Mrs. Jensen's Chemistry Class

Do you need more help with….Mixtures: Solutions/Suspensions/Colloids

on October 3, 2016
First we will review relative density by making a density column using vegetable oil, rubbing alcohol, water, and pancake syrup. All of the liquids will have a volume of 50 milliliters. However, each liquid will have a different MASS. This is because water has less MATTER in it than syrup does ( syrup is much “heavier”). Since they have different masses, they will have different densities. This is an experiment that you can do at home with your family! Make sure to have the same amount of each liquid though :). Over the week, I will upload our journal entries including illustrations and our data.
Here are some density column examples:
          
Following are some links to learn more about density columns and relative density:
Wednesday thourhg Friday we will focus on mixtures and solutions. These are both, again, ways to describe matter; in other words,  being a mixture or a solution is a physical property!
 
MIXTURE:
  • a combination of two or more objects
  • objects keep their physical properties — THEY STAY THE SAME!
  • For instance, lets say I put yellow skittles in a bowl with pretzels. Did the pretzels change? NO. Did the skittles change? NO! ( not unless your hand is sweaty). THIS IS A MIXTURE! Two, or more things, together that KEEP THEIR PROPERTIES.
  • Other examples include:
    • lucky charms cereal
    • water and sand ( nothing dissolves)
    • water and pepper
    • water and oil
    • marbles and paper clips
    • spaghetti and meatballs
    • laundry hamper full of socks and t-shirts
    • your pencil box/bag
  • Usually, these are easy to separate— you can use tools like:
    • tongs
    • tweezers
    • a sieve or strainer
    • coffee filter
    • magnet
    • adding water ( less dense items will be buoyant and float)
Here are some illustrations of mixtures, as well as some links to help you further understand what a mixture is, and how to identify one:
          
SOLUTION:
  • A special kind of mixture where something DISSOLVES
  • Properties of the objects change– SOMETHING DISSOLVES
  • Some objects dissolve better than other things
    • Powdered sugar dissolves better than sugar crystals
    • SOLUBILITY  refers to the objects ability to DISSOLVE
  • These are harder to separate– usually you would evaporate out the water
    • this can be done by boiling the solution, or placing it somewhere warm for a few days
    • The water will evaporate, and leave the other object ( the one that dissolved) behind
  • Examples include any mixture where AN OBJECT DISSOLVES!!!!
    • salt water or ocean water
    • kool-aid
    • sweet tea
    • lemonade
    • our atmosphere ( many gases, including oxygen, dissolve into one another)
    • chocolate milk
    • dish soap