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Solutions. Solutions are a homogeneous mixtures. Copper Chloride solution Copper (II) chloride + Water. Ocean Water Salt + Water. Syrup Sugar + Water. Solute and Solvents. The substance being dissolved is the solute . The substance doing the dissolving is the solvent. Solute :
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Solutions • Solutions are a homogeneous mixtures. Copper Chloride solution Copper (II) chloride + Water Ocean Water Salt + Water Syrup Sugar + Water
Solute and Solvents • The substance being dissolved is the solute. • The substance doing the dissolving is the solvent. Solute: Koolaid Solvent: Water
Increasing the Rate of Solubility • Surface Area -Breaking a solid into smaller pieces greatly increases its surface area. Thus, increasing dissolving rate. • Temperature-increasing the temperature of the solvent speeds up the movement of solvent particles. Thus increasing dissolving rate. • Agitation (stir or shake) - brings more fresh solvent into contact with more solute. • Pressure – pushes the molecules of solute and solvent closer together
Solubility and Concentration • Solubility is the maximum amount of a solute that can be dissolved in a given amount of solvent at a given temperature. • A concentrated solution is one in which a large amount of solute is dissolved in the solvent • A dilute solution is one that has a small amount of solute in the solvent.
Types of Solution • Unsaturated Solution is a solution that can dissolve more solute at a given temperature. • Saturated Solution is a solution that contains all the solute that it can hold at a given temperature. • Supersaturated Solution is a solution that contains more solute than a saturated one at the same temperature.
Adding solute to a solvent lowers the freezing point of the solvent. • Adding solute to a solvent raises the boiling point of the solvent.
Polarity • Some compounds have positive and negative poles. • For example, salt and water have a positive and negative side. • The non-metals in a compound are usually the negative pole while the metals are the positive.
Opposites attract and likes repel • Polar substances line up their poles
Polarity • Golden Rule: Like dissolves like • Nonpolar solute dissolves in nonpolar solvent • Polar solute dissolves in polar solvent
Water • Water is called the universal solvent • Water is very polar and has a structure that allows is to easily dissolved most substances • Water is the most important substance • Life (as we know it) cannot exist without water
Solubility Curves • Solubility curves are used to determine the amount of solute that will dissolve for a given temperature. • Any point ON a solubility curve indicates a SATURATED SOLUTION. • Any point ABOVE the curve indicates a SUPERSATURATED SOLUTION. • Any point BELOW the curve indicated a UNSATURATED SOLUTION.
Properties of water • High melting and boiling point. • Expands upon freezing. • Dissolves a variety of substances easily. • Pure water is rare in nature. • These properties are mainly due to polarity, which will be discussed a bit later.