Chemical Reactions Richard Guo

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Chemical Reactions Richard Guo により Mind Map: Chemical Reactions Richard Guo

1. 8. Oxy Acids Oxy acids are polyatomic ions with varying amounts of oxygen bound to hydrogen ion(s) (ex. NO3^- + H → HNO3 (aq)) The oxy acid’s name changes depending on the amount of oxygen in the polyatomic ion

1.1. When the polyatomic ion has an extra oxygen ion, the name changes to per__ic acid (ex. HNO4 (aq) --》 pernitric acid) When the polyatomic ion has not gained/lost an oxygen ion, the name becomes __ic acid (ex. HNO3 (aq) → nitric acid) When the polyatomic ion has one less oxygen ion, the name becomes __ous acid (ex. HNO2 (aq) → nitrous acid) When the polyatomic ion has 2 less oxygen ions, the name becomes hypo__ous acid (HNO (sq) → hyponitrous acid)

1.1.1. Formula: As always, switch the charge of the polyatomic ion to the hydrogen (the charge doesn’t change even when it gains/loses oxygen ions)

2. Balancing Chemical Equations

2.1. Due to the switch of charges ionic compounds, molecular compounds, acids, bases, etc., the number of products may be unequal to the number of reactants. There are also diatomic elements, which exist in pairs when they are by themselves, but not when they are part of a compound, causing the number of such elements to be uneven among the reactants and products.

2.2. The law of conservation of mass states that “for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as system's mass cannot change, so quantity can neither be added nor be removed.” Therefore, the amount of reactants has to be equal to the amount of products. To balance the reactants and products, coefficients are needed.

2.3. To balance equations, the MINOH rule is a good way to start. First, try balancing the METALS, then the polyatomic IONS, then the NON-metals, the OXYGEN atoms, and finally the HYDROGEN atoms.

2.3.1. Unbalanced: H2 + O2 --> H2O Balanced: 2H2 + O2 --> 2H2O2 The reason why this equation isn't balanced is because of the HOFBrINCl diatomic elements, see "Balancing Chemical Equations" for more

3. Nomenclature

3.1. 1. Simple Binary Ionic Occurs when a metal and non metal bond

3.1.1. Write the symbols Write the charges Switch the charges Reduce Naming: Metal first, non metal second, change the non metal suffixe to -ide Ex. Mg2+ + S2- ----> MgS (Magnesium sulfide) All types of compounds will use the "Switch the charges" rule

3.2. 2. Multiple Valences - Stock System Occurs when a transition metal with more than 1 possible valence bonds with a non metal Ex. of a transition metal with more than 1 possible valence: Fe2+, Fe3+

3.2.1. When writing, use roman numerals to showcase the number of valences Change non metal suffixe to -ide Switch charges Ex. Fe (III) + O^2+ -----> Fe2O3 (Iron (III) oxide)

3.3. 3. Multiple Valences - Latin Prefixes *LIMITED TO MULTI VALENCES OF 2 ONLY* Uses a Latin prefix to determine the charge and transition metal

3.3.1. Antimony → Stib- Chromium → Chrom- Copper → Cupr- Iron → Ferr- Lead → Plumb- Tin → Stann- The suffix determines the charge on the transition metal “-ic” → larger valence number “-ous” → smaller valence number Ex. Fe (III) + O^2+ ---> Fe2O3 (ferric oxide)

3.4. 4. Polyatomic ionic Used when a metal reacts with a polyatomic ion (multiple ions made of more than one atom, but behave as a single ion)

3.4.1. Acronym: NICK the CAMEL ate a CLAM for SUPPER in PHOENIX (1st letter identifies the polyatomic in, # of vowels = valence, #consonants = oxygen atoms) BIG-5 polyatomic ions: NO3^- (nitrate), CO3^2- (carbonate), ClO3^- (chlorate), SO4^2- (sulfate), PO4^3- (phosphate) Irregular polyatomic ions: Acetate (C2H3O2^-), Cyanide (CN^-), Peroxide (O2^2-), Ammonium (NH4^+), Hydroxide (OH^-) NOTE: when the # of oxygen atoms in a BIG-5 polyatomic ion changes, it’s name changes as well (valence does not change) When a BIG-5 gains an oxygen atom, its name becomes per__ate (ex. ClO4^- perchlorate) When a BIG-5 has not gained/lost an oxygen atom, its name stays as __ate (ex. ClO3^- chlorate) When a BIG-5 loses an oxygen atom, its name becomes __ite (ex. ClO2^- chlorite) When a BIG-5 loses 2 oxygen atoms, its name becomes hypo__ite (ex. ClO^- hypochlorite) Formula Switch the charges Brackets around the polyatomic ion if the charge on the metal was >1

3.5. 5. Binary Compound with Hydrogen

3.5.1. If hydrogen has less EN than the binary compound, hydrogen comes first in the naming and formula (ex. HCl (H has less EN than Cl), hydrogen chloride) If hydrogen has more EN than the binary compound, hydrogen comes second in the naming and formula and its suffix changes to -ide (ex. NaH (H has more EN than Na), sodium hydride) Formula: As always, use the switch of charges and reduce

3.6. 6. Binary Acids (aq) Occurs when a non metal and hydrogen bond to form an acid

3.6.1. Formula Hydrogen always has a valence of 1, so the valence of the non metal switches to the hydrogen Must have subscript “(aq)” (ex. HCl (aq)) Naming Hydro__ic acid (ex. HCl (aq), hydrochloric acid)

