom, the number of ____________ and _______________ must be equal. - Answerprotons, electrons The atomic number f an atom = its number of _______________ - Answer-protons the mass number of an atom = ___________+____________ - Answer-protons, neutronsIsotopes vary only in the number of ___________________ - Answer-neutrons ___________ is defined as anything that occupies space and has mass - Answer-matter _______ refers to how much matter there is in a given object, whereas ___________ refers to the force with which the object is attracted by gravity - Answer-mass, weight ____________ ____________ are transformations that alter the chemical compositions of substances - Answer-chemical reactions Substances that cannot be decomposed into simpler materials by chemical reactions are called ____________ - Answer-elements Elements and compounds are examples of ________ ___________, the composition of which is always the same, regardless of its source. - Answer-pure substances _____________ can have variable compositions - Answer-Mixtures A ________________ mixture has the same properties throughout the sample and is called a ________________ - Answer-homogeneous; solution A ___________________ mixture consists of two or more regions, called _____________ that differ in properties - Answer-heterogeneous; phases Formation or separation of a mixture into its components can be accomplished by a _____________ change, which formation or decomposition of a compound takes place by a ___________ change that changes the chemical makeup of the substances involved. - Answer-physical; chemical A ________ property is one that can be observed without changing the chemical makeup of a substance, while a ________ property describes how a substance undergoes a chemical change/reaction. - Answerphysical; chemical____________ properties are independent of sample size, while ____________ properties depend on sample size. - Answer-Intensive; extensive What are the SI base units for length, mass, time, and temperature? - Answer-Length: Meter Mass: Kilogram Time: Second Temperature: Kelvin