SOL 5.4 a,b,c, October, 2012
Matter
All matter, regardless of shape, size, or color, is made up of particles that are too small to be seen with the human eye. These particles are called atoms and molecules.
An element is a type of matter that is made up of atoms. An atom is the smallest unit of matter. All of the atoms in an element are alike. Elements are pure substances that cannot be broken down or separated into simpler substances. All atoms have three main parts: protons, neutrons, and electrons. The protons and neutrons are found in the nucleus of the atom. The nucleus is located in the center of the atom. The electrons circle around the nucleus in the electron cloud. Protons are positively charged. Electrons are negatively charged. Neutrons have no charge, they are neutral.
Another type of matter is called a compound. Most kinds of matter found on the earth are compounds. A compound is formed when two or more elements join together. The smallest particle found in a compound is a molecule. A molecule is made up of two or more unlike atomsthat are linked together. Water is an example of a compound. Two hydrogen (H) atoms join with one atom of oxygen (O) to form a molecule of water (H20). Table salt is another example of a compound. One atom of sodium (Na) joins with one atom of chlorine (Cl) to form table salt (NaCl).
The three states of matter are solid, liquid, and gas.
A solid has a definite shape and size.
A liquid has no definite shape, but has volume. A liquid takes on the shape of the container it happens to be in.
A gas also has no definite shape, size, or color. A gas cannot be seen. A gas takes on the shape of the container it happens to be and can fill up all available space in that container.
Each state of matter can change from one to another; for example, a solid can change to a liquid, which then can change into a gas. These are called phase changes. Examples of these changes are: melting – a solid changing into a liquid, freezing – a liquid changing into a solid, vaporization – a liquid changing into a gas, condensation – a gas changing into a liquid.
Mixtures and Solutions
A mixture is formed is when two or more substances are blended together physically. This means they do not lose their identifying features; they can still be recognized and named even though they are part of a mixture. A good example is when different coins are mixed in a glass jar. Even though they are mixed together, each coin can still be identified; dimes are still dimes, pennies are still pennies, nickels are still nickels, and quarters are still quarters. Other examples of mixtures are oil and water, chicken noodle soup, and salad.
A solution is a kind of mixture. A solution is when one substance dissolves into the other. This means that the substance that is being dissolved loses its identifying feature. It cannot return to its original state. A good example of a solution is sugar water. When the sugar is stirred into the water, it disappears, or becomes invisible; however the sugar is still there. In a solution the substances are mixed evenly throughout. Other examples of solutions are Kool-aid, Tea, coffee, Nestle’s chocolate milk, and hot cocoa mix.
Remember: All solutions are mixtures, but not all mixtures are solution.
There are two parts to a solution; the solute and the solvent. The solute is the substance that is being dissolved and the solvent is the substance doing the dissolving. For example, in the sugar water solution, the sugar is the solute and the water is the solvent.
States of Matter
Everything on earth is made of matter. All matter is made of tiny particles called atoms, which are always in motion. The three states of matter are solid, liquid, and gas. Depending on how fast or slow these atoms move determines the state of matter.
In a solid, the atoms are packed tightly together which restricts their movement. In fact they simply vibrate back and forth which allows them to hold their shape. A pencil is an example of a solid.
In a liquid, the atoms are placed farther apart and actually begin to move somewhat faster. The atoms are able to slip past each other. Because of this, liquids cannot hold their shape. They take the shape of the container in which they are placed. Milk is an example of a liquid.
In a gas, the atoms move very quickly and move away from each other. They cannot hold their shape and fill up the space of the container in which they are placed. A good example of a gas is air freshener. When sprayed into a room, the atoms in the aerosol spray go out into the room, filling up the space and going further into other rooms. This explains how fast the atoms in a gas can travel to fill up the space in which they are placed.
Temperatures can cause the states of matter to change from one to another. Solids can change to liquids, which then can change to a gas.
SOLID LIQUID GAS
When temperatures decrease, the atoms in a liquid begin to slow down; the atoms are barely moving. This process is called freezing which causes the liquid to change into a solid. When temperatures increase, the atoms begin to move faster and more freely and actually slip past each other; this process is called melting which causes the solid to change into a liquid. When the temperatures continue to rise; the atoms in the liquid move faster and away from each other. This process is called vaporization or evaporation. This causes the liquid to change into a gas. The process by which a gas changes to a liquid is called condensation. An example of condensation is the steam from a shower leaving water droplets on a mirror.
An example of states of matter changing from one to another is water. Water, in a liquid state, can freeze into an ice cube (liquid in a solid state). Then, when temperatures increase, the ice cube melts, turning the ice cube (solid) into a liquid. When temperatures continue to increase, such as boiling water on a stove, the liquid then changes into steam, which is a gas.