002.Matter-and-Atoms.pdf

Colegio San Agustin – Bacolod College of Health and Allied Professions Matter and Atoms Engr. Socorro E. Mamar Chemistry and Matter Chemistry is the science that deals with matter: the structure and properties of matter and the transformations from one form of matter to another,...

Colegio San Agustin – Bacolod College of Health and Allied Professions Matter and Atoms Engr. Socorro E. Mamar Chemistry and Matter Chemistry is the science that deals with matter: the structure and properties of matter and the transformations from one form of matter to another, including the energy involved during such changes CHEM 101M: Inorganic and Organic Chemistry MATTER, PROPERTIES,CHANGES, ENERGY MATTER- anything that occupies space and has mass Mass- quantity of matter present in a body Weight- force or pull of gravity acting on an object Properties-distinctive attributes or characteristics by which a given substance can be identified Changes – the transformation of matter which may either physical or chemical Energy - the ability of the body to cause changes or the ability to do work Chemistry and Matter CHEM 101M: Inorganic and Organic Chemistry States of Matter A gas (also known as vapor) has no fixed volume or shape; rather, it uniformly fills its container. A gas can be compressed to occupy a smaller volume, or it can expand to occupy a larger one. A liquid has a distinct volume independent of its container, assumes the shape of the portion of the container it occupies, and is not compressible to any appreciable extent. A solid has both a definite shape and a definite volume and is not compressible to any appreciable extent. CHEM 101M: Inorganic and Organic Chemistry States of Matter CHEM 101M: Inorganic and Organic Chemistry Pure Substances A pure substance (usually referred to simply as a substance) is matter that has distinct properties and a composition that does not vary from sample to sample. All substances are either elements or compounds. CHEM 101M: Inorganic and Organic Chemistry Elements Elements are substances that cannot be decomposed into simpler substances. On the molecular level, each element is composed of only one kind of atom. Currently, 118 elements are known. Of these, 98 occur in nature; chemists and physicists have made the others in the laboratory. CHEM 101M: Inorganic and Organic Chemistry Elements CHEM 101M: Inorganic and Organic Chemistry Elements CHEM 101M: Inorganic and Organic Chemistry Elements Ca Strengthens bones and teeth; C, H, O, N aids blood clotting. The big four. Mg Components of Helps nerve and Organic muscle action; Compounds found in the present in bones. human body. Cl Necessary for normal growth and Development. CHEM 101M: Inorganic and Organic Chemistry  P Present as S phosphates in bone, in An essential nucleic acids (DNA component of K and RNA), proteins. and involved in Helps regulate energy storage and electrical balance transfer. in body fluids; essential for nerve conduction. Deficiency may cause muscle weakness, paralysis CHEM 101M: Inorganic and Organic Chemistry  Na Cu Helps regulate Strengthens electrical balance bones; assists in in body fluids. enzyme activity. Deficiency may Deficiency may cause muscle , cause anemia, apathy, reduced Co fragility ofarteries, appetite Part of vitamin inhibitd growth B-12 (Cobalamin). Deficiency may cause pernicious anemia Cr F Increase Reduces the effectiveness of incidence of insulin. dental cavities. CHEM 101M: Inorganic and Organic Chemistry  Fe An essential part of I some proteins, such as hemoglobin, An essential part of myoglobin, thyroid hormones. cytochromes, and FeS proteins. Mo Helps regulate electrical balance in Zn body fluids Mn Necessary for the action of certain Present in enzymes. bone-forming Deficiency may enzymes; aids in fat cause poor growth, and carbohydrate lack of sexual metabolism maturation, abnormal glucose tolerance CHEM 101M: Inorganic and Organic Chemistry Compounds A compound is a pure substance made up of two or more elements in a fixed ratio by mass. Most elements can interact with other elements to form compounds. For example, when hydrogen gas burns in oxygen gas, the elements hydrogen and oxygen combine to form the compound water. CHEM 101M: Inorganic and Organic Chemistry Compounds A compound is characterized by its formula. The formula gives us the ratios of the compound’s constituent elements and identifies each element by its atomic symbol. CHEM 101M: Inorganic and Organic Chemistry Mixtures Each substance in a mixture retains its chemical identity and properties. In contrast to a pure substance, which has a fixed composition, the composition of a mixture can vary. The substances making up a mixture are called components of the mixture. CHEM 101M: Inorganic and Organic Chemistry Mixtures Mixtures that do not have the same composition, properties, and appearance throughout are called heterogenous. Mixtures that are uniform throughout are homogeneous. Homogeneous mixtures are also called solutions. CHEM 101M: Inorganic and Organic Chemistry Classification of Matter CHEM 101M: Inorganic and Organic Chemistry Changes in Matter The changes substances undergo are either physical or chemical. During a physical change, a substance changes its physical appearance but not its composition. That is, it is the same substance before and after the change. All changes of state (for example, from liquid to gas or from liquid to solid) are physical changes. CHEM 101M: Inorganic and Organic Chemistry Changes in Matter In a chemical change (also called a chemical reaction), a substance is transformed into a chemically different substance. CHEM 101M: Inorganic and Organic Chemistry Atomic Theory Atoms are the smallest particle of an element that retains the chemical properties of the element. In 1808 the English chemist John Dalton put forth a model of matter that underlies modern scientific atomic theory: All matter is made up of very tiny, indivisible particles, which Dalton called atoms. All atoms of a given element have the same chemical properties. Conversely, atoms of different elements have different chemical properties. CHEM 101M: Inorganic and Organic Chemistry Atomic Theory In ordinary chemical reactions, no atom of any element disappears or is changed into an atom of another element. Compounds are formed by the chemical combination of two or more different kinds of atoms. A molecule is a tightly bound combination of two or more atoms that acts as a single unit. CHEM 101M: Inorganic and Organic Chemistry Law of Conservation of Mass French chemist Antoine Laurent Lavoisier (1743– 1794) discovered the law of conservation of mass, which states that matter can neither be created nor destroyed. Dalton’s theory explained this fact in the following way: If all matter consists of indestructible atoms (postulate 1) and if no atoms of any element disappear or are changed into an atom of a different element (postulate 3), then any chemical reaction simply changes the attachments between atoms but does not destroy the atoms themselves. CHEM 101M: Inorganic and Organic Chemistry Law of Conservation of Mass CHEM 101M: Inorganic and Organic Chemistry Law of Constant Composition A French chemist, Joseph Proust, demonstrated the law of constant composition, which states that any compound is always made up of elements in the same proportion by mass. If the atomic ratio of the elements in a compound is fixed (postulate 4), then their proportions by mass must also be fixed. CHEM 101M: Inorganic and Organic Chemistry Monatomic and Diatomic Monatomic elements consist of single atoms that are not connected to each other. Example are helium and neon. Diatomic Elements contains two atoms in each molecule, connected to each other by a chemical bond. Seven elements occur as diatomic molecules (that is, they contain two atoms of the same element per molecule): oxygen (O2), hydrogen (H2), nitrogen (N2), fluorine (F2), chlorine (Cl2), bromine (Br2), and iodine (I2). CHEM 101M: Inorganic and Organic Chemistry Subatomic Particles Three subatomic particles make up all atoms: protons, electrons, and neutrons. Proton is a subatomic particle with a charge of +1 and a mass of approximately 1 amu; it is found in a nucleus. Electron is a subatomic particle with a charge of -1 and a mass of approximately 0.0005 amu. It is found in the space surrounding a nucleus. Neutron is a subatomic particle with a mass of approximately 1 amu and a charge of zero; it is found in the nucleus. Atomic mass unit (amu) is a unit of the scale of relative masses of atoms. CHEM 101M: Inorganic and Organic Chemistry Subatomic Particles CHEM 101M: Inorganic and Organic Chemistry Mass Number Mass number (A) is the sum of the number of protons and neutrons in its nucleus. Note that an atom also contains electrons, but because the mass of an electron is so small compared to that of protons and neutrons, electrons are not counted in determining mass number. CHEM 101M: Inorganic and Organic Chemistry Atomic Number The atomic number (Z) of an element is the number of protons in its nucleus. Note that in a neutral atom, the number of electrons is equal to the number of protons. Atomic numbers for all the known elements are given in the Periodic Table of Elements. CHEM 101M: Inorganic and Organic Chemistry Isotopes Atoms with the same number of protons but different numbers of neutrons are called isotopes. Most of the carbon atoms found in nature have 6 neutrons; the mass number of these atoms is 12, they are written as carbon‑ -12. Other carbon atoms have 6 protons and 7 neutrons and, therefore, a l,are written as carbon‑ -13. Still other carbon atoms have 6 protons and 8 neutrons; they are written as carbon‑ -14. CHEM 101M: Inorganic and Organic Chemistry Example How many protons, neutrons, and electrons are in (a) an atom of 197Au, (b) an atom of strontium-90? CHEM 101M: Inorganic and Organic Chemistry Example How many protons, neutrons, and electrons are in (a) an atom of 197Au, (b) an atom of strontium-90? CHEM 101M: Inorganic and Organic Chemistry Example How many neutrons are in each isotope of oxygen? (a) Oxygen-16 (b) Oxygen-17 (c) Oxygen-18 CHEM 101M: Inorganic and Organic Chemistry