Honors Chemistry Chapter 3 Practice Questions and Answers

Honors Chemistry Chapter 3 Practice Questions and Answers What is the Law of Conservation of Mass? - Answer️️ -The law that states that mass cannot be created or destroyed in ordinary chemical and physical changes. What is the Law of Definite Proportions? - Answer️️ -The law that states that a chemical compound always contains the same elements in exactly the same proportions by weight or mass. What is the Law of Multiple Proportions? - Answer️️ -The law that states that when two elements combine to form two or more compounds, the mass of one element that combines with a given mass of the other is in the ratio of small whole numbers. Who came up with the atomic theories in 1808 and what were they? - Answer️️ -John Dalton 1. All matter is composed of extremely small particles called atoms. 2. Atoms of an element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties. 3. Atoms cannot be subdivided, created, or destroyed. 4. Atoms of different elements combine in simple whole-number ratios to form chemical compounds. 5. In chemical reactions, atoms are combined, separated, or rearranged (These are not all correct) ©SOPHIABENNETT 2024/2025 9:45 AM Page | 2 What is the modern definition of an atom? - Answer️️ -The smallest unit of an element that maintains the chemical properties of that element. What observations were made when current was passed through a Cathode-Ray Tube? - Answer️️ -1. Cathode rays were deflected by a magnetic field in the same manner as a wire carrying electric current, which was known to have a negative charge. 2. The rays were deflected away from a negatively charged object. These observations led to the hypothesis that the particles that compose cathode rays are negatively charged. It was also concluded that electrons are present in atoms of all elements. Based on what was learned about electrons, what two other conclusions were made about atomic structure? - Answer️️ -1. Because atoms are electrically neutral, they must contain a positive charge to balance the negative electrons. 2. Because electrons have so much less mass than atoms, atoms must contain other particles that account for most of their mass. In 1911 why were Ernest Rutherford and Hans Geiger and Erne