![]() Chloroplasts have a double membrane envelope composed of an outer membrane and an inner membrane. For plants, chloroplast-containing cells exist in the mesophyll. In all autotrophic eukaryotes, photosynthesis takes place inside an organelle called a chloroplast. Glucose, the primary energy source in cells, is made from two three-carbon GA3P molecules. In reality, the process includes many steps involving intermediate reactants and products. Figure: Chemical equation for photosynthesis: The basic equation for photosynthesis is deceptively simple. Before learning the details of how photoautotrophs convert light energy into chemical energy, it is important to become familiar with the structures involved. Though the equation looks simple, it is carried out through many complex steps. The energy from sunlight drives the reaction of carbon dioxide and water molecules to produce sugar and oxygen, as seen in the chemical equation for photosynthesis. Oxygen is generated as a waste product of photosynthesis. Figure: Photosynthesis: Photosynthesis uses solar energy, carbon dioxide, and water to produce energy-storing carbohydrates. Organisms break down these molecules to release energy for use in cellular work. ![]() These sugar molecules contain covalent bonds that store energy. It produces oxygen and glyceraldehyde-3-phosphate (G3P or GA3P), simple carbohydrate molecules that are high in energy and can subsequently be converted into glucose, sucrose, or other sugar molecules. Photosynthesis is a multi-step process that requires sunlight, carbon dioxide, and water as substrates. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License. We recommend using aĪuthors: Paul Flowers, Klaus Theopold, Richard Langley, William R. Use the information below to generate a citation. Then you must include on every digital page view the following attribution: If you are redistributing all or part of this book in a digital format, Then you must include on every physical page the following attribution: If you are redistributing all or part of this book in a print format, Want to cite, share, or modify this book? This book uses the If the molecular (or molar) mass of the substance is known, it may be divided by the empirical formula mass to yield the number of empirical formula units per molecule ( n): As the name suggests, an empirical formula mass is the sum of the average atomic masses of all the atoms represented in an empirical formula. Molecular formulas are derived by comparing the compound’s molecular or molar mass to its empirical formula mass. Molar mass can be measured by a number of experimental methods, many of which will be introduced in later chapters of this text. Molecular mass, for example, is often derived from the mass spectrum of the compound (see discussion of this technique in the previous chapter on atoms and molecules). These quantities may be determined experimentally by various measurement techniques. Determining the absolute numbers of atoms that compose a single molecule of a covalent compound requires knowledge of both its empirical formula and its molecular mass or molar mass. Recall that empirical formulas are symbols representing the relative numbers of a compound’s elements. The percent composition of this compound could be represented as follows: For example, consider a gaseous compound composed solely of carbon and hydrogen. The results of these measurements permit the calculation of the compound’s percent composition, defined as the percentage by mass of each element in the compound. When a compound’s formula is unknown, measuring the mass of each of its constituent elements is often the first step in the process of determining the formula experimentally. The elemental makeup of a compound defines its chemical identity, and chemical formulas are the most succinct way of representing this elemental makeup. But what if the chemical formula of a substance is unknown? In this section, these same principles will be applied to derive the chemical formulas of unknown substances from experimental mass measurements. Given the chemical formula of the substance, one may determine the amount of the substance (moles) from its mass, and vice versa. The previous section discussed the relationship between the bulk mass of a substance and the number of atoms or molecules it contains (moles). Determine the molecular formula of a compound.Determine the empirical formula of a compound.Compute the percent composition of a compound.By the end of this section, you will be able to:
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |