Schrödinger equation is the basic equation of wave mechanics which, for systems not dependent on time, takes the form:
where Ψ is the wavefunction, V is the potential energy expressed as a function of the spatial coordinates, E its total energy, 2 is the Laplacian operator, h is Planck’s constant, and m is the mass.
Second-order reaction is a reaction with a rate law that is proportional to either the concentration of a reactant squared, or the product of concentrations of two reactants.
For a general unimolecular reaction,
The reaction rate expression for a second order reaction is
If assumed that the concentration of reactant A is [A]o at t=0 and [A] at time T, the variables in the rate equation and integrate can be separated. The integrated rate law for a second-order reaction can be easily shown to be
1. Sediment is a fragmental material that originates from weathering of rocks and is transported by, suspended in, or deposited by water or air or is accumulated in beds by other natural agencies. When solidified, sediments form sedimentary rocks.
2. Strictly, sediment is a solid material that has settled down from a state of suspension in a liquid.
Sedimentary Rocks are formed by the accumulation and subsequent consolidation of sediments into various types of rock. There are three major types of sedimentary rocks:
Biogenic sedimentary rocks are formed from organic processes when organisms use materials dissolved in water to build a shell or other skeletal structure.
Clastic sedimentary rocks are composed directly of the sediments or fragments from other rocks.
Chemical sedimentary rocks are formed through evaporation of a chemical rich solution.
Based on their sizes, sediment particles are classified, based on their size, into six general categories:
Sedimentation is a process of separating specifically heavier, suspended matter, than the solution is. Solid matter settles on the bottom of the vessel and the liquid above it is poured off. The settling zone is the largest portion of the sedimentation basin. This zone provides the calm area necessary for the suspended particles to settle. The sludge zone, located at the bottom of the tank, provides a storage area for the sludge before it is removed for additional treatment or disposal.
Selenium was discovered by Jöns Jakob Berzelius (Sweden) in 1817. The origin of the name comes from the Greek word selene meaning moon. It is soft metalloid similar to sulfur. Ranges from grey metallic to red glassy appearance. Unaffected by water. Soluble in alkalis and nitric acid. Burns in air. Toxic by inhalation or ingestion. Selenium is obtained from lead, copper and nickel refining. Conducts electricity when struck by light. Light causes it to conduct electricity more easily. It is used in photoelectric cells, TV cameras, xerography machines and as a semiconductor in solar batteries and rectifiers. Also colours glass red.
Semiconductor is a material in which the highest occupied energy band (valence band) is completely filled with electrons at T = 0 K, and the energy gap to the next highest band (conduction band) ranges from 0 to 4 or 5 eV. With increasing temperature electrons are excited into the conduction band, leading to an increase in the electrical conductivity.
Most single bonds are sigma bonds (σ-bond). In the valence bond theory, a sigma bond is a valence bond that is symmetrical around the imaginary line between the bonded atoms.
Measurements are not infinitely accurate: we must estimate measurement uncertainty. The number of significant figures is all of the certain digits plus the first uncertain digit.
Rules for significant figures:
0.0023 | has two significant figures |
0.109 | has three significant figures |
2.00 | has three significant figures |
70 | has one significant figure |
In addition and subtraction, the number of significant figures in the answer depends on the original number in the calculation that has the fewest digits to the right of the decimal point.
In multiplication and division, the number of significant figures in a calculated result is determined by the original measurement that has the fewest number of significant digits.
In a logarithm of a number, keep as many digits to the right of the decimal point as there are significant figures in the original number.
In an antilogarithm of a number, keep as many digits as there are digits to the right of the decimal point in the original number.
Generalic, Eni. "Ledište." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
Glossary
Periodic Table