Investigating Factors Affecting the Solubility of an Unknown Powder in Water

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Investigating Factors Affecting the Solubility of an Unknown Powder in Water Aim: To investigate the effect of temperature on an unknown powder's solubility. Prediction: As the temperature increases so will the solubility of the powder. I think that the temperature and solubility will be directly proportional - so that at temperature doubles so will the solubility of the powder. Hypothesis: I think this because my scientific theory says that: Molecular solids, like sugar, and ionic solids, salts, both dissolve in water. However, they both dissolve in different ways. The intermolecular forces holding molecules of sugar together are quite weak so when sugar is placed in water these bonds are broken and individual molecules are released into solution. It takes energy to break bonds between the molecules and it also takes energy to break the hydrogen bonds in water. These hydrogen bonds have to be disrupted in order to insert a sugar molecule into the substance. The energy needed for this is produced by the forming of bonds between slightly polar sucrose molecules and polar water molecules. This process works so well between sugar and water that up to 800g of sugar can dissolve in one litre of water. The positive and negative ions in ionic solids, or salts, are held together by the strong force of attraction between particles with opposite charges. When a salt dissolves in water the ions are released and become associated with the polar solvent molecules. Salts separate from their ions when they dissolve in water. There are several factors that affect solubility between different compounds. These are: * Temperature- If the solution process absorbs energy, endothermic, then the solubility will be increased if there is a temperature increase. If the solution releases energy, exothermic, then solubility will decrease. * Molecular Size- If the size or weight of the individual molecules is large then solubility will be low because larger molecules are difficult to surround with solvent molecules. * Polarity- Generally only polar solute molecules will dissolve in

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