The Amazing World of Chemistry

Matter is all around us, actually every around us which has mass and takes up space is matter. Matter is also used loosely as a general term for the substance that makes up all observable physical objects. It has 2 properties, the Physical Properties and Chemical Properties. 

The Physical Properties of matter are the measurement of mass and other characteristics that can be seen without changing how that object looks. When you look at oranges, you know that they are oranges because of their color, shape, and smell. Mass, color, shape, volume, and density are some physical properties. The answers to the question about the present are physical properties. Density is an important physical property. Density is the mass of a substance per unit volume. Volume is the amount of space an object occupies. 

The Chemical Properties of matter however are those that can only be observed by changing the identity of the substance. A piece of paper burns and turns to a black substance. After the flame goes out you can no longer burn the new substance. The chemical properties have been changed. 

Matter is constantly changing. Ice in your soda melts, glass breaks and paper is ripped. When ice in your soda melts where does it go? What does it become? When you drop the ice cube into the liquid, it begins to melt because the temperature is higher than that of the ice cube. It's like putting a snowman on your front lawn in July. The ice cube becomes liquid water. This is an example of a physical change. The solid water turned to liquid water. It doesn't turn into soil or macaroni. It remains water. If it did change into soil or macaroni, your drink would taste terrible and you would have an example of a chemical change. Chemical changes are changing substances into other substances. If it could happen, ice changing into macaroni would be an example of a chemical change. A real example of a chemical change is spoiling milk or burning toast. Milk needs to be in the refrigerator or else it will go bad. If you've ever seen or smelled spoiled milk, it is not a pretty sight. The milk gets a sour odor and becomes lumpy. Unlike physical changes, you cannot reverse chemical changes. You can melt ice to get water and freeze that water to get ice again. You cannot make milk unspoiled.

Matter has five main states and they are Solids, liquids, gases, plasmas, and Bose-Einstein condensates. So, what is a solid? Solids are usually hard, because their molecules have been packed together. Solids can be hard, soft, big or small like grains of sand. The key is that the solids hold their shape and they don't flow like a liquid. A rock will always look like a rock unless something happens to it. The same goes for a diamond. Even when you grind up a solid into a powder, you will see tiny pieces of that solid under a microscope. Liquids will flow and fill up any shape of container. Solids like their shape. In the same way that a solid holds its shape, the atoms inside of a solid are not allowed to move around too much.

Liquids are an in-between state of matter. They can be found between the solid and gas states. They don't have to be made up of the same molecules. If you have a variety of materials dissolved in a liquid, it is called a solution. One characteristic of a liquid is that it will fill up the shape of a container. If you pour some water (H2O) in a cup, it will fill up the bottom of the cup first and then fill the rest. The water will also take the shape of the cup. The top part of a liquid will usually have a flat surface. That flat surface is the result of gravity pulling on the molecules. Putting an ice cube (solid) into a cup will leave you with a cube in the middle of the cup because it is a solid. The shape of the solid cube won't change until the ice becomes a liquid. 

Gas is everywhere. There is something called the atmosphere. That's a big layer of gas that surrounds the Earth. Gases are random groups of atoms. In solids, atoms and molecules are compact and close together. Liquids have atoms that are spread out a little more. Gases are really spread out and the atoms and molecules are full of energy. They are bouncing around constantly. Gases can fill a container of any size or shape. It doesn't even matter how big the container is. The molecules still spread out to fill the whole space equally. That is one of their physical characteristics. Think about a balloon. No matter what shape you make the balloon, it will be evenly filled with the gas molecules. The molecules are spread equally throughout the entire balloon. Liquids can only fill the bottom of the container, while gases can fill it entirely. The shape of liquids is really dependent on the force of gravity, while gases are light enough to have a little more freedom to move. 

Plasmas are a lot like gases, but the atoms are different, because they are made up of free electrons and ions of an element such as neon (Ne). You don't find naturally occurring plasmas too often when you walk around. They aren't things that happen regularly on Earth. If you have ever heard of the Northern Lights or ball lightning, you might know that those are types of plasmas. It takes a very special environment to keep plasmas going. They are different and unique from the other states of matter. Plasma is different from a gas, because it is made up of groups of positively and negatively charged particles. In neon gas, the electrons are all bound to the nucleus. In neon plasma, the electrons are free to move around the system. While natural plasmas aren't found around you that often, man-made plasmas are everywhere. Think about fluorescent light bulbs. They are not like regular light bulbs. Inside the long tube is a gas. Electricity flows through the tube when the light is turned on. The electricity acts as an energy source and charges up the gas. This charging and exciting of the atoms creates glowing plasma inside the bulb. The electricity helps to strip the gas molecules of their electrons. 

The Bose-Einstein state of matter was the only one created while your parents were alive. In 1995, two scientists, Cornell and Weiman, finally created the condensate. When you hear the word condensate, think about condensation and the way gas molecules come together and condense and to a liquid. The molecules get denser or packed closer together. Two other scientists, Satyendra Bose and Albert Einstein, had predicted it in the 1920s, but they didn't have the equipment and facilities to make it happen at that time. Now we do. If plasmas are super hot and super excited atoms, the atoms in a Bose-Einstein condensate (BEC) are total opposites. They are super unexcited and super cold atoms. 

Each of these states is also known as a phase. Elements and compounds can move from one phase to another when specific physical conditions are present. All matter can move from one state to another. It may require extreme temperatures or extreme pressures, but it can be done. Sometimes a substance doesn't want to change states. You have to use all of your tricks when that happens. To create a solid, you might have to decrease the temperature by a huge amount and then add pressure. Some of you know about liquid nitrogen (N2). It is nitrogen from the atmosphere in a liquid form and it has to be super cold to stay a liquid. What if you wanted to turn it into a solid but couldn't make it cold enough? You could increase the pressure to push those molecules together. The opposite works too. If you have a liquid at room temperature and you wanted a gas you could use a combination of high temperatures and low pressures to solve your problem. 

Phase changes happen when certain points are reached. Sometimes a liquid wants to become a solid. Scientists use something called a freezing point to measure the temperature at which a liquid turns into a solid. There are physical effects that can change the freezing point. Pressure is one of those effects. When the pressure surrounding a substance goes up, the freezing point and other special points also go up. That means it's easier to keep things solid at higher pressures. Just remember that there are some exceptions. Water (H2O) is special on many levels. It has more space between its molecules when it is frozen. There's a whole expanding effect when the molecules organize into a solid state. Generally, when temperatures get colder, solids shrink in size. They become denser. 

When you are a liquid and want to become a gas, you need to find a lot of energy. Once you can start to pump that energy into your molecules, they will start to vibrate. If they vibrate enough, they can escape the limitations of the liquid environment and become a gas. When you reach your boiling point, the molecules in your system have enough energy to become a gas. The reverse is true if you are a gas. You need to lose some energy from your very excited gas atoms. The easy answer is to lower the surrounding temperature. When the temperature drops, energy will be transferred out of your gas atoms into the colder environment. When you reach the temperature of the condensation point, you become a liquid. If you were steam over a boiling pot of water and you hit a wall, the wall would be so cool that you would quickly become a liquid. The wall absorbed some of your extra energy.