воскресенье, 10 апреля 2022 г.
среда, 23 марта 2022 г.
What Chemistry Is and What Chemists Do
Chemistry is the study of matter and energy and the interactions between them. This is also the definition for physics, by the way. Chemistry and physics are specializations of physical science. Chemistry tends to focus on the properties of substances and the interactions between different types of matter, particularly reactions that involve electrons. Physics tends to focus more on the nuclear part of the atom, as well as the subatomic realm. Really, they are two sides of the same coin.
The formal definition of chemistry is probably what you want to use if you're asked this question on a test. You may also need to practice basic chemistry concepts with a quiz.
Why Study Chemistry?
Because understanding chemistry helps you to understand the world around you. Cooking is chemistry. Everything you can touch or taste or smell is a chemical. When you study chemistry, you come to understand a bit about how things work. Chemistry isn't secret knowledge, useless to anyone but a scientist. It's the explanation for everyday things, like why laundry detergent works better in hot water or how baking soda works or why not all pain relievers work equally well on a headache. If you know some chemistry, you can make educated choices about everyday products that you use.
What Fields of Study Use Chemistry?
You could use chemistry in most fields, but it's commonly seen in the sciences and in medicine. Chemists, physicists, biologists, and engineers study chemistry. Doctors, nurses, dentists, pharmacists, physical therapists, and veterinarians all take chemistry courses. Science teachers study chemistry. Fire fighters and people who make fireworks learn about chemistry. So do truck drivers, plumbers, artists, hairdressers, chefs... the list is extensive.
What Do Chemists Do?
Whatever they want. Some chemists work in a lab, in a research environment, asking questions and testing hypotheses with experiments. Other chemists may work on a computer developing theories or models or predicting reactions. Some chemists do field work. Others contribute advice on chemistry for projects. Some chemists write. Some chemists teach. The career options are extensive.
What Is the Importance of Chemistry?
What Is the Importance of Chemistry?
What is the importance of chemistry and why would you want to learn about it? Chemistry is the study of matter and its interactions with other matter and energy. Here's a look at the importance of chemistry and why you should study it.
Chemistry has a reputation for being a complicated and boring science, but for the most part, that reputation is undeserved. Fireworks and explosions are based on chemistry, so it's definitely not a boring science. If you take classes in chemistry, you'll apply math and logic, which can make studying chemistry a challenge if you are weak in those areas. However, anyone can understand the basics of how things work, and that's the study of chemistry. In a nutshell, the importance of chemistry is that it explains the world around you.
Chemistry Explained
- Cooking: Chemistry explains how food changes as you cook it, how it rots, how to preserve food, how your body uses the food you eat, and how ingredients interact to make food.
- Cleaning: Part of the importance of chemistry is it explains how cleaning works. You use chemistry to help decide what cleaner is best for dishes, laundry, yourself, and your home. You use chemistry when you use bleaches and disinfectants, even ordinary soap and water. How do they work? That's chemistry.
- Medicine: You need to understand basic chemistry so you can understand how vitamins, supplements, and drugs can help or harm you. Part of the importance of chemistry lies in developing and testing new medical treatments and medicines.
- Environmental Issues: Chemistry is at the heart of environmental issues. What makes one chemical a nutrient and another chemical a pollutant? How can you clean up the environment? What processes can produce the things you need without harming the environment?
We humans are all chemists. We use chemicals every day and perform chemical reactions without thinking much about them. Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything.
Importance of Taking Chemistry
Everyone can and should understand basic chemistry, but it may be important for you to take a course in chemistry or even make a career out of it. It's important to understand chemistry if you are studying any of the sciences because all of the sciences involve matter and the interactions between types of matter.
Students wanting to become doctors, nurses, physicists, nutritionists, geologists, pharmacists, and (of course) chemists all study chemistry. You might want to make a career out of chemistry because chemistry-related jobs are plentiful and high-paying. The importance of chemistry won't be diminished over time, so it will remain a promising career path.
пятница, 4 февраля 2022 г.
Power Words
atom: The basic unit of a chemical
element. Atoms are made up of a dense nucleus that contains positively charged
protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively
charged electrons.
bond: (in chemistry) A
semi-permanent attachment between atoms — or groups of atoms — in a molecule.
