Water and Mineral Salts in Living Organisms
Water: The Essence of Life
Properties of Water
Water, the most abundant molecule in living matter, comprises 20% to 85% of an organism’s mass, decreasing with age. A water molecule consists of two hydrogen atoms and one oxygen atom, covalently bonded at a 104.5° angle. Although electrically neutral, the atoms have different electronegativity values, giving water its polar character. This polarity allows water molecules to form hydrogen bonds with each other.
- Dielectric Constant: The force with which
Thermodynamics, Metallurgy, and Coordination Chemistry
Some basic concepts of thermodynamics help us in understanding the theory of metallurgical transformations. Gibbs energy is the most significant term here. The change in Gibbs energy, ΔG for any process at any specified temperature, is described by the equation: ΔG = ΔH – TΔS
where, ΔH is the enthalpy change and ΔS is the entropy change for the process. For any reaction, this change could also be explained through the equation: ΔG = – RTlnK
where, K is the equilibrium constant of the ‘reactant
Read MorePhotosynthesis, Trophic Networks, and Separation Methods
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially by using the energy from sunlight.[1] Photosynthesis occurs in plants.
Trophic Networks
A trophic network is the set of food chains in an ecosystem. That is, it is the expression of all the food relationships within an ecosystem, a way of representing how matter and energy circulate among its members.
Stimulus
We call stimulus the changes that occur in the environment or inside an organism
Read MoreMetallurgy Terms: Blowholes, Hardenability, and More
Metallurgy Terms
Blowholes
Blowholes are cavities formed when gases dissolved in an alloy are trapped during solidification.
Hardenability
Hardenability is the ability of a material to be tempered.
Carburetion
Carburetion is the process of combining carbon and iron to make steel.
Esteadite
Esteadite is a type of eutectic melting, hard and brittle, with a melting temperature of 960°C. In foundries, it appears gray.
Diffusion
Diffusion is the movement of atoms in a disordered lattice from their equilibrium
Read MoreBiology Questions and Answers: Chapters 1-3
Chapter 1
- Life is organized in a hierarchical fashion. Which of the following sequences correctly lists that hierarchy as it increases in complexity?
D) molecule, cell, tissue, organ, organ system, organism, population, community, ecosystem - Which of the following statements about genetics is true?
B) Each organism has its own unique DNA code. - Organisms that are prokaryotes are in the domains
A) Bacteria and Archaea. - Which of the following statements about the domain Bacteria is true?
D) All bacteria
Understanding Matter: Pure Substances, Mixtures, and Solutions
Matter: Pure Substances and Mixtures
Pure substances have a constant composition that does not change under any physical conditions. They cannot be broken down into simpler substances by physical means.
Pure Substances: Compounds and Elements
- Compounds: Pure substances that can be broken down into simpler substances through chemical processes.
- Elements: Pure substances that cannot be broken down into simpler substances by any means.
Mixtures
Mixtures are combinations of multiple pure substances that can
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