Page 1:

• Pure substances are classified as either elements or compounds.

• An element is composed of only one type of atom.

• The six most abundant elements in our body account for 99% of our mass.

Page 2:

• Oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus are important elements in the body.

• Each element has a specific function and percentage by mass in the body.

Page 3:

• A compound is composed of two or more elements combined chemically in definite proportions.

• The particles in a compound are held together by a chemical bond.

Page 4:

• A compound can only be decomposed into its elements by chemical means.

• The properties of a compound are different from the properties of the elements it is composed of.

Page 5:

• Mixtures are made up of two or more substances physically combined.

• Mixtures can be separated into their components by simple physical means.

Page 6:

• Mixtures can be either heterogeneous or homogeneous.

• Homogeneous mixtures have a uniform appearance and composition throughout the sample.

Page 7:

• A solution is a homogeneous mixture of two or more substances.

• Solutions consist of a solute (what gets dissolved) and a solvent (the dispersing medium).

Page 8:

• Heterogeneous mixtures have components that can be physically identified or distinguished.

• The parts of a heterogeneous mixture are not evenly distributed in the sample.

Page 10:

• The earliest belief about matter was that it was made up of a single element.

• Empedocles proposed that all matter is made up of four fundamental elements.

Page 11:

• Empedocles introduced the law of constant proportions.

• Leucippus and Democritus proposed the concept of atoms, which are indivisible units.

Page 15:

• Matter exists in three main phases: solid, liquid, and gas.

• Solids have a definite shape and volume, with tightly packed particles.

Page 16:

• Liquids have no definite shape but have a definite volume.

• The particles in a liquid can move past each other, allowing the liquid to flow.

Page 17:

• Gases take the shape and volume of their container.

• The particles of gases are far apart and can be easily compressed.

Page 19:

• Plasma is the fourth state of matter, consisting of charged particles.

• Plasma has no definite shape or volume and is often observed in ionized gases.

Page 20:

• Bose-Einstein Condensate (BEC) is a state of matter where bosons condense at very low temperatures.

• BEC is observed in superfluids and superconductors.

Page 21:

• Physical properties of matter can be observed without changing the composition of a substance.

• Examples of physical properties include melting point, boiling point, color, and density.

Page 24:

• Chemical properties of matter can be observed with a change in the chemical composition of a substance.

• Chemical reactivity is a property that describes how a substance reacts with another substance.

Page 25:

• Extensive properties depend on the amount of matter, such as mass and volume.

• Intensive properties can be used to distinguish a specific substance from others, such as density and color.

Page 27:

• Filtration is a physical method of separating mixtures where fluids pass through a filter or filtering medium.

Page 28: Physical Methods of Separating Mixtures - Centrifugation

• Centrifuges rotate containers of liquids to separate suspended materials with different densities.

• Centrifuges are used to separate different components of human blood or milk and to clarify solutions.

Page 29: Physical Methods of Separating Mixtures - Decantation

• Decantation is used to separate a mixture of liquid and a heavy insoluble solid like soil or starch.

• The solid settles to the bottom of the container, and the liquid above the solid can be poured off carefully into another container.

Page 30: Physical Methods of Separating Mixtures - Evaporation

• Evaporation is a process where a liquid changes state from a liquid to a gas.

• Evaporation occurs only from the surface of the liquid.

Page 32: Physical Methods of Separating Mixtures - Distillation

• Distillation is a method used to separate a liquid from a solution through boiling and condensation.

Page 34: Physical Methods of Separating Mixtures - Chromatography

• Chromatography is a method used to separate small amounts of chemicals for analysis.

• Different substances or different components move at different speeds through a strip of wet paper.

Page 37: Accuracy and Precision

• The three measured values are the numerical quantity, the unit, and the name of the substance or material.

• Precision defines the closeness of measurements within a set of data to one another.

• Accuracy is a measure of how close a measurement is to the true or accepted value.

Page 38: Scientific Notation

• Scientific notation is a simple way to write and keep track of very large or very small numbers without having to deal with a lot of zeros.

• For numbers larger than 10, the decimal point must be moved to the left, so the exponent is a positive number.

• Example: 602,220 = 6.022 x 10^5

Page 42: Scientific Notation Operations - Multiplication/Division

• In multiplication, the numerical parts are simply multiplied and the exponents are added.

• In division, the numbers are divided and the exponents are subtracted algebraically.

Page 43: Significant Figures

• Significant figures or significant digits refer to the certain digits and the estimated digit of a measurement.

• Any digit that is not zero is significant.

• Leading zeros are never significant.

