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. Chemical changes are also known as chemical reactions. If a chemical change or reaction occurs, the observed characteristics are chemical properties. The two classes of physical properties are intensive and extensive properties:. Examples of physical properties include mass, density, color, boiling point, temperature, and volume.
Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. In the liquid phase, the particles of a substance have more kinetic energy than those in a solid. The liquid particles are not held in a regular arrangement, but are still very close to each other so liquids have a definite volume.
Liquids, like solids, cannot be compressed this property is useful in hydraulics. Particles of a liquid flow around each other, so liquids have an indefinite shape—a liquid will change shape to conform to its container. Force is spread evenly throughout the liquid, so when an object is placed in a liquid, the liquid particles are displaced by the object.
Gases are everywhere. Solid molecules are tightly compacted together, liquid molecules are less organized and more spread out, while gas molecules are very spread out and disorganized. Gas molecules fill up any container with no consideration to size or shape. Gas particles have a great deal of space between them and have high kinetic energy. If unconfined, the particles of a gas will spread out indefinitely; if confined, the gas will completely fill its container.
When a gas is put under pressure by reducing the volume of the container or pumping the gas into a container, the space between particles is reduced and the pressure exerted by their collisions increases.
If the volume of the container is held constant, but the temperature of the gas increases, then the pressure will also increase.
Conversely, if the pressure is decreased, the temperature will also decrease you have probably observed this as you spray a can of compressed air and it gets cold. If compressed enough, the molecules may form a liquid for example, compressed propane is a liquid, but as it is released from the tank it changes back to a gas. For example, density is an intensive property because it is the same no matter where you sample a substance.
Other intensive properties include boiling point, freezing point, viscosity, luster, and state of matter. In contrast, an extensive property does depend on the amount of matter in a sample.
For example, mass depends on sample size. Other examples of extensive properties include length, volume, area, and thermodynamic properties such as enthalpy and entropy.
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