Heterogeneous Mixtures

General Chemistry Index

Where are we going with this? The point of this deck is to give the background information and examples so that we can differentiate between substances (pure and mixtures) based on physical and chemical properties.

Heterogeneous Mixtures

Greek fun: Hetero = different; geneious = origins

Heterogeneous mixtures are combined in such a way that the molecules of the substances making it up can be separated using simple processes.

Heterogeneous mixtures:

• The parts of the mixture are noticeably different from one another. 
• The composition is not the same throughout.
• You CAN divide out different parts…like picking tomatoes out of a salad!

Seriously? Good thing atoms and molecules got introduced elsewhere.

So, basically, if you have a bunch of stuff in in a heterogeneous mixture, you can, by some means, separate them back into the substances that make it up (even if it is ridiculously difficult, such as separate salt from pepper mixed into a single shaker).

The parts of the mixture are noticeably different from one another. 

The concept is pretty easy at a large scale. If you have a bucket full of pennies and quarters, you can still see each penny and each quarter. You could take out on of either a penny or a quarter easily.

The composition is not the same throughout. 

Again easy at a large scale. If you have a bucket full of pennies and quarters grabbing a handful of coins would result in different dollar amounts with each grab. The composition is not uniform. One handful might have have 15 quarters and 10 pennies. The next 13 quarters and 12 pennies.

 You CAN divide out different parts.

Back to that bucket of pennies and quarters… It would be easy to come up with a way to sort them (*cough cough* Coinstar), even if you just dumped them on a table and used your fingers.

On a small scale…

Mixing things that are really small complicates the process (illustrated with the bucket of coins) but the concepts hold. For instance a cup of sand and salt mixed together:

• If you look really close, you could identify the salt from the sand.
  
  
• A random spoonful might have 1.1 bazillion salt grains and 1.2 bazillion sand grains. The next random spoonful might have 1.3 bazillion salt grains and 1.1 bazillion sand grains.
   
• If you were very determined, you could put some out on a table and use a magnifying glass to pick out one grain of salt.

Going even smaller…

Even down to the molecular level, the concepts stay the same.