First Lecture Chemistry and Matter PDF

No Subject 1 Chemistry and Matter 2 The Measurements and Handling Numbers 3 Stoichiometry 4 Atomic Structure 5 Properties of Periodic Table 6 Chemical Bonds 7 Chemical Equilibrium 8 Thermochemistry 9 Introduction of Organic Chemistry ESSENTIAL CONCEPTS The...

No Subject 1 Chemistry and Matter 2 The Measurements and Handling Numbers 3 Stoichiometry 4 Atomic Structure 5 Properties of Periodic Table 6 Chemical Bonds 7 Chemical Equilibrium 8 Thermochemistry 9 Introduction of Organic Chemistry ESSENTIAL CONCEPTS The Study of Chemistry :Chemistry is the study of the properties of matter and the changes, it undergoes. Elements and compounds are substances that take part in chemical transformation. States of Matter Physical and Chemical Properties to Characterize a substance Measurements and Units Chemistry is a quantitative science The measured quantities (for example, mass, volume, density and temperature and requires measurements. i.e) usually have units associated with them. The units used in chemistry are based on the international system (SI) of units. Handling Numbers Scientific notation is used to express large and small numbers, and each number in a measurement must indicate digits, called significant figures. Chemistry is present in everything humans do and, in its body, growing and cooking food to cleaning homes chemistry helps humans understand what is going on around them in the world Chemistry: can be defined as the study of the composition, properties, and transformations of matter. In these lectures, we will examine some basic concepts in chemistry through which we can understand the language spoken by chemists, then we will examine the importance of chemistry for humanity and the extent of its interference in our lives.  Branches of Chemistry Organic Chemistry This branch deals with study of carbon compounds especially hydrocarbons and their derivatives. Inorganic Chemistry This branch deals with the study of compounds of all other elements except carbon and the study of minerals found in the Earth's crust.  Physical Chemistry: study of the physical and fundamental basis of chemical systems and processes. Important areas of study include chemical thermodynamics, kinetics, electrochemistry, statistical mechanics and spectroscopy,  Analytical Chemistry: This branch deals with the qualitative and quantitative analysis of substances.  Biochemistry: This branch deals with the chemical changes going on in the bodies of living organisms; plants and animals. The chemistry is the study of matter and the changes it undergoes. Matter is defined as anything that occupies space and has mass.  Classification of matter: All matter, can exist in three states: solid, liquid, and gas. Solids are rigid objects with definite shapes. Liquids are less rigid than solids and are fluid they can flow and assume the shape of their containers. Gases are fluid, but unlike liquids, they can expand indefinitely.  Conversion between three states Three states of matter can be interconverted without changing the composition of the substance. Upon heating, a solid (for example, ice) will melt to form a liquid (water). (The temperature at is called the melting point) Further heating will convert the liquid into a gas.(The boiling point) On the other hand, cooling a gas will cause it to condense into a liquid.   Matter can be classified as solid, liquid, or gas based on what properties it exhibits. State Shape Volume Compress Flow Solid Fixed Fixed No No Liquid Indef. Fixed No Yes Gas Indef. Indef. Yes Yes Fixed = Keeps shape when placed in a container. Indefinite = Takes the shape of the container.  Low density compared to solids and liquids.  Fluid.  Take the shape of their container(s).  Expand to fill their container(s).  Can be compressed into a smaller volume.  High density compared to gases.  Fluid.  Take the shape of their container(s).  Keep their volume, do not expand to fill their container(s).  Cannot be compressed into a smaller volume. 14  High density compared to gases.  Nonfluid.  Keep their own shape, do not take the shape of their container(s).  Keep their own volume, do not expand to fill their container(s).  Cannot be compressed into a smaller volume.  In the gas state, the particles have complete freedom from each other.  The particles are bumping into each other and their container(s).  In the gas state, there is a lot of empty space between the particles.  The particles in a liquid are closely packed, but they have some ability to move around.  The close packing results in liquids being incompressible.  But the ability of the particles to move allows liquids to take the shape of their container and to flow. However, they don’t have enough freedom to escape and expand to fill the container(s).  The particles in a solid are packed close together and are fixed in position.  