Grade 9 AP Science Exam Review PDF

Chemistry States of Matter ○​ Change of State: change between solids, liquids and gases ○​ The particle theory of Matter: describes the structure of matter and the way it behaves Changes of State and Names 1.​ Melting: Solid to liquid 2.​ Freezing: Liquid to soli...

Chemistry States of Matter ○​ Change of State: change between solids, liquids and gases ○​ The particle theory of Matter: describes the structure of matter and the way it behaves Changes of State and Names 1.​ Melting: Solid to liquid 2.​ Freezing: Liquid to solid 3.​ Vaporization: Liquid to gas 4.​ Condensation: Gas to liquid 5.​ Sublimation: Solid to gas 6.​ Deposition: Gas to solid Physical and Chemical Properties Physical Properties: describes the physical appearance of a substance 1.​ Colour - the colour of the substance ex gold’s lustre and concrete dullness 2.​ Lustre - if shiny it reflects light, if dull no reflection 3.​ Conductivity - substance’s ability to conduct electricity or heat ex electric circuit wires to conduct electricity 4.​ Density - the amount of mass in a given volume ex fluids and solids with different densities 5.​ Ductility - solids that can be stretched into a long wire ex copper wire 6.​ Hardness - substance's ability to resist being scratched ex emerald gemstone 7.​ Malleability - substances that can be pounded or rolled into ex: aluminum foil  Viscosity - resistance of a fluid to flow ex maple syrup Chemical Properties: the ability of a substance to change into a new substance(s) 1.​ Absorbs heat in a reaction 2.​ Combustible 3.​ Forms gas when heated 4.​ Reacts with acid 5.​ Reacts with water 6.​ Emits Heat during a reaction 7.​ Emits light during a reaction 8.​ Forms a solid in solution Physical and Chemical Changes Physical Changes: no change to chemical composition Evidence of Physical change: ➔​ building and breaking- cutting up an apple ➔​ Dissolving- salt water to evaporate h2O ➔​ Change of state- solid to liquid to gas Chemical Changes: change in the chemical composition Evidence of Chemical change: ➔​ colour change ➔​ odour/taste change ➔​ heat change ➔​ gas formed ➔​ precipitate ➔​ new substance formed  ➔​ Not reversible Density Formulas ➔​ Density = mass ÷ volume, Mass = density × volume, Volume = mass ÷ density Density of a Solid and Irregular Solid​ 1.​ Regular Solid:​ Measure mass with a scale and volume using l × w × h 2.​ Irregular Solid:​ Use the displacement method: Measure mass with scale For volume ○​ Record the initial water level in a graduated cylinder. ○​ Place the object in water and record the new water level. ○​ Volume = Final water level - Initial water level. Bohr Diagrams ​ Definition: Bohr diagrams show the arrangement of electrons in an atom's energy levels around the nucleus. ○​ Nucleus: Write the number of protons (p) and neutrons (n) inside the nucleus. ○​ Electron Shells: Arrange electrons in shells (energy levels) around the nucleus: ​ 1st shell: 2 electrons. ​ 2nd shell: 8 electrons. ​ 3rd shell: 18 electrons The electrons in the outermost shell are called Valence electrons 5. Finding p, e, n and Identity ​ Definitions: ○​ p (Protons): Equal to the atomic number. ○​ e (Electrons): Equal to protons in a neutral atom. ○​ n (Neutrons): Neutrons = Mass number−Atomic number = Example for Oxygen (O): ○​ Atomic number = 8 (protons = 8, electrons = 8 for neutral atom). ○​ Mass number = 16 → Neutrons = 16 − 8 = 8 Properties of Metals, Nonmetals, and Metalloids 1.​ Metals: ○​ Shiny, high density, malleable/ductile, good conductors of heat/electricity ○​ Lustrous, usually solid at room temperature ○​ Examples: Ag, Na, Hg, Brass, Bronze, Al, Cast, Fe, Cu, Steel, Metalsludge 2.​ Nonmetals: ○​ Dull, low density, insulator, solid or gas or liquid, brittle (if solid) ○​ Can be solids, liquids, or gases at room temperature ○​ Examples: S (Solid), Br (liquids), 0 (gas) 3.​ Metalloids: ○​ Elements near the staircase that separates metals and non-metals ○​ Properties of both metals and nonmetals ○​ Semi-conductors ○​ Examples: Al and S Definitions 1.​ Atom: As found in the periodic table 2.​ Ion: has a charge (gain electrons→negative) ( lose an electron→positive you subtract) 3.​ Isotope: different mass than the periodic table 4.​ Ionic Isotope: has a change in the number of electrons and neutrons 5.​ Ionic Bond: A bond formed when electrons are transferred between atoms. 6.​ Atomic Mass: the sum of the protons and neutrons (Atomic mass - Atomic number = # of neutrons 7.​ Atomic Number: is the number of protons in an atom f) Importance of Valence Electrons ​ Valence electrons determine an atom’s chemical reactivity and bonding capacity. ​ Elements in the same periodic table group have the same number of valence electrons. Ionic and Molecular Compounds 1.​ Ionic Compounds: ○​ Has charges ○​ Non-metal and metals ○​ Electrons are transferred ○​ High melting point ○​ Solid crystal ○​ Good conductor of electricity dissolves in water Examples: Copper, Nickel, Lead, Iron, Tin, Silver, Gold, Zinc, Mercury  2.​ Molecular or Covalent Compounds: ○​ Has no charges ○​ Non- metal + non-metals ○​ Electrons are shared ○​ Low melting Point ○​ Solid, Liquid and Gas ○​ Good insulators ○​ Do not dissolve in water ○​ Positive and negative ions attract and form an ionic bond Examples: Water, Ammonia, Hydrogen Peroxide, Methane, Chlorine gas, Oxygen gas, Hydrogen Gas, Nitrogen gas Forming and Naming Ionic and Molecular Compounds 1.​ Ionic Compounds ○​ Ending in “ide” ○​ Crisscross ionic charge ○​ Reduce Roman numeral for transition metal 2.​ Molecular Compounds ○​ Uses prefixes (Mono, Di, Tri, Tetra, Penta) ○​ No reducing ○​ No roman numeral ○​ Ending in “ide” ○​ PS5 = phosphorus pentasulfide