Concepts of Matter (warning: teal deer crossing)

Hello fellow chemists! To segway out of an awkward introduction and into the nitty gritty stuff; I present you a warning!

an online phrase commonly used in discussion forums as a response to previous posts that are deemed unnecessarily long and extensive; it’s short for Too Long; Didn’t Read.


Alright! So with our previous knowledge of matter, we are going to explore different concepts around matter. 

HEATH CHEMISTRY: pg 25-34, pg 36-39

Macroscopic changes in matter

• are changes we are able to see with our naked eye

Mixtures and Pure Substances

Mixtures are two (or more) kinds of matter that have visible components, they are also called impure
Solutions are substances that look uniform but are made of two (or more) different kinds of matter

• mixtures scatter light since it contains different visible components.



-insert irrelevant picture and caption here!- 

• this would mean we are able to separate the mixture into it's component parts
• With muddy water; we are able to use alum or lime to produce that a jelly-like substance that can be filtered out. This separates the substance into its component parts
• BUT, what if we described solutions like salt water as a mixture?
• we than imply that we can separate it into different components.

Distillation is the process of heating a liquid until it boils, capturing and cooling the resultant hot vapors, and collecting the condensed vapors.

•  distillation gives us a clue about how solutions can be separated
• With salt water, we are able to boil away the water. This leaves the salt behind, therefore, separating the components.

Only when we can no longer separate substances can we call it pure, however, sometimes it is extremely difficult to separate some substances. This could mean it could take years to discover impure properties of a substance (Say hello to the future advancements in science!)

Pure Substances are matter that are made out of the same particle

• pure substances have a constant boiling point and freezing point
• with water: 0° (freezing point) and 100° (boiling point)
• mixtures usually do not have constant boiling/freezing points

Heating/Cooling Curve

The curve shows the process in which a pure substance changes from solid to gas

The cooling curve is the opposite of the heating curve; going from top left to bottom right.

• Point A
• particles are closely pack together
• Point A-B
• heat is converted to kinetic energy
• substance starts to melt
• Point B
• point where it will either melt or freeze
• Point B-C
• exists in both solid and liquid state
• temperature remains constant
• melting/freezing point
• Point C
• substance is liquid
• Point C-D
• still in liquid state
• kinetic energy increases as particles move faster
• Point D
• begins to change into gas
• Point D-E
• exists in both liquid and gas state
• boiling point
• Point E
• all liquid is now gas
• Point E-F
• gas particles continue to absorb energy and move faster
• temperature increases as heating continues

Chemical and Physical Change

Density is a property of matter that describes volume

Chemical Changes are irreversible 

• produce new matter with different properties than the original matter
• When sugar is heated, it bubbles and turns black as well as a colourless liquid forming. When the black matter and liquid are mixed together it does not change back to the original sugar
• electrolysis
• matter decomposes to form new kinds of matter
• decomposition 
• of a pure substance in which they are separated into components

Physical Change is easily reversed

• it is a change of state 
• it does not appear to create a new kind of matter
• we are able to get the original matter back again
• When moth flakes are heated, the solid material disappears and a liquid is in it's place. If we allow the liquid to cool it changes into a solid. This solid has the same properties as the moth flakes.
• distillation
• of a pure substance in which they are separated into components that already exists

Compounds

Compounds are pure substances that can be decomposed into new kinds of matter

• They appear to be put together from simpler substances
• must be made out of 2 more kinds of atoms
• separated if there is enough energy supplied to separate the components
• not all compounds are made out of molecules; some are made out of elements

Ions are particles that have an electrical charge 

• to know which compounds are ionic and which compounds are molecular is to check them for conductivity

Law of Definite Composition

Law of definite composition is an experimental fact that defines that all compounds have a definite composition

• water is always made out of 2 hydrogens and 1 oxygen
• however, mixtures can have almost any composition desired

Law of Multiple Proportions

Law of Multiple Proportions explains that two or more compounds with different proportions of the same element can be made

• they do not represent the same compound
• they are just multiples of each other
• do not have the same proportions as mixtures

Elements

Microscopic Model is a smaller representation of matter, rather than macroscopic(which is seeing, smelling, touching)

Elements are pure substances that cannot be decomposed into simpler substances

• we assume elements are made out of only one kind of atom
• each element contains a different kind of atom
• elements can exist in solid, liquid, or gaseous state
• elements change state through changes in temperature

Molecules are particles made of more than one atom

• some elements exist in larger units
• have definite shapes and composition

Atoms are the smallest unit of an element

• are usually represented in spheres, spheres are used to suggest the relative size of the atom
• atoms in solid state are closely packed together in an orderly,organized pattern
• atoms in liquid state are still close together but; are no longer in an organized pattern
• atoms in gaseous state move very far apart and move into a straight line until it collides with another atom/container

Still alive and kicking everyone? Don't worry, if you've stayed to the end you get a cookie. But don't lie. I don't give cookies to people who tl;dr. People who tl;dr make me sad.

enjoy your weekend!

-JY