What is Chemistry?

1. What is Chemistry? What Our Universe is Made Of Image from: ase.tufts.edu

2. Our Universe • Our Universe is made basically out of a few parts. • These parts make up everything we currently know in the entire Universe; from stars, to light, to people, to some things we have never really seen with our naked eyes.

3. Parts of Our Universe • We currently believe there are 4 components of the universe. • Matter • Energy • Dark Matter • Dark Energy

4. Matter • Matter is anything that has mass and takes up space • This could also be described as anything that has mass and volume Image from: http://asymptotia.com/wp-images/2007/01/dark_matter_millenium_simulation.jpg

5. Matter • Matter is made of atoms • Atoms are the smallest units of matter that can chemically react • Almost everything that you see in your daily life is made of matter

6. States of Matter • Matter comes in 3 common states • Solid • Liquid • Gas

7. Solids • Solids hold their shape and are rigid in their structure • Solids do not flow • Solids have a definite volume and a definite shape • Their atoms are packed closely and can only vibrate

8. Liquids • Liquids are partially rigid • The atoms touch but are able to move past each other • Liquids are hard to compress • They have a definite volume • Atoms can vibrate, rotate, and move

9. Gases • Gases are not rigid • Gases have HUGE spaces in between atoms • Gases are easily compacted • Gases have no definite volume or shape • Gases can fill whatever container no matter what shape or size the container is

11. Checkpoint • Nitrogen is at 25°C. It is contained within a sealed glass jar. The nitrogen is then compressed into a much smaller container. How would you classify Nitrogen? • Jell-O is sitting in the fridge. It cannot be packed any smaller than the size that it is. It can jiggle but stays in the shape of a rectangle. How would you classify Jell-O? • Extra gravy is stored in the fridge in a rounded bowl. I takes up a definite amount of space. John dumps the gravy on a plate and it stays in the shape of bowl at first. After about a half hour, it slowly begins to lose its shape and spread across the plate. How would you classify cold gravy? • A LCD TV contains Liquid Crystals. These are molecules (atoms hooked together) that flow, but at a microscopic level, they hold their shape. They fill their container, but they retain a somewhat definite shape. The molecules can rotate, but they all rotate at the same time. How would you classify Liquid Crystals?

12. Changing the states of matter • You can change matter from one state into another. • Solid  Liquid = Melting • Liquid  Solid = Freezing • Liquid  Gas = Evaporating • Gas  Liquid = Condensing • Solid  Gas = Subliming • Gas  Solid = Depositing

13. Energy • Energy is anything that can exert a force on another object • Energy does not have mass or volume • Examples of energy are heat, light, X-rays, gamma rays, electricity, sound, etc. All of these things can exert a force but don’t take up space or have any mass.

14. Matter and Energy • Matter and energy are the only things that we deal with in our daily lives • They are the only things we have on Earth • However, they are not the only things in the Universe • We believe that mass and energy may only make up 5% of all ‘stuff’ in the Universe

15. Dark Matter • Dark Matter is known to take up about 25% of the Universe • It does not absorb light or reflect light so it can’t be seen. This is why it is ‘dark’ • It is known to be there because we cannot see it but it has gravity. It is actually pulling stuff toward it but we can’t see ‘it’ • However, we still don’t know what dark matter ‘is’

16. Dark Energy • It is thought that Dark Energy makes up about 70% of the known Universe • Very little is known about Dark Energy • We think that it exerts a force that is causing the entire Universe to expand • We know it likely exists because of changes in the colours of light as they pass through certain areas in space. This is a complicated topic but is related to the Doppler Effect (the reason sounds change as they get closer or farther away from you)

17. Our Universe • This means that about 95% of the Universe is stuff that we have never seen • All of your daily encounters are will stuff that only makes up 5% of everything that we know exists. • Why is that important? • There is an incredible amount of discovery left to be had in the Universe. There is still SO MUCH that we do not know yet.

18. Chemistry • Since we are still learning what dark matter and dark energy are, we will only be dealing with matter and energy in this class • Chemistry is the study of matter and how it changes • This means we need to learn a little more about matter

19. More about matter • Since matter is anything that has mass and takes up space, there are lots of different types of matter • We have invented some different classifications for different types of matter

20. Classifications of Matter • Matter is usually put into 2 broad classifications: • Pure Substances • Mixtures

21. Pure Substances • Pure substances are made of only one type of particle • They might be made of atoms or molecules • Molecules are 2 or more atoms hooked (usually called bonded) together • Each pure substance has its own unique properties • Examples of pure substances would be sugar, oxygen, silica, manganese oxide, hydrogen peroxide, water, etc.

22. Pure Substances • There are 2 types of pure substances • Elements • A pure substance that is made of only 1 type of atom. They cannot be broken down into simpler substances by chemical reactions • All elements are listed on the periodic table • Examples include oxygen, hydrogen, chlorine • Compounds • Made of 2 or more elements bonded together • Compounds are chemically combined • Examples include water (H2O) or calcium carbonate (CaCO3)

23. Examples • Sodium Chloride (salt) is made out of sodium atoms connected to chlorine atoms. This makes it a Compound. • Aluminum is made of only one type of atom, Aluminum atoms. Copper is made of only copper atoms. This makes them pure elements.

24. Mixtures • As well as pure substances, matter is also found in mixtures • Mixtures are 2 or more types of pure substances • Mixtures are not chemically bonded (hooked together) like a compound is

25. Mixtures • There are 2 types of mixtures • Heterogeneous Mixtures • Homogeneous Mixtures

26. Heterogeneous Mixtures • The 1st type of mixture is a heterogeneous mixture • Heterogeneous Mixtures • ‘Hetero’ means different • A Heterogeneous mixture is a mixture in which you can see the different parts • Examples would include salad dressings or chocolate chip cookies

27. Heterogeneous mixtures • There are 2 types of heterogeneous mixtures • Mechanical Mixtures • A mechanical mixture is when different substances that make up the mixtures are visible to the naked eye • This would be things such as chocolate chip cookies or a bag of trail mix

28. Heterogeneous mixtures • The 2nd type of heterogeneous mixture is a suspension • Suspensions are when large particles are suspended inside of another creating a cloudy mixture • You can see the parts of a suspension with the naked eye • An example of a suspension is a salad dressing. The spices and herbs are suspended in oil and vinegar.

29. Homogeneous Mixtures • The 2nd type of mixture is a homogeneous mixture • Homogeneous • ‘Homo’ means same • A Homogeneous mixture is a mixture of 2 or more substances that look the same • The parts are not distinguishable • Examples would be peanut butter or Kool-aid

30. Homogeneous Mixtures • One specific type of mixture is a homogeneous mixture is a solution • A solution is when one substance is dissolved in another. • The different parts of a solution are not individually visual • Solutions have to be clear but can be coloured

31. Homogeneous mixtures • Another type of homogeneous mixture is a colloid • Colloids look like one substance, but they are cloudy • Examples of colloids are mayonnaise and milk

32. CHECKPOINT • Classify this substance: • Classify this substance: • Classify this substance: • Classify this substance: