OCR Module 2 Welcome to your OCR Module 2 Three isotopes of a newly discovered element X are 117-X (relative abundance 3), 119-X (relative abundance 5), and 121-X (relative abundance 7). What is the relative atomic mass of element X? 119.5 0.179 120 118.3 The atomic mass of the ion of an element A+ is 23 and it has 10 electrons. How many protons, neutrons and electrons are present in the neutral atom A? 11 protons, 12 neutrons, 11 electrons 11 protons, 12 neutrons, 10 electrons 10 protons, 13 neutrons, 10 electrons 12 protons, 11 neutrons, 11 electrons What is the concentration of the solution when 16g of sodium chloride is dissolved in 250 cubic centimetres of water? 1.09M 0.9M 0.001M 0.1M Calculate the mass of nitrogen gas that has a pressure of 100 kPa, a temperature of 25 degrees centigrade, and a volume of 500 cubic centimetres (R = 8.31). 0.56g 1g 0.0202g 0.2g How many atoms of magnesium are present in an 18g sample of magnesium metal? 4.5x10<sup>23</sup> 6.022x10<sup>23</sup> 4x10<sup>22</sup> 0.75x10<sup>23</sup> Which of the following conclusions can be made if percentage uncertainty due to apparatus is less than the percentage difference between the actual value and the calculated value? There is a discrepancy in the result Error is due to sensitivity of the equipment Equipment with smaller scale divisions must be used There is negligible error Which of the following is the definition of a Bronsted-Lowry acid? A proton donor A proton acceptor An electron donor An electron acceptor The oxidation number of carbon in carbonate ion is? +4 -4 +2 -6 All uncombined elements have an oxidation number of what? Zero 1 -1 2 Iron reacts with hydrochloric acid to form iron(II)chloride and hydrogen gas. Which of the following is true about iron in this reaction? It has oxidised It has reduced It oxidises and reduces at the same time Its oxidation state does not change What is the correct order of energies of subshells? 1s < 2s < 2p < 3s < 3p < 4s < 3d 1s > 2s > 2p > 3s > 3p > 3d > 4s 1s < 2s < 2p < 3s < 3p < 3d < 4s 1s > 2s > 2p > 3s > 3p > 4s > 3d How many orbitals are there is the d subshell? 5 10 3 6 What type of bonding exists in ammonium chloride (NH4Cl)? Ionic, covalent, dative covalent Ionic, covalent Ionic, dative covalent Covalent, dative covalent What is the bond angle in chlorine trifluoride (ClF3) is approximately equal to? 89 degrees 107 degrees 120 degrees 104.5 degrees Which of the following statements is correct?I. Polar molecules are symmetricalII. Non-polar molecules can contain polar bondsIII. Van der Waals forces occur due to temporary dipoles II and III only I, II and III I and III only I and II only Time is Up!