The close packing of the particles results in solids being incompressible.  The inability of the particles to move around results in solids retaining their shape and volume when placed in a new container and prevents the particles from flowing.  Relative strength of attractive Phase Density Shape Volume forces Gas Low Indefinite Indefinite Weakest Liquid High Indefinite Definite Moderate Solid High Definite Definite Strongest  Generally, we convert a material in the solid state into a liquid by heating it.  Adding heat energy increases the amount of kinetic energy of the molecules in the solid.  Finally, they get enough energy to partially overcome the attractive forces holding them in place.  This allows the molecules enough extra freedom to move around a little and rotate.  Generally, we convert a material in the liquid state into a gas by heating it.  Adding heat energy increases the amount of kinetic energy of the molecules in the liquid.  Finally, they get enough energy to completely overcome the attractive forces holding them together.  This allows the molecules complete freedom to move around and rotate.  Qualitative and Quantitative Observations An important step in the scientific method is observation. In general, observations fall into two categories, qualitative and quantitative. Qualitative observations, such as the color of a chemical or that a mixture becomes hot when a reaction occurs, do not involve numerical information. Quantitative observations are those measurements that do yield numerical data.  Physical and Chemical Properties of Matter Substances are identified by their properties as well as by their composition. Color, melting point, boiling point, and density are physical properties. A physical property can be measured and observed without changing the composition. On the other hand, the statement “Hydrogen gas burns in oxygen gas to form water” describes a chemical property. After the change, the original substances, hydrogen and oxygen gas, will have vanished and a chemically different substance—water—will have taken their place. All measurable properties of matter fall into two categories: extensive properties and intensive properties. The measured value of an extensive property depends on how much matter is being considered. Mass, length, and volume are extensive properties. More matter means more mass. Values of the same extensive property can be added together. For example, the total volume occupied by the water in two beakers is the sum of the volumes of the water in each of the beakers. The measured value of an intensive property does not depend on the amount of matter being considered. Temperature is an intensive property. Suppose that we have two beakers of water at the same temperature. If we combine them to make a single quantity of water in a larger beaker, the temperature of the larger amount of water will be the same as it was in two separate beakers. temperature and other intensive properties such as melting point, boiling point. Substances and Mixtures A substance is matter that has a definite or constant composition Examples are water, silver, ethanol, table salt (sodium chloride), and carbon dioxide. Substances differ from one another in composition and can be identified by their appearance, smell, taste, and other properties. A mixture is a combination of two or more substances in which the substances retain their distinct identities. Some examples are air, soft drinks, milk, and cement. Mixtures do not have constant composition. Therefore, samples of air collected in different cities would probably differ in composition because of differences in altitude, pollution, and so on. Mixtures are either homogeneous or heterogeneous. Ex. Sugar Dissolves in water, This solution is a homogeneous mixture. If oil add to water Is called a heterogeneous mixture because the liquid does not have a constant composition. A compound as a substance composed of two or more elements chemically united in fixed proportions. Hydrogen gas, for example, burns in oxygen gas to form water, a compound whose properties are distinctly different from those of the starting materials. Water is made up of two parts of hydrogen and one part of oxygen.  Formation of a mixture of iron and sulfur. (a) Samples of powdered sulfur and powdered iron. (b) A mixture of sulfur and iron is made by stirring the two powders together. Formation of a mixture does not change chemical composition. Here we see that forming the mixture has not changed the iron and sulfur into a compound of these two elements. The mixture can be separated by pulling the iron out with a magnet. Making a mixture involves a physical change.  Elements and Compounds A substance can be either an element or a compound. An element is a substance that cannot be separated into simpler substances by chemical means.