All About Chemistry

The Science of Snowflakes: Are Two Snowflakes the Same? Clouds are made up of water droplets, water vapour and suspended impurities such as tiny dust particles. If the temperature of the cloud then decreases the water molecules can begin to crystallise, arranging themselves around the dust particles in a hexagonal lattice structure known as Ice Ih (see figure 1). There are fourteen known forms of ice, but ice Ih, an abbreviation for "form 1 hexagonal", is stable between -100°C and 0°C and so it is the form seen in snowflakes. The hexagonally arranged water molecules stack in sheets with sides that are perfectly straight and angled at 120° to each other, called 'facets' (see figure 2). Figure 1 Red spheres represent oxygen atoms and white spheres represent hydrogen atoms. As the air is cooled, the closest neighbouring water molecules begin to arrange themselves into a lattice, gradually taking on the hexagonal geometry of '

The application of a scientific approach will be the challenge of teachers through the development of 7 activities of students that is observing, asking, trying, processing, tasting, reasoning, and creating. The dialogue :  On thursday morning chemistry class prepare the references to study about endothermic and exothermic reactions before the the teacher comes. *teacher enter the class* Teacher : Good morning everybody, in this morning we will discuss about exothermic and endothermic reactions. So who know the definition of endothermic and exothermic reactions? Student : *hand’s up* I know sir Teacher : Yes, please Student : An exothermic reaction gives off energy to the surroundings; like a fire giving off heat. An endothermic reaction takes in energy from the surroundings; like a snowman melting.  Teacher : Ok, that’s good. So exothermic reactions transfer energy to the surroundings, and this energy is usually heat energy, they cause the surroundings t

What is Acid Rain? Acid rain refers to a mixture of deposited material, both wet and dry, coming from the atmosphere containing more than normal amounts of nitric and sulfuric acids. Simply put, it means rain that is acidic in nature due to the presence of certain pollutans in the air  due to cars and industrial processes. It is easily defined as rain, fog, sleet or snow that has been made acidic by pollutants in the air as a result of fossil fuel and industrial combustions that mostly emits Nitrogen Oxides (NOx) and Sulfur Dioxide (SO2). Acidity is determined on the basis of the pH level of the water droplets. Normal rain water is slightly acidic with a pH range of 5.3-6.0, because carbon dioxide and water present in the air react together to form carbonic acid, which is a weak acid. When the pH level of rain water falls below this range, it becomes acid rain. When these gases react with water molecules and oxygen among other chemicals found in the atmosphere, mild acidic ch