Topic 2 Lesson 1-Mixtures and Solutions

Types of Mixtures

• mixture- made of two or more substances that are together in the same place, but their atoms are not chemically combined

• homogeneous mixture- one that features distinct components that can be easily identified and distinguished throughout the mixture

• examples of heterogenous mixture- bowl of salad

• heterogeneous mixtures components are not spread out evenly throughout the mixture

• homogeneous mixture- mixtures often look the same throughout the entire mixture

• examples of homogeneous mixture- saltwater, honey, soy sauce

Separating Mixtures

• mixtures of different size particles can be filtered

• magnetic components can be separated by a magnet

• liquid mixtures can be heated until some components evaporate and others left behind as solids (an example of this is saltwater)

Classifying Mixtures

• colloid- a heterogeneous mixture, has small undissolved particles that do not separate or settle

• an example of a colloid is milk

• particles are too small to see, but big enough to scatter light

• examples of particles are paint, whipped cream, fog, smoke

Suspension

• suspension- a mixture with particles that can be seen, easily separated by settling

• examples of suspension are oil+vinegar salad dressing and muddy water

Solution

• solution- homogeneous mixture of a solvent and has one or more solutes and has the same properties throughout a mixture in which one substance is dissolved in another

• an example of a solution is grape juice

• solvent-the part of the solution that is the largest amount, it dissolves the other substance

• solute- substance that is dissolved by the solvent

• ex: in grape juice, water is the solvent, sugar and other ingredients are the solutes

• air is a solution; a mix of oxygen, nitrogen, and other gases

  • nitrogen is the solvent because it makes up most of the air

• stainless steel- a solid solution, a mix of iron, chromium and nickel

• molecular compounds break up into individual molecules in water

• an example of a molecular compound is table sugar

• polarity is important to dissolving

• most non-polar molecules do not dissolve in water

• table salt is made of an ionic compound, salt dissolves in water

Concentration

• solutes raise the boiling point of a solution above the solvent

• boiling point, freezing point, and density are physical properties of solutions that are affected by concentration

• a concentrated solution will have a lot of solute

Solubility

• solubility- the measure of how much solute will dissolve in a solvent at a given temperature

• a solution that can no longer dissolve a solute is saturated

• as the temperature increases, solids become more soluble; the solubility of gases decrease (for example air)

Temperature

• temperature- raising the temperature of the solvent increases the solubility of a solid solute

• pressure-affects the solubility of gases, has little effect on the solubility of solids

• temperature can affect the carbonation in a soda

  • carbon dioxide is less soluble in warm temperatures, so a cold soda would have more carbonation than a warm one would

Examples of Homogenous Mixtures

• sugar

• gasoline

• consistent composition throughout

• cooking oil

• components indistinguishable

• evenly mixed, uniform appearance

• single phase

• perfume

Examples of Heterogeneous Mixtures

• mixed nuts

• non-uniform composition

• different properties throughout

• dirt

• ice cream

• mixture with visibly distinct components

• chunks or layers present

• vegetable soup

Henry’s Law

• If the pressure of a gas over a liquid increases, the amount of gas dissolved in the liquid increases proportionally

• ex: gas pressure: ⬆ and gas solubility ⬆