Postagens

Bases

Imagem
NaOH  à  Na +   + OH - The blue color indicates that the paper is in an acid medium. Bases are compounds capable of dissociating in aqueous media releasing ions, of which a single anion is OH-. *  Form electrolytic solutions (conduct electricity). Ex: NaOH, KOH, NH4 OH *  React with acids by neutralizing reactions and generate salt and water as products. Ex: H2SO4 + 2NaOH  à  Na2 SO4 + 2H2O *  Act as acid-base indicators. Bases are also important for pH reading, solutions with pH higher than 7 are basic. There are several acid-base indicators to identify if the compound is basic, the most commonly used is litmus, but there are others that can also be used. As for force, the bases are determined from their degree of dissociation, for strong bases (value greater than 5%), for weak (value equal to or less than 5%). LENZI, Ervim, Química Geral Experimental, 2.ed. Rio de Janeiro: F. Bastos, 2012 CHRISTOFF, Paulo,...
Postar um comentário
Leia mais

Solutions

Imagem
Cs: 36g of NaCl in 100ml of H2o the    20°c Unsaturated 100ml of de H2o with    20g of NaCl Saturated 100ml of de H2o with    36g of NaCl Supersaturated à   100ml of H20 with 37g of NaCl, is heated to dissolves the  bottom body  Solutions studied in chemistry are homogeneous, formed by a product and solvent. The solute dissolves the solvent is in largest amount and will act dissolving the solution. The solution can be liquid, solid or gas. Another way to sort the solutions in about this aspect, we have three types of solutions: Unsaturated : when the amount of solute is less  than it can be dissolved. Saturated : when the amount of solute is equal to that which can be dissolved without having a bottom body. Supersaturated : when the amount of solute is greater than it can be dissolved, bt without a bottom body, as the bottom body dissolved after the solution is heated. referencia ...
Postar um comentário
Leia mais

Periodic table

Imagem
The elements were organized by the professor of the University of St Petersburg, Dimitri Ivanovich Mendeleev, who wrote a book about the chemical elements, were about 63 elements, and Mendeleev organized them by function of the mass of their atoms establishing families and groups. The elements in the table are organized horizontally, in numerical sequence, according to their atomic numbers, and are organized through periods and families. There are seven periods in the table and the amount of electronic layers that the chemical elements present is indicated by the period number, they represent the horizontal rows of the table.  References: Periodic table families. Link: http://www.tabelaperiodicacompleta.com/familias-da-tabela-periodica, 2017. Access on March 13, 2017.
Postar um comentário
Leia mais

Isotopes

Imagem
Isotopes are two or more atoms of the same chemical element with equal atomic numbers and mass numbers. The difference between them is found in the number of neutrons. Isotopes can differ into some characteristics, such as density and its applicability, as in medicine, industry and scientific research. In medicine, an example of a radioisotope is iodine-131 that is used in the treatment of thyroid cancer because it accumulates in this organ, its gamma radiations destroy the cancer cells.   Reference: MARTINELLI, LUIZA. Unraveling Environmental Issues with Stable Isotopes. 1st Edition, Brazil: Editora Oficina de textos, 2009. 144p.
Postar um comentário
Leia mais

Photosynthesis

Imagem
Chemical Reaction:6 CO 2 + 6 H 2 0 => C 6 H 12 O 6 + 6 H 2 O The chemical reaction that basically occurs in photosynthesis is that the plant captures sunlight through the pigments in the leaves, absorbs water and minerals from the Earth by the root of the plant and also absorbs the carbon dioxide from the air, passing through a chemical reaction, releasing the oxygen we breathe, and producing the sugar that is its food. References:  Fogaça, J.   Chemical Reaction of Photosynthesis. Website: http://brasilescola.uol.com.br/quimica/reacao-quimica-envolvida-na-fotossintese.htm , 2017. Access on March 13, 2017.
Postar um comentário
Leia mais

Atoms

Imagem
Atoms are the basic units of matter and the defining structure of elements. Atoms are made up of important particles :  Protons ( positive particles ), neutorns (neural particles ) ,  electrons (negative particles),  and the small dense region consisting of protons and neurons at the center of an atom,  called nucleus .        Reference -  What is  an atom, Disponivel em www.livescience.com/37206-atom-definition.html , acesso 2017 .
Postar um comentário
Leia mais

Molecule

Imagem
molecule may beunderstoood as characteriting a substence which is formed of at least tow atoms, the same or different. Thus ,the  molecules is necessarily the presence of tow atoms or more , they are electical elements contraning a grup of atoms where thsy must be connected to each other due to the type of band, which is covalent or ionic.c The molecule isin constant motion, a phenomenon known as molecular vibratios . Held together by the fact that they share electrons . In te covalents , the electron trnasfers in the ionic bonds. Reference - 1° Edição . Definição molecular. Link:https://www.significadosbr.com.br/molecular, 2015. Acesso em 17 de março de 2017 
Postar um comentário
Leia mais