Chemistry Lesson 1 - Fundamentals of Chemistry PDF

CHEMISTRY FDN 1205 BASIC SCIENCE FOR NON-SCIENCE STUDENTS https://www.yu.edu/stern/ug/chemistry-biochemistry Reference  What is Chemistry, and What Can Chemistry Do for You? You may...

CHEMISTRY FDN 1205 BASIC SCIENCE FOR NON-SCIENCE STUDENTS https://www.yu.edu/stern/ug/chemistry-biochemistry Reference  What is Chemistry, and What Can Chemistry Do for You? You may wonder why Why the boiling water bubbles and produces steam while the teakettle retains its original shape? freegreatpicture.com How do the tea leaves change the color of the water while the teabag remains as full and plump as ever? Why does sugar make your tea sweet, and why is the tea itself bitter? How gasoline burns and drives vehicles down the road? How does it pollute the air we breathe? Dreamstime.com Why some books that are hundreds of years old are still in good shape while other books that are only 50 years old have pages that are brown, brittle, and crumbling. Can the books with damaged pages be saved? Chemists can answer all these questions Mrgranato.wordpress.com Others like them  Some Fundamental Definitions The science of chemistry deals with the makeup of the entire physical universe. Matter is the “stuff” of the universe: air, glass, planets, students—anything that has mass and volume. All matter is composed of tiny particles. These particles are in constant motion. The amount of motion is related to temperature. Solids, gases, and liquids differ in the freedom of motion of their particles and in how strongly the particles attract each other. Gas Liquid Solid Siyavula.com Chemistry is the study of matter and its properties, the changes that matter undergoes, and the energy associated with those changes.  Solids We can imagine particles of a solid as spheres which are held closely together by strong attractions among themselves. Solid However all the particles are in motion, bumping and pulling one another. Because they are so crowded and exert strong mutual attractions, these particles exhibit limited mobility. (Imagine yourself riding on one of the particle in above picture. You will have to face to large number of accidents (collisions) and your direction and the speed may vary due to the collisions.) When a solid is heated, speed of the moving particles increases. Faster particles colloid more violently causing each particles to push farther away. Therefore increased temperature causes solid to expand to some extent. Eg: Railway lines are laid with small gaps to allow for the expansion. Pwayblog.com  Liquids Particles in a liquid are still close together, but there is more empty space between them than in a solid. Liquid Therefore, when a solid substance melts to form a liquid, it usually expands to fill a slightly larger volume. In a liquid the particles are moving faster and there is more empty space between them, the attractions are easily broken and reformed, and the particles change location freely. This freedom of movement allows liquids to flow, taking on the shape of their container. chemistryworld.com  Gases The particles of a gas are much farther apart than in a solid or liquid. Therefore there is no significant attraction between them. In the air around us, for example, gas particles themselves taking up only about 0.1% of the total volume. The other 99.9% of the total volume is empty space. In contrast, the particles of a liquid fill about 70% of the liquid’s total volume. Gas Liquid Solid Each particle in a gas moves freely in a straight-line path until it collides with another gas particle. The particles are usually moving fast enough to break any attraction that might form between them, so after two particles collide, they bounce off each other and continue on their way alone. Have you ever noticed when the petrol or kerosene (as you know they are liquids)is spilled, how quickly the smell find your nose. How can you explain this?  Some Fundamental Definitions Matter Matter can be classified into three types based on its composition elements compounds mixtures An element is the simplest type of matter. A compound is a type of matter composed of two or more It has unique physical and chemical different elements that are chemically bound together. properties. Its properties are different from those of its component elements. An element consists of only one kind of A given compounds has a fixed composition. Therefore we can atom. Therefore the composition is fixed. call it a substance. It cannot be broken down into a simpler Eg: water: H2O, glucose: C6H12O6 type of matter by any physical or chemical methods. A mixture is a group of two or more substances (elements Each element has a name, such as silicon, and/or compounds) that are physically bound together. oxygen, aluminum, carbon or copper. Its composition is not fixed; a mixture is not a substance. Eg: sea water (salt and water), Sciencenotes.org milk tea (milk, sugar, tea, and water) gunpowder (Potassium nitrate, sulfur, and carbon)  Some Fundamental Definitions Atom: If you divide an element into smaller particles, the smallest unit you get is called an atom. Properties of an atom Spherical in shape, composed of a center and a surrounding. Center (we call it “nucleus”) is positively charged, surrounding is negatively charged, however net charge of an atom is zero (neutral). Nucleus consist of neutrons and protons. Neutrons are neutral and protons are positively charged. Protons are responsible for the positive charge of the nucleus. Surrounding consists of electrons which carry negative charge. An atom is neutral because the number of protons in the nucleus equals the number of electrons surrounding the nucleus. (positive charges and negative charges cancelling off) Pngitem.com  Some Fundamental Definitions Electrons move rapidly around the nucleus however they held by the attraction of the nucleus. Nucleus is incredibly dense (responsible for the 99.97% of the atom’s mass. Hydrogen (H) atom Carbon (C) atom H is the smallest atom. quora.com pinterest.com H contains C contains a single positively charged proton in the nucleus 6 positively charged proton in the nucleus and and a single negatively charged electron bound to the nucleus. 6 negatively charged electron bound to the nucleus. and and no neutrons 6 neutrons  Some Fundamental Definitions Atomic number = number of protons in the nucleus Mass number = total number of protons and neutrons Number of neutrons = mass number – atomic number Every element has an atomic symbol based on above numbers called atomic symbol.  Some Fundamental Definitions As mentioned earlier an element is composed of same type of atoms. All atoms of an element have same atomic number. However mass number may differ. In other words they have different number of neutrons. Atoms that have different neutrons/ different mass number are called Isotopes For example, all carbon atoms have 6 protons and 6 electrons. However only 98.89% of naturally occurring carbon atoms have 6 neutrons in the nucleus. A small percentage (1.11%) have 7 neutrons in the nucleus and even fewer (less than 0.01%) have 8 neutrons. experiment.com There are three naturally occurring carbon’s isotopes — 12C, 13C, and 14C. And five other carbon isotopes—9C, 10C, 11C, 15C, and 16C—have been created in the laboratory. all isotopes of an element have nearly identical chemical behavior, even though they have different masses