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Unformatted text preview: Suppose that you are given 50 L of a solution containing fluoride ions at a concentration of 0.025 mol/L and are told to reduce the concen-tration to 1 mol L, a level which is considered safe for drinking, and thus for disposal by pouring into a drain. You decide to do this by dissolving calcium nitrate into the solution since (a) calcium ions are mostly harmless, and (b) calcium fluoride is insoluble. The calcium fluoride can be removed by filtration and disposed of as solid waste, which is much cheaper than trying to dispose of a large volume of liquid waste. What mass of calcium nitrate will you need to add to the 50 L of solution? [10 marks] 6. If you extracted all the oxygen from 1 L of water which is in equilibrium with the atmosphere at sea level and stored this oxygen in gaseous form in an (initially empty) 1 L container, what pressure would it exert at 25 C? [7 marks]...
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- Fall '06