Acids ∙ Waikawa

1. Acids∙ Waikawa An acid is a substance which ionises (splits into ions) when placed in water, producing hydrogen ions (H+) E.g. Sulfuric acid H2SO4H+ + HSO4- Acids are classified as strong or weak depending on the number of H+ ions produced when in water.

2. Hydrochloric (HCl), sulfuric(H2SO4), and nitric acids are classified as strong acids because 100% of their molecules ionise when placed in water. Ethanoicacid, citric acid, and tartaric acid are classified as weak acidsbecauseless than 100%of their molecules ionise when placed in water.

3. Acids Reactions Acid + Metal __________ + ___________ __________ + ___________ Acid + Carbonate ________ + ________ + ________ ________ + ________ + ________ +Fe HCl Iron metal Hydrochloric acid +CaCO3 HCl Hydrochloric acid Calcium carbonate

4. Acids Reactions Acid + Bicarbonate _______ + _______ + _______ _______ + _______ + _______ +NaHCO3 HCl Hydrochloric acid Calcium carbonate Bicarbonates have the same products as carbonates when reacted with acids. Bicarbonates just have an extra ‘H’ Bicarbonate ion: HCO3- Carbonate ion: CO3-

5. Elements: Substances made up of 1 type of atom, e.g. diamond (C only). Elements in same group = similar properties b/c all have same # of e- in v.E level Groups (e- config) Arranged in P.T. in order of A # 2 3 1 p (+ve) e- Periods (# E levels) 1 1st E level 2 Indicators: Used to indicate if substance = acid or base. They ∆ colour according to pH.e.g. litmus/ U.I + A # = # of p (= to # e-) 3 + e- Max # e- n (Ø) Each element in period = same # E levels for e-s. 1st + last element = v. diff. b/c diff. in e- + p # e Weak/ dilute. ac: produce small amounts of H+. (<100% ionise). Atoms E level ∆ colour depending on amount of OH- /H+ produced # indicating acidity/alkalinity Symbol M # = # of p + # of n e- (-ve) [O.N.E] Acids e- arrangement e- arrangement Ionises to produce H+ ions when placed in H2O Strong/ conc. ac: produce large amounts of H+. (100% ionise). e.g. Cl atom: 2, 8, 7 Cl- ion: 2, 8, 8 Atoms lose or gain e- in order to achieve a full v.shelland ∴ be in a lower, more energetically favourable state Strong ac = many H+ produced. Many H+ turn U.I red Shells/ E levels: Found at diff. distances from nucleus (Put in H2O) e.g. H2SO4 → H+ + HSO4- Ions e- e- e- e- 1st shell (or E level) e- Reactions e- e- e- e- e- e- 2nd shell e- e- e- e- e- 11p 12n 11p 12n e- e- e- e- (Polyatomic ions)*brackets OH- NO3- HCO3- SO42- CO32- NH4+ e- e- e- e- e- e- 3rd shell (also v.shell) e- e- { e- e- e- e- e- e- e- e- 17p 18n 17p 18n e- e- e- e- e- is transferred e- e- e- e- e- e- Cl Ion formation: Atoms become ions. Ion = atom w/ + or – electrical charge. e- e- e- e- e- e- p = 17; e = 17; n = 18 nucleus (p + n) e- e- e- e- Ionic compounds (salts): Ions with oppos. charges are electrostatically attracted to one another. Na p = 11; e = 11; n = 12 Na+ Cl- e.g. Ion w/ 1 +ve charge is ∴ electrostatically attracted to an ion w/ 1 –ve charge (∴ 1:1 ratio) NaCl 1:1 ratio Cl- Ion charge = diff. in p & e- # p = 17; e = 18; n = 18 Chemical formula Must be in correct order and ratio Non-metal 2nd Na+ e.g. Cl- = 1 more -ve e- than +ve p. ∴ charge = 1- Shows amount of atoms in substance, e.g. 1 Na+ and 1 Cl- p = 11; e = 10; n = 12 Metal 1st