Physical & Chemical Properties

 Physical & Chemical Properties

Why is density not a chemical property?

Density is not a chemical property; it is a physical property. Density is the measure of the mass of a substance divided by its volume. It is a measurable property that does not change the identity of the substance when determining it.

What are examples of chemical properties?

Chemical properties are the properties of a specific type of matter that occur when the matter goes through chemical changes. Chemical properties/changes result in a change in the composition of the matter. Examples include corrosion and reactivity.

What are examples of physical properties?

Physical properties are characteristics of a certain type of matter that can be observed and/or measured. Physical properties do not affect the chemical composition of the matter. Examples of physical properties include color, mass, texture and density.

Matter is defined as anything that has mass and takes up space. All types of matter have certain properties that are unique to that matter. These properties can be divided into two separate categories: physical properties and chemical properties.

What are the Physical Properties of Matter?

The physical property definition is the properties of matter are generally things that describe the property with visual inspection or taking some kind of measurement. For example, three of the physical properties of matter are length, volume, and mass. There is no change to the chemical composition of a substance when examining its physical properties. Visual observation, a balance, a ruler, or another method of measurement, can be used to determine physical properties. None of the methods used will have any effect on the chemical composition of a substance.

Some additional physical properties examples are:

Color

Texture

Shape

Density

Matter will sometimes undergo physical changes. This happens when a particular type of matter changes state from solid to liquid, liquid to gas, gas to liquid, liquid to solid, or even solid to gas. These phase changes, known as melting, freezing, vaporization, condensation, and sublimation, have no effect on the chemical composition of the substance, therefore, they are not chemical changes. Phase changes, or changes of state, occur when energy is added to or taken from the substance.

For example, an ice cube left on a counter will absorb heat energy from its surroundings and eventually melt to become liquid water. In both the solid state and liquid state, it is still water. No chemical reaction occurred to change the identity of the substance. However, sometimes the physical properties change during a phase change. An ice cube may have a square shape, but when it melts to become a puddle of liquid water, it most definitely takes a different shape. Both shapes are still water.

The physical and chemical properties of matter depend solely on the type of matter in question. Matter can be living or non-living. It can be organic (containing carbon) or inorganic (no carbon present). Essentially, everything is matter; from the tiniest insect to the largest tree. Humans, animals, cars, houses, grass, and food are all types of matter in everyday life.///

Color as a Physical Property

Color is an observable characteristic of matter, therefore, color is a physical property, not a chemical property. Color is observed as the portion of the visible electromagnetic spectrum that is reflected by the substance. If an apple is red, it is because the matter that makes up the apple absorbs all visible colors except red. That makes it appear red to the person observing it. The grass is green because the green wavelengths are reflected and not absorbed.

pH as a Chemical Property

pH is a chemical property that is determined by how many H+ ions are released from a type of matter when it is dissolved in water. Substances that release many free H+ ions are considered to be acidic. Substances that break down in water and produce OH- ions are considered to be bases.

pH is the measure of how many H+ ions are present in terms of concentration. The higher the concentration of H+, the more acidic the solution is. The lower the concentration of H+ and the higher the concentration of OH-, the more basic it is. This makes pH a chemical property because it depends on how a solid or liquid substance interacts with water when mixed together.

The pH scale runs from 0-14. Matter with a pH of 7, like pure water is considered to be neutral. Anything that has a pH of 0 up to 7 is acidic and anything above 7 and up to 14 is basic.

Stomach acid is a strong acid at a pH of about 2. Soaps and detergents are more basic with a pH around 8, depending on the product.