<p>1) Calculate the percentage by mass of sulphur in CuSO4.5H2O.</p><p>2) Calculate the molar mass (g mol-1) of the following gases:</p><p>A: 0.32 of gas X occupies 48 cm3 at rtp</p><p> b) 0.355 g of gas Y occupies 120 cm3 at rtp</p><p>3) Stibnite is an ore containing 5% by mass of the compound antimony sulphide, Sb2S3. Tgh metal is produced by reduction of antimony sulphide by iron.</p><p>Sb2S3 + 3Fe → 2Sb + 3FeS</p><p> a) Calculate the number of moles of Sb2S3. In 680 Kg of stibnite, assuming the sample </p><p> contains 5% by mass of Sb2S3.</p><p> b) Calculate the maximum mass of antimony that could be obtained from 680 Kg of stibnite.</p><p>4) A solution of hydrochloric acid of volume 25.0 cm3 was pipetted onto a piece of marble which is calcium carbonate. When all action had ceased, 1.30g of the marble had dissolved. Find the concentration of the acid </p><p>Equation: CaCO3 + 2HCl  CaCl2 + CO2 + H2O</p><p>5)What volume of 0.1 moldm-3 hydrochloric acid would be required to dissolve 2.3 g of calcium carbonate?</p><p>Equation: CaCO3(s) + 2HCl(aq)  CaCl2(aq) + CO2(g) + H2O(l)</p><p>3 6)2.05 g of the carbonate of an unknown alkali metal (X2CO3) required 8.9 cm of 2.0 moldm-3 hydrochloric acid to completely dissolve it. What was the relative atomic mass of the metal and which metal was it?</p><p>Equation: X2CO3(s) + 2HCl(aq)  2XCl(aq) + CO2(g) + H2O(l) 7)Succinic acid has the formula (CH2)n(COOH)2 and reacts with dilute sodium hydroxide as follows: (CH2)n(COOH)2 + 2NaOH  (CH2)n(COONa)2 + 2H2O 2.0 g of succinic acid were dissolved in water and the solution made up to 250 cm3. This solution was placed in a burette and 18.4 cm3 was required to neutralise 25 cm3 of 0.1 moldm-3 NaOH.</p><p> a) Calculate the number of moles of NaOH used in the reaction</p><p> b) Calculate the number of moles of succinic acid which were neutralised.</p><p> c) Calculate the molar mass of succinic acid.</p><p> d) Deduce the value of n. 8. Sodium carbonate exists in hydrated form, Na2CO3.xH2O, in the solid state. 3.5 g of a sodium carbonate sample was dissolved in water and the volume made up to 250 cm3. 25.0 cm3 of this solution was titrated against 0.1 moldm-3 HCl and 24.5 cm3 of the acid were required.:</p><p>Na2CO3 + 2HCl  2NaCl + CO2 + H2O</p><p> a) Calculate the number of moles of hydrated calcium carbonate</p><p> b) Calculate the amount in g of anhydrous salt.</p><p> c) Calculate the amount in g of water of crystallisation</p><p> d) Calculate the value of x</p><p>3 9) 25 cm of a sample of vinegar (CH3COOH) was pipetted into a volumetric flask and the volume was made up to 250 cm3. This solution was placed in a burette and 13.9 cm3 were required to neutralise 25 cm3 of 0.1 moldm-3 NaOH. Calculate the molarity of the original vinegar solution and its concentration in gdm-3, given that it reacts with NaOH in a 1:1 ratio.</p><p>1) 12.08%</p><p>2) A 160 gmol-1</p><p>B= 71 g mol-1</p><p>3)a= 10 mol</p><p>B= 24.4 kg</p><p>4. 1.04 moldm-3</p><p>5. 459 cm3</p><p>6. 85.2, Rb</p><p>7. x = 10</p><p>8.1.80 oldm-3, 108 gdm-3 8. n = 2</p>