• Zeros in between significant digits are always significant.

• Trailing zeros are significant only if the decimal point is identified or specified.

Page 50: Measurements and Sources of Errors - Mass and Weight

• Mass is the amount of matter in the body and is fixed and unvarying.

• Weight is the measure of the Earth's gravitational attraction for that body and varies in relation to the position of an object.

Page 51: Measurements and Sources of Errors - Weighing Balances

• The mass of an object may be measured using weighing balances.

• Triple beam balance is accurate to one decimal place, top loading balance is accurate up to two decimal places, and an analytical balance is accurate up to four decimal places.

Page 52:

• Volume is the amount of space occupied by an object.

• The interface of a liquid in any container is usually curved, the curvature is called meniscus and is observed to measure a liquid's volume.

Page 53:

• If the object is solid, measure its length (L), width (W), and height (H) and calculate the volume using the formula: L x W x H.

• If the object is irregularly shaped, volume can be measured using the displacement method.

Page 54:

• Density is defined as the mass per unit volume of a material.

• Densities of objects are reported in g/mL or g/cm3 (for solids and liquids) or g/L (for gases).

• Substances have different densities, such as oxygen, sugar, salt, iron, copper, lead, mercury, gold, human fat, earth, and water.

Page 55:

• Sample problems involving density calculations:

  • Finding the density of a statue with given mass and volume.

  • Finding the volume of liquid mercury with given mass and density.

  • Finding the mass of a solution with given density and volume.

  • Calculating the density of a liquid in a beaker with given mass and volume.

  • Calculating the density of a rectangular block with given mass and dimensions.

Page 57:

• The emergence of chemistry as a discipline began with Robert Boyle's work "The Sceptical Chymist".

• Joseph Priestly isolated oxygen gas, leading to a breakthrough in the concept of elements and compounds.

Page 58:

• Antoine Lavoisier carried out experiments with oxygen and discovered and named hydrogen.

• The Law of Conservation of Mass was formulated in 1774.

Page 59:

• The Law of Conservation of Mass is the foundation for stoichiometric calculations in chemical reactions.

Page 60:

• Joseph Proust established the Law of Definite Proportions, stating that any sample of a given compound will always be composed of the same elements in the same proportions by mass.

Page 61:

• John Dalton proposed the Law of Multiple Proportions, which states that for elements that can form different compounds between them, the masses of the second element that can combine with a fixed mass of the first element are in a ratio of small whole numbers.

Page 63:

• Dalton's Atomic Theory:

  • Matter is made of extremely small indivisible particles called atoms.

Page 64:

• Atoms of the same element are identical and are different from the atoms of other elements.

Page 65:

• Compounds are formed when atoms of different elements combine in certain whole-number ratios.

Page 66:

• Atoms rearrange only during a chemical reaction to form new compounds.

Page 67:

• Electrons were discovered by JJ Thomson in 1897 through his observations of cathode rays in an evacuated tube.

• Thomson proposed the "plum-pudding" model for the atom.

Page 68:

• Robert Millikan determined the actual charge of the electron through his "oil drop experiment" in 1910.

Page 69:

• Ernest Rutherford discovered alpha and beta rays through the discovery of X-ray and radioactivity.

• Rutherford performed the "gold foil experiment" in 1909, leading to the discovery of the nucleus and his Nuclear model of the atom.

• Rutherford also discovered the proton in 1920.

Page 71:

• James Chadwick discovered the neutron, another sub-atomic particle in the nucleus.

Page 72:

• Subatomic particles:

  • Electron: symbol e-, mass: 9.110x10-28 gram, charge: -1.602x10-19 coulomb.

  • Proton: symbol p, mass: 1.673x10-24 gram, charge: 1.602x10-19 coulomb.

  • Neutron: symbol n, mass: 1.675x10-24 gram, charge: 0.

Page 73:

• Atomic number (Z) represents the count of the number of protons in an atom.

• Mass number (A) counts the number of protons and neutrons in an atom.

Page 75:

• Henry Moseley discovered the relation between the x-ray spectra of certain elements and their atomic number, leading to the association of the atomic number with the number of protons in the nucleus.

Page 76:

• Isotopes are atoms with the same number of protons but different numbers of neutrons.

• Atoms of the same element can have different mass numbers.

Page 78:

• When a neutral atom gains or loses one or more electrons, it becomes an electrically charged particle called an ion.

• Metals tend to lose electrons and become positively charged cations.

• Nonmetals gain electrons and become negatively charged anions.

Page 79:

• Monoatomic ions consist of only one atom.

• Different atoms can combine to form polyatomic ions.