Food Chemistry

 Distinguish between pure substances and mixtures.  Compare homogeneous and heterogeneous mixtures.  Define solutions.  Distinguish between a solute and solvent.  Recognize water as a universal solvent.  Understand the processes of solubility and saturation.

Matter  Anything that has mass and takes up space. Physical Properties  A characteristic that can be observed or measured without changing the substance  Solid  Liquid  Gas Chemical Properties  The ability of a substance to react with other substances

www3.delta.edu

 Made of only one kind of material and has definite properties Elements  Sodium, Carbon, Iron Compounds  Table salt, water, sugar

 A combination of two or more substances in which each substance keeps at least some of its original properties.  Physically blended, not chemically. Homogeneous Mixtures Heterogeneous Mixtures

 The same in every part of a given sample. Examples: salt water, milk, air, cola Another name for a homogeneous mixture: Solution – one substance is dissolved in another Solution SoluteSolvent

SOLUTESOLVENT  The substance that is dissolved  Sugar  Salt  The substance that dissolves another substance  Water Water is recognized as a universal solvent. This can be a problem with vitamins and minerals dissolving in cooking water.

 Individual substances are dissimilar and can be recognized by sight. This is also known as “Immiscible” Examples: salad, potato soup, Italian dressing

Unsaturated Solution:  A solution that contains less solute than can be dissolved in it at a given temperature. Saturated Solution:  A solution that contains all the solute that can be dissolved at a given temperature.

 The maximum amount of solute that can dissolve in a given quantity of solvent at a specific temperature.  The solubility of most solids dissolved in a liquid increases as the temperature increases. Example: Sugar dissolves faster in boiling water.  The solubility of gas decreases as the temperature increases. Example: A warm can of soda will go flat faster than a cold can of soda.

 The amount of solute in a solution affects the temperature at which the solution boils or freezes.  The more solute present in a solution, the higher the boiling point and the lower the freezing point. Example: Ice cream is still soft in the freezer because of the sugar dissolved in the water.

Your table now has 4 glasses. Add 4 different solutions to the glasses and identify the type of mixture as homogeneous or heterogeneous. Glass # 1 – Place 1 drop of food coloring in your glass of water and stir. Glass # 2 – Add ¼ cup oil to the water. Glass # 3 – Add ¼ cup vinegar the water. Glass # 4 – Add ¼ cup vinegar to the oil.

 Make Iced Tea using both cold and hot water.  Compare the flavors and answer the questions to review the scientific theme of the week.