Basic Chemistry III Vladimíra Kvasnicová

Add formulas: sodium sulfite potassium phosphate ammonium hydrogen phosphate lithium dihydrogen phosphate calcium hydrogen carbonate silver sulfide zinc sulfate potassium permanganate sodium hypobromite barium nitrate hydrargyric chloride

Add formulas: sodium tetraborate decahydrate potassium aluminium sulfate sodium aluminium sulfate dodecahydrate ammonium carbonate calcium sulfate hemihydrate (hemi = ½) zinc sulfate heptahydrate potassium dichromate potassium magnesium fluoride ammonium magnesium phosphate led(II) chloride fluoride cupric biscarbonate difluoride (bis = twice)

Important terms: reactants / products stoichiometric coefficients substance amount relative atomic / molecular mass molar mass density concentration (molar, percent)

molar concentration (= molarity) M = mol/1000 mL 1M solution  1 mol of a solute is found in 1000 mL (= 1L) of the solution 0,5M solution  0,5 mol of a solute is found in 1000 mL (= 1L) of the sol. percent concentration % = g/100g 1% solution  1 g of a solute is found in 100 g of the solution 0,5% solution  0,5 g of a solute is found in 100 g of the solution

Chemical reactions exercises Calculate the mass of KOH and the volume of 96% H 2 SO 4 needed for preparation of 25 g of K 2 SO 4 Molar masses (MW): KOH g/mol H 2 SO g/mol K 2 SO g/mol Density of 96% H 2 SO 4 : g/cm g KOH and 7.99 mL of 96% H 2 SO 4 1.write related chemical equation 2.balance the equation 3.find the stoichiometric ratios of reacting substance amounts 4.convert substance amounts to mass (KOH) or volume (H 2 SO 4 )

Chemical reactions exercises 5 mL of 0,5 M KMnO 4 were mixed with 25 mL of Na 2 SO 3, the reaction processed quantitatively. Calculate concentration of Na 2 SO 3 (both: molarity and %). KMnO 4 + Na 2 SO 3 + H 2 O → MnO 2 + Na 2 SO 4 + KOH n = Molar masses (MW): Na 2 SO g/mol KMnO g/mol 0.15M = 1.89% Na 2 SO 3 1.balance the chemical equation 2.find the stoichiometric ratios of reacting substance amounts 3.convert substance amounts to molar and % concentrations

Chemical reactions homework 100 g of FeS was used for the chemical reaction: FeS + HCl → FeCl 2 + H 2 S 1.balance the equation 2.calculate what volume of HCl (36%, density = 1,18 g/ml) was needed for the reaction 3.calculate mass of FeCl 2 prepared by the reaction A r (Fe) = 55,8 A r (S) = 32,1 A r (Cl) = 35,5 A r (H) = 1,0

Exercise Describe dissociation of the salts: KNO 3 → K 2 CO 3 → Na 3 PO 4 → Na 2 HPO 4 → NaH 2 PO 4 → NH 4 HCO 3 → What is the osmolarity of the 1M solutions?