Chemical Changes(mainly for memorisation, lower sec)

Chemical Formulas To Memorise 😪 Under Chapter: Chemical Changes. Memorise the acids, reactions and much more 🙄 MemoriseChemicals⚛ (a) Acids( noneed tomemorisetheuse) Name Of Acid Formula of Acid Use or application of acid Hydrochloric Acid HCl Found in Stomach – to digest food Nitric Acid HNO ₃ Make fertilisers and explosives Sulfuric Acid H ₂ SO ₄ Found in batteries of cars andlorries Phosphoric Acid H ₃ PO ₄ Used as food preservatives andflavouring in Coca-Cola Ethanoic Acid CH ₃ COOH Eg. of this acid: vinegar(dilutever.) (b) CommonPolyatomicIons Name Hydroxide Nitrate Sulfate carbonate Phosphate Formula OH ⁻ NO ₃⁻ SO ₄²⁻ CO ₃²⁻ PO ₄³⁻ Valency -1 -1 -2 -2 -3 (c) Others

Name Formula Ammonia NH ₃ Ammonium NH ₄ ⁺ Ammonium Salt NH ₄__ Carbonate CO ₃→if metal carbonate is__CO ₃ Nitride N ³ ⁻ Nitrite NO ₂ ⁻ Nitrate NO ₃ ⁻ Sulfide S ² ⁻ Sulfite SO ₃² ⁻ Sulfate SO ₄² ⁻ Bromide Br ⁻ Iodide I ⁻ Fluoride F ⁻ Hydride H ⁻ Hydrogen H ₂ Hydroxide OH ⁻ Chloride cl ⁻ Phosphide P ³ ⁻ Phosphate PO ₄³ ⁻ Oxide O 2 –

MemoriseChemical Reactions⚛ (a) ReactionOfAcids Reaction 1 : Acids + Reactive Metals Acids(aq) +reactive Metal(s) →salt(l) + Hydrogen Gas(g) → Insert a lighted splint into the test tube. Hydrogen gas extinguishes the burning splint with a squeaky ‘pop’ sound. Reaction 2 : Acids + Base Base: Metal Oxide(___O) or metal Hydroxide(__OH) Acid(aq) + base(aq) →salt(aq) + water(l) → there’s no test for this Reaction 3 : Acids + Metal Carbonate Metal Carbonate(___CO ₃ ): is a metal + carbonate polyatomic ion (CO ₃ ) Acid(aq) + metal carbonate →salt(aq) + water(l) + carbon dioxide(g) → Bubble the gas through limewater. Carbon dioxide gas produces a white precipitate (an insoluble white solid) inlimewater.

(a) ReactionOfBase Reaction 1 : Base + AmmoniumSalt Ammonium salts: compounds that contain the ammonium polyatomic ion(NH ₄ )combined with another species such as chloride ion, nitrate ion or sulfate ion Ammonium salt(aq) + base(aq) →salt(aq) + water(l) + ammonia(g) → Place a piece of moist red litmus paper at the mouth of the test tube. Ammonia gas turns damp red litmus paper blue. Note: Ammonia also has a strong, pungent odour. MemoriseRomanNumerals, compoundnumbers(?idkwhat tocall it bro)⚛ 1) RomanNumerals Only occurs for lead, copper and ironeg.(II),(III) 2)Compoundnumbersfornonmetal elements(covalentonly) 1.mono __ ₁ 2.di __ ₂ 3.tri __ ₃ 4.tetra __ ₄

5.penta __ ₅ 6.hexa __ ₆