Environmental chemistry

Introduction: Many chemical compounds are broken down into two very distinct categories: acidic or basic. Acidic, based on the Bronsted-Lowry Theory, is defined as a proton (H+) donor. An equation exemplifying an acid dissolving in water is: HCl (g) H2O H+ (aq) + Cl- (aq) A base, based on the Bronsted-Lowry Theory, is defined as a proton (H+) acceptor. An equation exemplifying a base dissolving in water: NaOH (s) H2O Na+ (aq) + OH- (aq) Molarity, also known as the concentration…

Levofloxacin cocrystals were prepared by solvent evaporation method. The drug and co formers, stearic acid and sodium saccharin were physically mixed in varying ratios of 1:1, 1:3, 1:5, 1:7 and 1:1 and 2:1 respectively in a glass mortar and the mixtures were dissolved in ethanol as solvent for crystallization. The solvent evaporation was carried in rotary flash evaporator (Laborota 4000, Hiedolph) maintained at 40 ± 2ºC and speed of 30 rpm. The products obtained were dried in a desiccator and…

Analyzing Various Permeable Bags Placed in Different Concentrations of Water and Sucrose Introduction Osmosis is defined as the movement of water from a region of water that has a higher potential to a region of water that has a lower potential through semipermeable membranes. There are three types of solutions, hypertonic, hypotonic, and isotonic. Hypertonic solutions have a higher concentration of solute while hypotonic solutions have a lower concentration of solute. Isotonic solutions have…

Chemicals Congo red (CR) an anionic dye (C32H22N6Na2O6S2 and Molar Mass as 696.7 gmol-1) used in the present work (Fig.1a) and zinc acetate dihydrate were purchased from LOBA Chemie Company, India. Methylene blue (MB) a cationic dye (C16H18N3SCl and Molar Mass of 319.85 gmol-1) as shown in Fig.1b, was purchased from Oxford laboratory reagent Co. Zinc acetate used for the preparation of nanoparticles ZnO and sodium hydroxide were purchased from Biotech laboratory chemicals company. Ethyl alcohol…

A small burette funnel was filled with column packing solvent at mobile phase, high boiling petroleum, in this case hexane (and then 10%acetone hexane mixture), and Alumina as stationary phase. When adding the sand and the alumina they have to be first mixed with the hexanes in order not to disturb the column. The Lycopene is Red- Orange and more attracted to alumina due to its high degree of Unsaturation, which can be expected to be eluted after Yellow-Orange Carotene pigments. And the other…

Marcel Duchamp | Fountain “All in all, the creative act is not performed by the artist alone; the spectator brings the work in contact with the external world by deciphering and interpreting its inner qualification ..” Do you know, which artist could have said this? That was a citation of Marcel Duchamp, one of the most important artists of the 20th century. In the next few minutes I will give you some informations about the person, who said this quite interesting words. Duchamp‘s life…

Nucleophilic Acyl Substitution: The Synthesis of Esters Razon, Valjean Paulo Mella Rico, Fatima Sarah Rogel Institute of Chemistry, University of the Philippines, Diliman, Quezon City 1101 Philippines…

7.59 From the stress–strain data for poly(methyl methacrylate) shown in Figure 7.24, determine the modulus of elasticity and tensile strength at room temperature [20°C (68°F)], and compare these values with those given in Tables 7.1 and 7.2. Solution From Figure 7.24, the elastic modulus is the slope in the elastic linear region of the 20C curve, which is The value range cited in Table 7.1 is 2.24 to 3.24 GPa (325,000 to 470,000 psi). Thus, the plotted value is a little on the…

Introduction Enzymes, which speed up a chemical reaction without being consumed or changing the products of the reaction, are very important because they control the cellular activity of all living organisms. Enzymes are also described as being “catalysts”. In biological systems, specific enzymes catalyze particular cellular reactions. Each enzyme has a unique 3-D shape, and this shape determines which reaction it catalyzes. However, in order for a chemical reaction to move forward, an energy…

A weakness in this experimental design is the manual dilution of the Aquasol concentrations. This is because, if a random error were to occur, and the diluted Aquasol concentration does not result in the desired concentration, the validity, reliability, and precision of the results is majorly decreased. Whereas if the Aquasol concentrations were already previously diluted in a lab by professionals, or were bought in the correct concentrations, the reliability, validity, and precision of the…