An atomic mass (symbol: "m") is the mass of a single atom of a chemical element. It includes the masses of the 3 subatomic particles that make up an atom: protons, neutrons and electrons.
Atomic mass can be expressed in grams. However, because each atom has a very small mass, this is not very helpful. Instead, atomic mass is expressed in unified atomic mass units (unit symbol: u). 1 atomic mass unit is defined as 1/12 of the mass of a single carbon-12 atom. 1 u has a value of 1.660 539 066 60(50) × 10 kg.
A carbon-12 atom has a mass of 12 u. Because electrons are so light, we can say that the mass of a carbon-12 atom is made of 6 protons and 6 neutrons. Because the masses of protons and neutrons are almost exactly the same, we can say that both protons and neutrons have a mass of roughly 1 u. Hence, we can get a rough value of an atom's mass in atomic mass units by working out the sum of the number of protons and the number of neutrons in the nucleus, which is called the mass number. The atomic mass of an atom is usually within 0.1 u of the mass number.
The number of protons an atom has determines what element it is. However, most elements in nature consist of atoms with different numbers of neutrons. An atom of an element with a certain number of neutrons is called an isotope. For example, the element chlorine has two common isotopes: chlorine-35 and chlorine-37. Both isotopes of chlorine have 17 protons, but chlorine-37 has 20 neutrons, 2 more neutrons than chlorine-35, which has 18. Each isotope has its own atomic mass, called its isotopic mass. In the case of chlorine, chlorine-35 has a mass of around 35 u, and chlorine-37 around 37 u.
As mentioned above, note that the atomic mass of an atom is not the same as its mass number. The mass number (symbol: A) of an atom is the sum of the number of protons and the number of neutrons in the nucleus. Mass numbers are always whole numbers with no units. Also, "relative" isotopic mass is not the same as isotopic mass, and relative atomic mass (also called "atomic weight") is not the same as atomic mass.
A relative isotopic mass is the mass of an isotope relative to 1/12 of the mass of a carbon-12 atom. In other words, a relative isotopic mass tells you the number of times an isotope of an element is heavier than one-twelfth of an atom of carbon-12. The word "relative" in relative isotopic mass refers to this scaling relative to carbon-12. Relative isotopic mass is similar to isotopic mass and has exactly the same numerical value as isotopic mass, whenever isotopic mass is expressed in atomic mass units. However, unlike isotopic mass, relative isotopic mass values have no units.
Like relative isotopic mass, a relative atomic mass (symbol: "A") is a ratio with no units. A relative atomic mass is the ratio of the average mass per atom of an element from a given sample to 1/12 the mass of a carbon-12 atom. We find the relative atomic mass of a sample of an element by working out the abundance-weighted mean of the relative isotopic masses. For example, to continue the chlorine example from above, if there is 75% of chlorine-35 and 25% of chlorine-37 in a sample of chlorine,
Price
There are different definitions of price. Perhaps the simplest definition is to say "price is the value of a product (good) or service". A price is expressed in other goods, services, or in money.
Here is an example about price: Peter raises sheep for their wool. Sally raises chickens for their eggs. Winter is coming, so Sally wants to make a warm wool coat.
She first measures how much wool she needs for a coat. She thinks she needs the wool from 2 sheep for the coat. She then goes to Peter and asks him what he wants for the wool she needs. Peter then tells her the price he is asking for his wool. Sally might trade some of her chicken eggs for the wool.
Sometimes trading eggs for wool is difficult. So people invented something they called "money". This is cash or currency used for trading.
If Peter does not need eggs, he will not trade his wool for eggs. The price for his wool "in eggs" is zero, but Peter does need something else. So Sally goes to a market and sells some of her eggs for money. Then she goes to Peter and gives him money for the wool. How much money Peter wants for his wool is the price.
Doping
Doping or dope can mean:
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Gaza Strip
The Gaza Strip is a self-governing stretch of land along the Mediterranean. The main city in the Gaza Strip is called Gaza. The strip is currently governed by Hamas, a group declared as terrorists by many western nations for its launching of rockets into Israel.
The territory is 41 kilometers (25 mi) long, and from 6 to 12 kilometers (3.7 to 7.5 mi) wide, with a total area of 365 square kilometers (141 sq mi). About 1.8 million Palestinians live on a surface of roughly 360 km², making Gaza the 3rd most densely populated area on Earth.
Gaza was formed in 1967 when Israel moved Jewish settlements and troops into Gaza. Israel controlled the Strip's borders, coastline and airspace until 2005, when it withdrew. An election was held in January 2006, which Hamas won. Since then, Israel has conducted several wars with Hamas due to alleged terrorist acts, causing much of the infrastructure of Gaza to be non functional. It has been placed under an Israeli and U.S.-led international economic and political boycott since 2006.
Unemployment
Unemployment or joblessness is when a person who is of normal working age (usually about 15-18 to about 60-65) does not have a paid job. They therefore do not get paid a salary. In some parts of the world, there are social networks to care for the unemployed.
The unemployment rate is the number of unemployed people divided by the total population of that age group of a country. The unemployment rate is influenced by many things, including the government of a country to the average age of a country's population. Unemployment is a bad thing for society.
A certain amount of unemployment is natural. 'Full employment' does not mean no-one is out of work. Governments now aim to increase the number of jobs (which can be done) rather than cut out all unemployment (which cannot be done).
People with Autism and other mental disabilities are mistreated in the workplace, leading to only around 15% of autistic people being employed at all.
Salary
A salary is a type of payment a person gets for work done for a job. A "salary" is usually paid for a fixed period of time, such as a month or a week. Generally, it does not matter how many hours are worked, the salary remains the same. If someone is not a salaried employee, they are generally an "hourly" employee and are paid a certain amount for each hour's which is known as "wages."
Instant noodles
Instant noodles are a product used in cooking - a type of pre-cooked noodle. These noodles are cooked at the factory and packaged as dried noodles, often with a special powder that adds flavor to the noodles. The dish is prepared very quickly (usually 5 minutes or less), simply by putting the noodles together in hot water and then adding the powder. A kind of noodle soup is then ready to eat.
"Instant noodles" are very popular in Asia, and among many students and poorer people, because they are very cheap to produce and to buy. In the United States, a package of instant noodles sometimes costs only ten cents.
There are many companies who manufacture Instant Noodles, some of them being:
Louis Armstrong
Louis Armstrong (August 4, 1901 – July 6, 1971) nicknamed Satchmo or Pops was an American jazz trumpeter and singer from New Orleans, Louisiana. He sang the blues and played the trumpet and the cornet. He was famous in many countries. He was also known for his good singing voice and he also encouraged the style of scat to the jazz world. Armstrong won many awards during his career.
He died of a heart attack in July 6, 1971 in Corona, Queens, New York City.
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Element
Element can mean:
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