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Herriman High Chemistry
Chapter 16 Section 1 Chemistry Herriman High Chemistry
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Herriman High Chemistry
Essential Questions What is a solution? What are the types of solutions? How can you tell the difference between saturated, supersaturated, and unsaturated solutions? How do you calculate molarity? Herriman High Chemistry
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Herriman High Chemistry
What is a solution? A Homogeneous mixture of two or more substances Homogenous means “the same throughout” Soluble: something that is able to be dissolved Insoluble: something that is unable to be dissolved For a solution to exists the substance being dissolved must be soluble Herriman High Chemistry
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Herriman High Chemistry
Parts of a Solution Two parts of a solution solvent :does the dissolving Solute: part that is dissolved Example: Saltwater Salt is solute Water is solvent Herriman High Chemistry
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How do you tell which is which?
For solid dissolved in liquid solutions, the solute is the solid the solvent is the liquid For other types of solutions The substance with the greater amount is the solvent Herriman High Chemistry
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Herriman High Chemistry
Types of Solutions There are different types of solution based on the states of the compounds that make up the solution Gaseous solutions: gas dissolved in a gas Example: the atmosphere Oxygen and other gases dissolved in nitrogen Solid Solution: solid dissolved in a solid Example: metal alloys like brass Herriman High Chemistry
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Herriman High Chemistry
Types of Solutions Liquid solutions: solid, liquid or gas is dissolved into a liquid Examples: Solid in liquid→ sea water Liquid in liquid → rubbing alcohol Gas in water → carbonation, dissolved oxygen Aqueous solutions are when the solvent is water Herriman High Chemistry
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Herriman High Chemistry
Dissolving The process of dissolving is when the individual particles of the solute become surrounded by the particles of the solvent The solute will only dissolve if it is soluble Herriman High Chemistry
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Herriman High Chemistry
How fast? What factors affect the rate of dissolving and why? Surface area: allows the particles of the solute to be more accessible to the solvent. Stirring/agitation: allows solvent to mix with the solute increasing dissolving rate Temperature: increasing the temperature increases the kinetic energy and speed the particles are moving. The faster they move the more they bump into particles of solvent Herriman High Chemistry
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Herriman High Chemistry
Concentration Concentration is the amount of solute compared to amount of solvent Dilute vs. Concentrated Dilute solutions have relatively less solute Concentrated solutions have relatively more solute DILUTE CONCENTRATED Herriman High Chemistry
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Herriman High Chemistry
Concentration cont. Concentration can also be described in terms of saturated, unsaturated, and supersaturated Saturated: The maximum amount of solute has been dissolved into the solvent Unsaturated: More solute could be dissolved into the solvent so less then the maximum amount Herriman High Chemistry
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Herriman High Chemistry
Concentration (cont) Supersaturated: Contains more solute then the saturated solution A solution can become supersaturated by heating the solution. Herriman High Chemistry
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Measurement of Concentration
There are many ways to indicate concentration Molarity Molality Mole fraction Weight/volume percent Volume/volume percent Parts per million and parts per billion Different fields of sciences use different ways Herriman High Chemistry
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Herriman High Chemistry
Molarity (M) Most useful in chemistry for liquid solutions Definition- how many moles of solute are dissolved in one liter of solution Herriman High Chemistry
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Herriman High Chemistry
Molarity (cont) Find molarity for the following: 4.4 mol NaCl in 13 L H2O 7.6 mol Cu in 53 mL H2O 52 g KOH in 601 mL 65 g Al(OH)3 in 253 mL Herriman High Chemistry
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Herriman High Chemistry
Molarity (cont) Find mol for 43 L of a 7.9 M NiSO4 Find g for 7.1 L of 3.46 M RbCl Find mL for 6.15 mol Fe in 9.8 M soln Find mL for 86 g CaCO3 in a 7.52 M soln Herriman High Chemistry
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Herriman High Chemistry
Essential Questions What is a solution? What are the types of solutions? How can you tell the difference between saturated, supersaturated, and unsaturated solutions? How do you calculate molarity? Herriman High Chemistry
