University:
Kentucky State University
Course:
CHE 101 | General Chemistry I
Academic year:

2021
Views:

374

Pages:

2
Author:

Lily Callahan

**Chemistry and Measurement** **1.1 Modern Chemistry** * Chemistry is the science of the composition and structure of materials and of the changes that materials undergo. **1.2 Experiment and Explanation** * An "experiment" is an observation of natural phenomena carried out in a controlled manner. * Results can be duplicated to get to these, variables should be controlled. * After a series of experiments, researchers might see some relationship or regularity in the results. (If the regularity or relationship is fundamental, we call it a LAW.) * A "law" is a concise statement or mathematical equation about a fundamental relationship or regularity of nature. * Example: Law of Conservation of Mass * Sometimes, scientists try to make sense of the results by giving an explanation. * "Explanations" help us organize knowledge and predict future events. * A "hypothesis" is a tentative explanation of some regularity of nature. **Hypothesis** When a hypothesis successfully passes many tests, it becomes known as a "theory." * A "theory" is a tested explanation of basic natural phenomena. Experiment and Explanation (2 aspects of science) are closely related. Experiments ⟶ Explanations 1.3 Law of Conservation of Mass Chemists began to use the balance as a tool in research. "Balance measures mass." "Mass is the quantity of matter in a material." "Matter is everything around us and takes up space." Lavoisier, a French chemist, demonstrated the Law of Conservation of Mass. Law of Conservation of Mass: This law states that: During a chemical reaction, the total mass of the reactants equals the total mass of the products. The total mass remains constant during a chemical change. Example: Mercury + Oxygen = Mercury (II) oxide (red-orange residue) mass of reactants = mass of products (According to the Law of Conservation of mass)