CHEM 121 Chapters 2 – 6 Answers| 100% CORRECT

CHEM 121 Chapters 2 – 6 Answers CHEM 121 Chapter 2 Answers what is the law of conservation of mass (by Lavoisier) there is no change in mass when a chemical reaction occurs What is the law of definite proportions (by Proust) a compound always contains elements combined in the same proportion by mass Ex 1.000g of water (H2O) .111g of H and .889g of O ratio is always 1:8.01 what is the atomic theory of matter and who discovered it John Dalton all matter, whether element, compound, or mixture, is composed of small, indivisible particles called atoms. Atoms are the building blocks of matter what is the first basic postulate of Dalton’s atomic theory matter is composed of tiny particles called atoms what is the second basic postulate of Dalton’s atomic theory all atoms of an element are identical in mass and other properties what is the third basic postulate of Dalton’s atomic theory atoms of different elements differ in mass and other properties what is the fourth basic postulate of Dalton’s atomic theory compounds are composed of atoms of different elements combined in fixed proportions by mass. The number of atoms of elements in a compound is a small whole number ratio what is the fifth basic postulate of Dalton’s atomic theory atoms are indestructible. Atoms are neither created nor destroyed in chemical reactions: simply rearranged to yield new substances who was a renowned scientist at the same time as Dalton who did not accept his atomic theory Sir Humphrey Davy what is the law of multiple proportions when two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in ratios of small whole numbers whose theory and what theory predicted the law of multiple proportions Dalton’s atomic theory what is an atom the smallest particle of an element that retains the chemical properties of the element how was the first subatomic particle discovered phenomenon of an electric discharge in an evacuated glass tube, gas discharge tube (Crookes Tube) what is a cathode ray tube crude television tube cathode emits an invisible ray called a cathode ray what does a cathode ray tube look like on one end there is a cathode then there is a metal shield with a slit then there is a florescent screen that will show the cathode ray then on the other side there is an anode connected on each end is a high voltage source what did JJ Thomson discover with the cathode ray tube magnetic and electric fields bend the cathode rays. suggests that they are a basic component of all matter (beam of electrons) what is the charge to mass ratio of an electron (also discovered by JJ Thomson) -1.76 x 10^8 C/g (negative because electrons have a negative charge) what date was the electron discovered April 1897 who did the oil-drop experiment Robert Millikan What was the oil drop experiment? What was the result of the oil drop experiment discovering the charge on an electron what is the charge on an electron -1.60 x 10^-19 C what is the mass of an electron 9.09 x 10^-28 g who discovered that cathode rays caused some materials to emit rays Rontgen what were the rays called that Rontgen discovered x-rays who discovered that some compounds emitted rays spontaneously without cathode ray stimulation Becquerel what did Becquerel’s discovery suggest radioactivity what other scientist also worked with Becquerel to discover radioactivity Marie Curie who discovered that there are three types of rays produced by radioactivity Ernest Rutherford what were the three types of rays that Rtherford discovered 1. Alpha rays: beams of positively charged particles 2. Beta rays: beams of negatively charged particles 3. gamma rays: high energy radiation; no charge who came up with the plum pudding model JJ Thomson what did the plum pudding model look like a uniform sphere of positively charged matter with negatively charged electrons embedded in it what did Rutherford, Geiger, and Marsden look at the scattering angles of alpha beams