It’s formed by an attractive force between the participating atoms. Once
bonded, the atoms will work as a unit. To separate the component atoms, energy
must be supplied to the molecule as heat or some other type of radiation.
caffeine: A natural, plant-based
stimulant, which activates the nervous system and heart. The leaves, seeds and
fruits of many plants contain caffeine. In coffee plants and tea bushes,
caffeine acts as a natural pesticide. It will kill or harm insects that attempt
to dine on the plant. Caffeine is also toxic to some types of plants, bacteria
— even frogs and dogs.
carbohydrates: Any of a
large group of compounds occurring in foods and living tissues, including
sugars, starch and cellulose. They contain hydrogen and oxygen in the same
ratio as water (2:1) and typically can be broken down in an animal’s body to
release energy.
carbon: A chemical element that is
the physical basis of all life on Earth. Carbon exists freely as graphite and
diamond. It is an important part of coal, limestone and petroleum, and is
capable of self-bonding, chemically, to form an enormous number of chemically,
biologically and commercially important molecules. (in climate studies) The
term carbon sometimes will be used almost interchangeably with carbon dioxide
to connote the potential impacts that some action, product, policy or process
may have on long-term atmospheric warming.
catenation: A term in
chemistry for the propensity of an atom to link up — or bond — with others of
the same element to form chains. Carbon is very good at this.
chemical: A substance formed from two
or more atoms that unite (bond) in a fixed proportion and structure. For
example, water is a chemical made when two hydrogen atoms bond to one oxygen
atom. Its chemical
formula is H2O.
compound: (often used as a synonym for
chemical) A compound is a substance formed when two or more chemical elements
unite (bond) in fixed proportions. For example, water is a compound made of two
hydrogen atoms bonded to one oxygen atom. Its chemical symbol is H2O.
crude oil: Petroleum in the form as it
comes out of the ground.
crystal: (adj. crystalline) A solid
consisting of a symmetrical, ordered, three-dimensional arrangement of atoms or
molecules. It’s the organized structure taken by most minerals. Apatite, for
example, forms six-sided crystals. The mineral crystals that make up rock are
usually too small to be seen with the unaided eye.
diamond: One of the hardest known
substances and rarest gems on Earth. Diamonds form deep within the planet when
carbon is compressed under incredibly strong pressure.
dissolve: To turn a solid into a
liquid and disperse it into that starting liquid. (For instance, sugar or salt
crystals, which are solids, will dissolve into water. Now the crystals are
gone and the solution is a fully dispersed mix of the liquid form of the sugar
or salt in water.)
double bond: A type of
bond between two atoms within a molecule. In a single bond, atoms share two
electrons. In a double bond, they share four. This bond is slightly less stable
than a single bond.
electron: A negatively charged
particle, usually found orbiting the outer regions of an atom; also, the
carrier of electricity within solids.
element: A building block of some
larger structure. (in chemistry) Each of more than one hundred substances for
which the smallest unit of each is a single atom. Examples include hydrogen,
oxygen, carbon, lithium and uranium.
fertilizer: Nitrogen,
phosphorus and other plant nutrients added to soil, water or foliage to boost
crop growth or to replenish nutrients that were lost earlier as they were used
by plant roots or leaves.
field: An area of study, as
in: Her field of research is
biology.
fossil fuel: Any fuel —
such as coal, petroleum (crude oil) or natural gas — that has developed within
the Earth over millions of years from the decayed remains of bacteria, plants
or animals.
fullerenes: Molecules
of carbon that resemble tiny, soccer ball-like cages or tubes when the chemical
bonds between all of the carbon atoms are drawn. Most fullerenes are
ball-shaped. Chemists created the first of these in 1985 and nicknamed them
“buckyballs” after Buckminster Fuller, the famous architect and engineer who
designed dome-shaped structures whose shapes resemble fullerene balls. In 2020,
chemists created related all-carbon tubes, now known as fullertubes.
graphene: A superthin, superstrong
material made from a single-atom-thick layer of carbon atoms that are linked
together.
graphite: Like diamond, graphite (the
substance found in pencil lead) is a form of pure carbon. Unlike diamond,
graphite is very soft. The main difference between these two forms of carbon is
the number and type of chemical bonds between carbon atoms in each substance.
hue: A color or shade of some
color.
hydrocarbon: Any of a
range of large molecules containing chemically bound carbon and hydrogen atoms.
Crude oil, for example, is a naturally occurring mix of many hydrocarbons.
