Phases of Matter

Here’s an awesome prezi Erin made, which describes the phases of matter. What I’d like to include is this:

Latent heat of vaporization is used for vaporizing and condensing, it’s just a matter of what the energy is coming from.

Same applies to the latent heat of fusion, which is used for melting and freezing

1 year ago
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Acids and Bases

Today, we’re going to discuss what acids and bases are, and how they are measured on the pH scale.

The pH scale goes from 0 to 14, 7 being “neutral.” Anything from 1 to 6.99 is acidic, and anything from 7.01 is basic. The closer something is to 0, the more acidic it is, and the closer to 14 it is makes it more basic.

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We measured ph with litmus paper, which, when reacted with an acid or base, turns a certain color as a result of a chemical reaction. The above colors are displayed on the litmus paper whenever it is coated in an acid or base.

But what exactly are acids and bases?

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Basiclly, acids have much more hydrogen (h+) and bases have more hydroxide (OH-)

For example, lye is a base because it has more OH- than H+

1 year ago
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Aluminum + Copper Chloride = Chemical Reaction!

Today, we’re going to talk about how the chemical reaction between aluminum and copper (2) chloride in a solution of water. First of all, what is aluminum? What is copper chloride?

Aluminum is a metal that is very chemically reactive, and not very dense.image

Copper Chloride is a blue powdery compound formed between the metal copper and the nonmetal chlorine.

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In order to create this chemical reaction, we formed a solution of copper chloride and water. The water actually splits apart the ionic bond between the copper and the chlorine.

But how does it do that?

The copper is a metal, so it is going to transfer an electron to chlorine when they bond, so both become ions, which creates this ionic bond. Now, water is made up of what’s called polar molecules, which are covalently bonded. But unlike most bonds, polar molecules are actually “electrically lopsided.” So it may be neutral, but one end is more positive and one end is more negative.  Anyways, when the ionic bond is submerged in water, the positive copper ion is attracted to the negative sides of the water molecules, and the opposite happens for the negative chlorine ions. But the main point is that the bond between the ions cannot hold them together any longer.

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So we have our copper and chlorine solution, and then we add aluminum. What is about to happen is called a single replacement solution, which is written as

                A + BC (arrow) B + AC

A reacts with a compound of B and C to produce B and a compound of B and C

With that in mind, the copper and the aluminum replace each other. Aluminum dissolves into the water as it bonds with the chlorine to make aluminum chloride, and the copper comes out of solution, which is why the aluminum appears to be missing, and there is pure copper at the bottom of the beaker.

Why is there left over aluminum in some beakers, but none in others?

Well, whenever a chemical reaction happens, the reactants and the products will always be in the same amount, meaning no matter can be created or lost. So, if there is a little copper chloride, it will replace only a little aluminum. And if there is a lot of aluminum, it will replace a lot of aluminum. With that said, the more copper chloride you added to the solution, the more aluminum that was replaced.

1 year ago
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Methods of Heat Energy Transfer

There are three methods that heat can be transfered, which are convection, radiation, and conduction.

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Conduction is the transfer of heat from one substance to another through molecular collisions. Solids are generally better conductors than liquids or gases since their molecules are closer together and collide more often. That is why we call liquids and gases thermal insulators. Examples of conduction are tea kettles, cooking any food on the stove, or even melting ice with your hand. When you touch it, the heat energy travels from the warmer source (you) to the colder source (the ice).

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Convection is similar to conduction in the fact that it needs a material medium to transfer heat, but it doesn’t do so through solids. Rather, it is the transfer of heat by movement of a substance from one position to another, usually through liquids or gases. Here’s how it works:

  1. In a container of water, the water nearest to the heat source becomes hot. Since its temperature is rising, its molecules spread out making it less dense, so it rises to the top.
  2. There, it is further away from the heat source and becomes cooler than the heating water at the bottom, so it sinks to the bottom, and the heating water rises.
  3. This repeats itself in a “circular circle” as long as the heat energy is being transfered.

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The lava lamp works just like the explanation above.

The last method of heat transfer is radiation. Unlike convection and conduction, it doesn’t need a medium to transfer heat through. Instead, it is done through electromagnetic waves, which is exactly how the sun transfers energy to Earth.

1 year ago
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