The Physical and Chemical Properties of Matter

(a) Wax undergoes a physical change when solid wax is heated and forms liquid wax. (b) Steam condensing inside a cooking pot is a physical change, as water vapor is changed into liquid water. (credit a: modification of work by “95jb14”/Wikimedia Commons; credit b: modification of work by “mjneuby”/Flickr) OpenStax Chemistry 2e The characteristics that … Continue reading The Physical and Chemical Properties of Matter

Reading the Chemical Hazard Diamond or Fire Diamond

The National Fire Protection Agency (NFPA) hazard diamond summarizes the major hazards of a chemical substance. Source: OpenStax Chemistry 2e OpenStax Chemistry 2e You may have seen the symbol shown in the image above on containers of chemicals in a laboratory or workplace. Sometimes called a “fire diamond” or “hazard diamond,” this chemical hazard diamond provides … Continue reading Reading the Chemical Hazard Diamond or Fire Diamond

Separation of Hydrogen and Oxygen from Water

The decomposition of water is shown at the macroscopic, microscopic, and symbolic levels. The battery provides an electric current (microscopic) that decomposes water. At the macroscopic level, the liquid separates into the gases hydrogen (on the left) and oxygen (on the right). Symbolically, this change is presented by showing how liquid H2O separates into H2 and … Continue reading Separation of Hydrogen and Oxygen from Water

What are Atoms and Molecules?

(a) This photograph shows a gold nugget. (b) A scanning-tunneling microscope (STM) can generate views of the surfaces of solids, such as this image of a gold crystal. Each sphere represents one gold atom. (credit a: modification of work by United States Geological Survey; credit b: modification of work by “Erwinrossen”/Wikimedia Commons) OpenStax Chemistry 2e … Continue reading What are Atoms and Molecules?

The Classification of Matter: Mixtures and Pure Compounds

(a) The compound mercury(II) oxide, (b) when heated, (c) decomposes into silvery droplets of liquid mercury and invisible oxygen gas. (credit: modification of work by Paul Flowers) OpenStax Chemistry 2e Matter can be classified into several categories. Two broad categories are mixtures and pure substances. A pure substance has a constant composition. All specimens of a pure … Continue reading The Classification of Matter: Mixtures and Pure Compounds

The Domains of Chemistry

(a) Moisture in the air, icebergs, and the ocean represent water in the macroscopic domain. (b) At the molecular level (microscopic domain), gas molecules are far apart and disorganized, solid water molecules are close together and organized, and liquid molecules are close together and disorganized. (c) The formula H2O symbolizes water, and (g), (s), and … Continue reading The Domains of Chemistry

Chemistry: The Central Science

Knowledge of chemistry is central to understanding a wide range of scientific disciplines. This diagram shows just some of the interrelationships between chemistry and other fields. Source: OpenStax Chemistry 2e OpenStax Chemistry 2e Chemistry is sometimes referred to as “the central science” due to its interconnectedness with a vast array of other STEM disciplines (STEM … Continue reading Chemistry: The Central Science

The Scientific Method of Chemistry

The scientific method follows a process similar to the one shown in this diagram. All the key components are shown, in roughly the right order. Scientific progress is seldom neat and clean: It requires open inquiry and the reworking of questions and ideas in response to findings. Source: OpenStax Chemistry 2e OpenStax Chemistry 2e Chemistry … Continue reading The Scientific Method of Chemistry

Changing Human Behavior

Source: By Nabokov (talk) Required photo citation:- "Photo by Tom Oates, 2008" (Transfered byBhagyaMani/Original uploaded by Nabokov) - I created this work entirely by myself. (Original uploaded on en.wikipedia), CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11805665 OpenStax Biology 2e Legislation throughout the world has been enacted to protect species. The legislation includes international treaties as well as national … Continue reading Changing Human Behavior