3.6.2. Binary acids and bases will displace each other's cations to form an ionic compound and H2O in a neutralisation reaction. See "Types of Reactions --> Neutralisation" for more

3.7. 7. Bases Bases are substances that release hydroxide ions when placed in aqueous solutions

3.7.1. They are usually polyatomic ionic compounds, with hydroxide being the polyatomic ion bound to a metal (ex. Na(OH))

3.8. 9. Acid Salt Occurs when a polyatomic ion gains a positive hydrogen ion and decreases the net charge by 1 for every hydrogen ion added (ex. CO3^2- + H^+ → HCO3^- (notice how the 2- charge becomes 1- after gaining a hydrogen)

3.8.1. For naming, just name “hydrogen” before the polyatomic ion (ex. HCO3^-, hydrogen carbonate). Note: If more hydrogen ions have been added to further decrease the charge, uses molecular prefixes on hydrogen to indicate how many hydrogen ions are present in the acid salt. Examples: HCO3^- hydrogen carbonate, HPO4^2- hydrogen phosphate, H2PO4^- dihydrogen phosphate

3.9. 10. Covalent/Molecular Occurs when two non metals bond together

3.9.1. For covalent/molecular bonds, when you switch the charges, you do not reduce Prefixes are used to determine how much of each non metal is present in the bond

3.10. 11. Peroxides Occurs when a bond has one more oxygen ion than it should (ex. H2O is the regular dihydrogen monoxide and H2O2 is dihydrogen peroxide)

3.10.1. Do not reduce when there is a peroxide

3.10.2. A man walks into a bar and asks for an H2O. A second man walks into the same bar and asks for some H2O too. The second man dies of poison. Why? (Hint: H2O too)

3.11. 12. Additional Acids and Radicals

3.11.1. OCN^-, cyanate MnO4^-, permanganate C2O4^2-, oxalate CrO4^2-, chromate Cr2O7^2-, dichromate AsO4^3-, arsenate AsO3^3-, arsenite

3.12. 1-mono * mono only applies to the second element 2-di 3-tri 4-tetra 5-penta 6-hexa 7-hepta 8-octa 9-nona 10-deca

3.12.1. Examples: H2O dihydrogen monoxide, CO2 carbon dioxide

3.12.2. These prefixes are also used in acid salts when there is more than one postitive hydrogen ion. See "Nomenclature --> Acid Salt" for more

3.13. 13. Compounds when S replaces O

3.13.1. When S replaces O use the prefix Thio eg. H2SO4 sulphuric acid becomes H2S2O3 (thiosulphuric acid)

4. Types of reactions

4.1. Synthesis reaction

4.1.1. A synthesis reaction occurs when two compounds or elements combine to form a new compound. An example of a balanced synthesis reaction is 2H2 (g) + O2 (g) → 2H2O (l) When one of the reactants of a synthesis reaction is water (H2O), the product will be either an acid or a base, depending on the other reactant. If the other reactant is a non-metal oxide, such as Bromium dioxide (BrO2), the product will be an acid (BrO2 (g) + H2O (l) → H2BrO3 (aq)) If the other reactant is a metal oxide, such as beryllium oxide (BeO), the product will be a base (BeO (s) + H2O (l) → Be(OH)2 (aq))

4.2. Decomposition reaction

4.2.1. A decomposition reaction is the opposite of a synthesis reaction, and occurs when a compound breaks down into different elements or compounds. An example of a balanced decomposition reaction is 2H2O (l) → 2H2 (g) + O2 (g).

4.3. Combustion reaction

4.3.1. Combustion reactions can either be complete or incomplete and occur when a fuel reacts with oxygen to form oxides, water, and possibly carbon. A complete combustion occurs when there is enough oxygen in the reactants to react with the fuel and form both water vapor AND carbon dioxide. An example of a balanced complete combustion reaction is CH4 (g) + 2O2 (g) (energy) → CO2 (g) + 2H2O (g) An incomplete combustion occurs when there is not enough oxygen in the reactants and produces carbon monoxide, water vapor, and other products, such as solid carbon. An example of a balanced incomplete combustion reaction is 2C3H8 (g) + 7O2 (g) (energy) → 2C (s) + 2CO (g) + 2CO2 (g) + 8H2O (g) There are also instances where there is no carbon in a combustion reaction. These are called combustions of non-hydrocarbons. These occur when there is no carbon in the fuel and when they combust, they form stable oxides. An example of a balanced non-hydrocarbon combustion is S (s) + O2 (g) → SO2 (g)

4.4. Single displacement reactions

4.4.1. Single displacement reactions occur once one element in a compound is displaced by a second, different element. Single displacement reactions usually occur between metals and halogens, where a more reactive metal will displace a less reactive metal. However, a halogen is also able to displace another halogen less reactive than itself. Metal displacement example: Ca (s) + 2HCl (aq) → CaCl2 (aq) + H2 (g) Halogen displacement example: Cl2 (g) + 2LiBr (aq) → 2LiCl (aq) + Br2 (l)

4.5. Double displacement reactions

4.5.1. Neutralization reaction A neutralization reaction is a type of double displacement reaction that produces water. An acid and a base will displace each other’s cations to form an ionic compound and H2O

4.5.2. Double displacement reactions occur when two ionic compounds switch their cations (positive ions). The cations are always the metal, as metals lose electrons to become positive.

4.6. Note: All reactions must be balanced, see "Balancing Chemical Equations" for details