You will see similar models throughout this book. Google Form: Atoms and Molecules. Website 1: Jefferson Lab. Website 2: Build Molecules. Virtual Molecule Lab. Molecule Basics Top of Page. Build a Molecule Top of Page.
How does thermal energy affect particles? Matter exists in different states depending on how the molecules are arranged. Molecules are in constant contact with each other in a liquid. In a gas, the molecules are widely spaced apart yet can collide with each other. In a solid, the atoms are closely spaced together and vibrate in position. Changes of states of matter happen when the temperature or pressure on the molecules changes. Interactive Link1.
Interactive Link 2. Virtual Lab. States of Matter Top of Page. These three forms of matter are called the states of matter. There are two types of mixtures : Heterogeneous and Homogeneous. Some of the physical properties of substances include their: Changing states without altering or changing the identity of the substance. Boiling point. Melting point. Heat capacity. In addition to that, it is important to understand why all liquids are not the same, and why some are purer than others, in terms of their chemical makeup or compositions.
This is why the classification of matter is important. They are all water, but the chemical compositions may be very different. The five phases of matter. There are four natural states of matter : Solids, liquids, gases and plasma. The fifth state is the man-made Bose-Einstein condensates. In a solid, particles are packed tightly together so they don't move much.
A chemical property is a characteristic of a substance that may be observed when it participates in a chemical reaction. Examples of chemical properties include flammability, toxicity, chemical stability, and heat of combustion. There are two types of pure substances that are Elements and Compounds. Examples of elements are: Iron, Silver, Gold, Mercury etc.
Examples of compounds are: Water, Carbon dioxide, methane, vinegar etc. A chemical property cannot be established just from touching or looking at the substance. There must be a chemical change to see it! Some examples are: flammability, pH , and reactivity with water or acid. This is an example of a chemical property. A solution is a homogeneous mixture of two or more substances. Gordon Furman University.
Learning Objectives Use physical and chemical properties, including phase, to describe matter. Distinguish between physical and chemical changes.
Recognize physical methods used to separate mixtures. Physical and Chemical Properties The properties that chemists use to describe matter fall into two general categories. Image courtesy of Elizabeth R. Elements and Compounds Any sample of matter that has the same physical and chemical properties throughout the sample is called a substance. An environmentalist might consider water "pure" even if it contains the normal amount of dissolved oxygen and carbon dioxide, but no other "pollutants".
To a chemist, water containing oxygen is no longer a pure substance, but a mixture. In pure water, the ratio of hydrogen to oxygen atoms is always Inorganic and Organic Compounds Compounds can be further classified as being inorganic or organic. Organic structures The two molecules shown below are heavily used in the pharmaceutical industry.
Mixtures A material composed of two or more substances is a mixture. Saltwater is a homogeneous mixture, or a solution. Soil is composed of small pieces of a variety of materials, so it is a heterogeneous mixture.
Water is a substance; more specifically, because water is composed of hydrogen and oxygen, it is a compound. Oxygen, a substance, is an element. Answer b Hydrogen is an element. It can be located on the periodic table. Answer c An egg assume raw would be a heterogeneous mixture. Phases Another way to classify matter is to describe it as a solid, a liquid, or a gas, which was done in the examples of solutions.
When liquid water boils to make gaseous water, it undergoes a phase change. Matter can be classified in a variety of ways, depending on its properties. What is the difference between a heterogeneous mixture and a homogeneous mixture? Here are several examples of chemical properties:. There are two types of change in matter: physical change and chemical change. Many physical changes are reversible such as heating and cooling , whereas chemical changes are often irreversible or only reversible with an additional chemical change.
Physical change : Blending a smoothie involves physical changes but no chemical changes. Another way to think about this is that a physical change does not cause a substance to become a fundamentally different substance but a chemical change causes a substance to change into something chemically new. Blending a smoothie, for example, involves two physical changes: the change in shape of each fruit and the mixing together of many different pieces of fruit. Because none of the chemicals in the smoothie components are changed during blending the water and vitamins from the fruit are unchanged, for example , we know that no chemical changes are involved.
Cutting, tearing, shattering, grinding, and mixing are further types of physical changes because they change the form but not the composition of a material. For example, mixing salt and pepper creates a new substance without changing the chemical makeup of either component. Phase changes are changes that occur when substances are melted, frozen, boiled, condensed, sublimated, or deposited. They are also physical changes because they do not change the nature of the substance. Boiling water : Boiling water is an example of a physical change and not a chemical change because the water vapor still has the same molecular structure as liquid water H 2 O.
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