Mixtures and Solutions – Foss Kit



Study Guide for Mixtures and Solutions Test

Multiple Choice:

|separating solutions | |

|description of 3 mixture separations: gravel/water, powder/water,| |

|salt/water | |

|most soluble: | |

|citric acid, salt, Epsom salt, baking soda | |

|least soluble: | |

|citric acid, salt, Epsom salt, baking soda | |

|saturated | |

|how temperature affects saturation | |

|crystals | |

|what makes a solution have a | |

|high concentration | |

|how dilute a solution | |

|concentration | |

|evidence of a chemical reaction | |

Short Answer:

|making a solution | |

|saturated solutions | |

|concentrated solutions | |

|separating solutions | |

|evidence of chemical reactions | |

|how temperature affects saturation | |

|similarities of mixtures and solutions | |

|differences of mixtures and solutions | |

|examples of mixtures | |

|examples of solutions | |

Mixtures and Solutions – Foss Kit

Investigation 1: Separating Mixtures

1. Making and Separating Mixtures

• Mixture

─ Two or more materials stirred together

─ Chocolate Milk, cereal, trail mix, egg salad

• Property

─ A characteristic of an object

─ Something you can observe

─ Size, color, shape, texture

• Solution

─ A special mixture formed when a material dissolves in water

─ Must be transparent

─ Apple juice, salt water, tea

• Dissolve

─ Process in which one material disperses uniformly into another material

─ The first material seems to disappear

2. Separating a Salt Solution

• The mass of a mixture = the sum of its parts

3. Observing Crystals

• Evaporation

─ Liquid turns to a gas and disperses into the air

─ Leaves any dissolved material behind

• Crystal

─ The solid form of a material that can be identified by its properties (size, shape, pattern)

• When a solid evaporates, it leaves the dissolved solid material behind

• Sometimes the evaporation material forms a crystal

Investigation 2: Reaching a Solution

1. Salt Saturation

• Solvent

─ The liquid into which the solid material dissolves

─ Water is the universal solvent

• Solute

─ The material that dissolves

• Saturated Solution

─ When a solute dissolves in a solvent until no more will dissolve

• Salt will dissolve in water until it reaches saturation

• No more salt will dissolve once saturation is reached

2. Citric Acid Saturation

• Solubility

─ The property substances have of dissolving of solvents

─ Which is more soluble in water: salt or citric acid

• (citric acid is 4 times more soluble)

3. The Saturation Puzzle

• Journal:

─ Which of the 3 chemicals tested is most soluble in water? Least soluble?

4. Comparing the Crystals

• Some crystals are formed with characteristic shapes that can be used for identification

Investigation 3: Concentration

1. Soft – Drink Recipes

• Concentration

─ The amount of material dissolved in a measure of liquid

─ The more material dissolved in an amount of liquid, the more concentrated the liquid

─ Usually darker color

• Dilute

─ to make a solution less concentrated, usually by adding more water

─ usually lighter color

• Volume

─ The 3-dimensional space occupied by something

─ In this investigation it is the amount of liquid

• As the amount of solute in a solution increases, the concentration goes up

2. Salt Concentration

• When equal volumes of two solutions are compared on a balance, the heavier one is more concentrated

3. Mystery Solutions

Investigation 4: Fizz Quiz

Chemicals used:

1. Citric Acid – Sour flavor, used in sodas and candy

2. Baking Soda – Baking, antacid, fire extinguisher, deodorize fridge

3. Calcium Chloride – Salt used to melt ice

1. Chemical Reactions

• Baking soda – least soluble in water

• Precipitate

─ A solid material that forms as a product of a reaction

• Chemical reaction

─ When 2 or more materials are mixed together and a change occurs

─ A reaction forms new materials with properties that are different from the original materials

• Change – the process of becoming something different

• Sometimes when 2 or more chemicals are mixed, changes take place and new materials form

• Evidence of a chemical reaction – a change, such as heat, gas formation, or precipitate formation

2. Reaction Products

• Crystal observation

─ draw

─ listed chemicals that went into the reaction

─ list chemicals that came out of the reaction

• if a liquid is a solution, it might be separated by evaporation

3. Reaction in a Zip Bag

• Reactants

─ When 2 chemicals react when they are mixed, the chemicals are called reactants

─ In the observation made above, calcium chloride and baking soda are the reactants

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