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Chapter 16 Section 1 Assignment
Herriman High Chemistry
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Herriman High Chemistry
Chapter 16 Section 2 Chemistry Herriman High Chemistry
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Herriman High Chemistry
Essential Questions What are ppm and ppb and what are they used for? How do you find molality? Herriman High Chemistry
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Herriman High Chemistry
“Parts Per” Used to measure very, very small concentrations Usually used for trace elements in the earth or toxins present in the environment Parts Per million (ppm) – one out of every one million parts Others are ppb- parts per billion, and ppt parts per trillion Herriman High Chemistry
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Herriman High Chemistry
Molality (m) Useful for solid solutions Definition: number of moles of solute dissolved in one kilogram of solvent Formula: Note: 1.0 g H2O = 1.0 mL H2O 1kg = 1000 g Herriman High Chemistry
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Herriman High Chemistry
Molality (cont) Find the molality for 6.3 mol KCl in 8.00 kg water Find molality for 16.1g Cl2 in 5000g of water Find the molality for 88 g NaOH in 520 g water Find g of solvent given 4.25 m AuNO3 and 52.3 g AuNO3 Find g solute for 760 g solvent of a 9.3 m AlPO4 soln Find the molality of 4.32 g Rb3PO4 in 0.65 L H2O Herriman High Chemistry
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Herriman High Chemistry
Essential Questions What are ppm and ppb and what are they used for? How do you find molality? Herriman High Chemistry
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Chapter 16 Sec 2 Assignment
worksheet Herriman High Chemistry
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Herriman High Chemistry
Chapter 16 Sec 3 Chemistry Herriman High Chemistry
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Herriman High Chemistry
Essential Questions What are the colligative properties? How does adding a solute affect them? How do you find the new boiling and freezing points after the addition of the solute? Herriman High Chemistry
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Colligative Properties
Physical properties that are affected by the concentration of the solute in the solution Vapor Pressure Reduction Boiling Point Elevation Freezing point depression Osmotic Pressure Herriman High Chemistry
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Vapor Pressure Reduction
In a liquid, molecules are constantly moving from the liquid phase to the gas phase and back again Vapor pressure is the pressure of the gas “pushing” on the liquid Herriman High Chemistry
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Vapor Pressure Reduction (cont)
By adding a solute, it prevents some of the molecules escaping into the gas phase Because there are fewer molecules in the gas phase, the pressure is reduced Herriman High Chemistry
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Vapor Pressure Reduction (cont)
The decrease in a solution’s vapor pressure is proportional to the number of particles the solute makes in solution. Which would have the lowest pressure? Herriman High Chemistry
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Boiling Point Elevation
A liquid boils when its vapor pressure is equal to the external pressure because at this point the molecules can escape into the gas phase Adding a solute reduces vapor pressure and increases the energy needed for the vapor pressure to equal the external pressure The increase in energy results in the boiling point increasing which is called Boiling Point Elevation Herriman High Chemistry
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Herriman High Chemistry
What happens? What happens to ice when you add salt? The ice melts Why do you think it melts? Herriman High Chemistry
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Freezing Point Depression
The freezing point of a liquid is when the vapor pressure of the liquid and the solid are equal to each other Adding a solute reduces the vapor pressure of the liquid which lowers the temperature at which the solid and liquid pressures are equal This reduction in temperature causes a lower freezing point called Freezing Point Depression Herriman High Chemistry
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Herriman High Chemistry
Osmotic Pressure Osmosis is the flow of a solvent from low concentration to high concentration of the solute through a semi-permeable membrane Occurs in cell membranes Osmotic pressure increases when concentration increases Herriman High Chemistry
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Herriman High Chemistry
Essential Questions What are the colligative properties? How does adding a solute affect them? How do you find the new boiling and freezing points after the addition of the solute? Herriman High Chemistry
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Chapter 16 Section 3 Assignment
Herriman High Chemistry
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