144 CHINESE NUDE PACK

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Akhil Sabu 11L GCSE Chem Exam Writing

1)i) 22.7 cm3
ii) 0.00232/ 25/1000 = 0.0928 mol/dm3

2) If a solid is divided into smaller pieces, in this case the calcium carbonate, the surface area increases compared to volume. As there is an increase of surface area, there are more particles at the surface of the lump to react.  The HCl can only react with the particles at the surface. This increases the rate of reaction. This is shown in the increase of volume of gas produced. As concentration increases, there is more of the substance available in the same volume. More reactant particles moving together allow more collisions to happen and so the reaction rate is increased. The higher the concentration of reactants, the faster the rate of a reaction will be. 

3) Once the temperature of the water has risen by 30’C, take the burner and record its mass and note down the end temperature on the thermometer. The change in mass of the whole burner is the mass of ethanol needed to raise the water’s temperature by 30’C.
  
4)i) oxygen
ii) Get a test tube and fill with regular water and one with sea water. Use the same volume. Measure two similar nails and place in the test tube. Leave it in there until you see visible results. Take the nail out and measure the nail again and note down the difference in weight and appearance. The predicted result is the nail in the salt water to have more rust as salt water is an electrolyte which can conduct ions, increasing the speed of rusting.
iii)  200g/m2      200 x 0.68 =  136g mass of zinc

5)a) Keep all glassware away from the edge of the table and make sure not to spill any acid or let it touch the skin or eyes. Where safety goggles and a lab coat and gloves. If any acid spills, clean it up and report it.
250/1000 = 0.250    4.3/0.250 = 17.2 g dm-3

c) 24 + 2()  ?  24 + 2(2)

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