Carbon: Molecule-maker supreme
Carbon: Molecule-maker supreme
Three things make carbon special.
Covalent bonds are
those within a molecule where various atoms share an electron. Those
tight linkages hold the atoms close to one another. Each carbon atom can form
four covalent bonds at once. That’s a lot. And it’s not just that
carbon can form four bonds, but rather that it wants to form four bonds.
Carbon’s covalent bonds come in three types: single, double and triple bonds. A double bond is extra-strong and counts
as two of carbon’s four desired bonds. A triple bond is stronger still, and
counts as three. All these bonds and bond types allow carbon to make many types
of molecules. In fact, simply replacing any single bond with a double or triple
bond will give you a different molecule.
Carbon atoms tend to link up with other carbon atoms to form chains, sheets and other shapes. Scientists call this
ability catenation (Kaa-tuh-NAY-shun). Plastic is the name for a family of
organic polymers. Their long carbon chains can either be straight or branch out
like trees. Each trunk or branch of these polymers is made from a backbone of
catenated carbons. Carbon can link into ring shapes, too. Caffeine, a molecule
in coffee, is a compact, two-ring, spider-shaped molecule held together by the
catenation of carbon atoms. Carbon atoms even connect to form perfectly
spherical 60-carbon balls. These are known as buckyballs.
Hydrocarbons: The basis of fossil fuels
Crude
oil and natural gas are fossil fuels made
from a complex mix of natural organic chemicals, generally known as
hydrocarbons. That term is a mash-up of hydrogen and carbon. These molecules
are, too.
The
simplest hydrocarbon is methane (METH-ain). It’s made from a single carbon atom
bonded (covalently)
to four hydrogen atoms. A two-carbon version, ethane (ETH-ain), holds onto six
hydrogen atoms. Add a third carbon — and two more hydrogens — and you get
propane. Notice that the end of each name stays the same. Only the first part,
or prefix, changes. Here, that prefix tells us how many carbons the molecule
holds. (Peek at the back of a bottle of hair conditioner. Try to spot some of
these prefixes hidden in the long chemical names.)
Once
we reach four bound carbons, new hydrocarbon shapes become possible. Since
carbon chains can branch, four carbon atoms (and their hydrogens) may bend and
connect into unusual shapes. That results in new molecules.
In chemistry, what does it mean to be organic?
In chemistry, what does it
mean to be organic?
At a minimum, these molecules need carbon. But that’s only the first
requirement
t of 118 elements, only one
has its own field of study: carbon. Chemists refer to most molecules that
contain one or more carbon atoms as organic. The study of these molecules is
organic chemistry.
Carbon-based molecules get special attention because no other element comes
close to carbon’s versatility. More types of carbon-based molecules exist than
all non-carbon ones put together.
Scientists generally define a molecule as organic when it contains not only
carbon, but also at least one other element. Typically, that element is
hydrogen, oxygen, nitrogen or sulfur. Some definitions say that a molecule
must contain both carbon and hydrogen to be organic.
(By the way, in farming, “organic” refers to crops grown without certain
pesticides and fertilizers. That use of “organic” is very different from the
chemical definitions here.)
Living
things are built with organic molecules and operate using organic molecules.
Indeed, organic molecules perform the tasks that makes a living thing
“alive.”
DNA,
the molecular blueprint for our bodies, is organic. The energy we get from food
comes from breaking down carbon-based — organic — molecules. In fact, until the
1800s, chemists thought that only plants,
animals and other organisms could make organic molecules. Now we know better.
Our oceans created organic molecules before life even existed. Organic
molecules can also be made in the lab. Most medicines are organic. So are
plastics and most perfumes. Still, organic molecules are seen as a defining feature
of life-forms.
But living things also contain lots of molecules that are not organic.
Water is a good example. It makes up about six-tenths of our bodyweight but is
not organic. We must drink water to live. But drinking water doesn’t satisfy
hunger. A hamburger or beans, for instance, contains those organic molecules
needed to fuel our bodies’ growth.
In living things, organic molecules usually fall into one of four
categories: lipids (such as fats and oils), proteins, nucleic
acids (such as DNA and RNA) and carbohydrates (such
as sugars and starches). These molecules can get big, though still too small to
see with just our eyes. Some may even be organic molecules bonded to other
organic molecules. The big ones, made by linking a lot of littler ones, are
known as polymers.