Honors Chemistry Final Exam Review Exam Questions And Answers Already Graded A+

the number one decimal place smaller than the smallest given unit; must be estimated - AnswerUncertain Number how repeatable and consistent a measurement is - Answer-Precision how close to the accepted value a measurement is - Answer-Accuracy The number of protons in an atom, unique to each element, used to define an element. - AnswerAtomic Number the mass of the nucleus. also protons+neutrons - Answer-Mass Number two atoms with the same number of protons but different numbers of neutrons - Answer-Isotope an element is a substance with only one type of atom. - Answer-element homogeneous means that the mixture is completely mixed so that the naked eye can't tell the two substances apart. Heterogeneous means that you can see the two different substances w/ naked eye. - Answer-Homogeneous vs. Heterogeneous mixture a natural process that certain elements undergo that alters their nuclei and gives off rays in the form of either charged particles or energy. - Answer-radioactivity 2 protons and 2 neutrons ⁴₂α least harmful radiation - Answer-alpha particles an electron ⁰₋₁β middle harmful radiation - Answer-beta particles most harmful radiation - Answer-gamma particles opposite of electron ⁰₁β - Answer-positronwhen an atom is bombarded by particles in order to change it into a different atom - Answertransmutation the time it takes for half of a radioactive lump of stuff to go away - Answer-half-life 10^-1 - Answer-deci 10^-2 - Answer-centi 10^-3 - Answer-milli 10^-6 - Answer-micro 10^-9 - Answer-nano 10^1 - Answer-deca 10^3 - Answer-kilo 10^6 - Answer-mega 10^9 - Answer-giga mass of sample left after time T - Answer-MsubT initial mass - Answer-MsubO total time - Answer-T half-life - Answer-t1/2total time/t1/2 - Answer-# of half-lives MT=Mo/2^t1/2 - Answer-half-life formula mass/volume - Answer-density a change that doesn't change the composition of a substance - Answer-Physical change a change that changes the composition of a substance - Answer-chemical change a compound is a substance with a specific and uniform number or 2 or more atoms (H2O for example) - Answer-compound