Understanding Pure Substances, Mixtures, and Chemical Reactions

SNC2D1 Grade 10 Science Chemistry Test Pure Substances and Mixtures Pure substance: any matter made up of one type of element/atom Element/compounds: symbols, cannot break down/formulas broken down from molecules Mixture: any matter that is made up of more than one type of atom Homogeneous/Heterogeneous: 1 part/many parts Properties Physical: Change of state Change in shape Reversible Dissolving Chemical: Change of colour Release of gas Hard to reverse Release of heat Precipitate Ions: -Elements which have gained or lost electrons to make their outer orbital’s filled -Net charge of 0, indicated by a + or -, depending on amount of extra electron -CATION = + -ANION = – -Based on their column on the periodic table and the amount of valence electrons, they will make bonds with each other… Add up to 8 -Electrons move from one atom to another to make it full -When a substance is dissolved in water, it separates into ions, creating a solution that conducts electricity. Ionic Compounds Naming -metal followed by the nonmetals +ide. -Transitional metals need (XX) to indicate its charge -Criss Cross method for formulas Polyatomic compounds -an ion made up of more than one atoms that acts as a single particle Naming/formula -write the name of the cation, then the ide after the anion -criss cross to determine the charges Molecular compounds/covalent compounds -compounds that bond together by sharing electrons not by giving them away -some contain diatomic particles that always come in a pair of two –HOFBrINCl -Naming uses a set of some common molecular names -Second term/first that is more than 1 will use prefix system -no charges Reactants and product -Chemical reactants come together and react to form a product Decomposition -single compound breaks down into other elements/compounds AB -> A +B Synthesis -Opposite to decomp A+B -> AB Single Displacement -one element replaces another in a compound, leaving an element alone A+BC -> AC+B Double Displacement -elements in two compounds switch places with others in the formula AB+CD -> AD+CB -Combustion -rapid reaction with oxygen to create oxides -fuel + oxygen -> oxides + energy Hydrocarbons -hydrocarbons + oxygen -> carbon dioxide + water Incomplete combustion -releases CO, CO2, H2O, and C -happens when there aren’t enough oxygen Oxidation -metals reaction with oxides in a slow process to produce an oxide on a surface Law of conservation of mass -the mass of the reactant will equal the mass of the product -means that we have to balance equations to have them equal and work with the law -using coefficients and multipliers Word equations -use -> to separate reactant and product -use naming from before Skeleton equations -equations that look at a reaction simply based on what they are… unedited Balanced equations -equations that look at reactions with edited, balancing them on both sides by adding coefficients Count atoms -Look at subscript and multiply obeying with brackets and coefficients Corrosion -Bad: car rusting -Good: ?? someone add that -Preventing corrosion: forgot what odlum said… ADD! Acids: -Acids: reacts with metals, carbonates -Neutralizes bases and vice versa -Conducts electricity because it has ions in it -reacts with metals to create H2 -reacts with carbonates to create CO2 -reacts with water to create hydrogen -all acids have “hydro” in front -hydrofluoric, hydrochloric… -used to be preservatives and add to food for tastes -Oxyacids derive from polyatomic ions containing oxygen and hydrogen. -basically (add onto it) a –ate polyatomic ion that has H2 in it to be an acid -Acetic, Nitric, Carbonic -turns blue litmus paper pink and keeps pink litmus paper pink Bases: -When dissolved in water, it gives off a OH ion -turns red litmus paper to blue and keeps blue litmus paper blue -neutralizes acids -used as cleaners, neutralize acids, clean drains Sodium Hydroxide, calcium hydroxide etc. pH -the level of how acidic or basic a solution is -“power of hydrogen” -acids: H+ -bases: OH-Range from 0-7-14 -7 is water, neutral -1 is acetic -14 is basic -6-7 and 7-8 are considered slightly acidic or basic Logarithms -the Log10 of a # is the power that 10 must be taken to equal to that number pH=-log10[H+] pH: negative log of the hydrogen ion concentration -Adding of base or acid can help adjust the pH -when acids and bases are mixed, the resultant solution is between that of the acid and base -each whole integer pH scale is multiplied by 10X Neutralization Reaction -Acids + bases -> a salt+water -hydrochloric acid + sodium hydroxide -> salt + water -used to reduce acids in soil to prevent them from being in the lake