What are chemical elements?

                                                       What are chemical elements?

                                                   Branches of chemistry

What are the branches of chemistry 

 There are 5 major branches of chemistry - organic, inorganic, analytical, physical, and biochemistry. These are further divided into many sub-branches.

• Organic Chemistry 

Organic chemistry is the study of the chemistry of life and reactions occurring in living organisms. It encompasses the study of organic reactions and the structure and properties of chemical compounds that are made up primarily of carbon and hydrogen. Sub-branches of organic chemistry include Medical Chemistry, Physical Organic Chemistry, Organometallic Chemistry, Stereochemistry, and Polymer Chemistry. 

• Inorganic Chemistry

Inorganic chemistry involves the study of the properties and behavior of inorganic compounds including metals, minerals, ceramics, crystal structures, catalysts, and most elements in the Periodic Table. It covers all chemical compounds that are ‘non-organic’ in nature. Sub-branches of inorganic chemistry include Nuclear Chemistry, Geochemistry, Bioinorganic Chemistry, Solid-State Chemistry, and Organometallic Chemistry. 

• Biochemistry

Biochemistry is the study of chemical reactions that occur in living organisms. It focuses on key molecules such as lipids, proteins, carbohydrates, neurotransmitters, and nucleic acids, and tries to explain them in chemical terms. Sub branches of biochemistry include genetics, molecular biology, clinical biochemistry, pharmacology, toxicology, and agricultural biochemistry. 

• Analytical Chemistry

Analytical chemistry involves the qualitative and quantitative analysis of the chemistry of substances. It encompasses a wide range of techniques including distillation, extraction, spectroscopy and spectrometry, separation, electrophoresis, and chromatography. Sub branches of analytical chemistry include Environmental Chemistry, Forensic Chemistry, and Bioanalytical Chemistry. 

• Physical Chemistry

Physical Chemistry applies physics to the study of chemistry. For example, it includes the applications of quantum mechanics and thermodynamics to chemistry. This branch of chemistry encompasses the study of the effect of chemical structure on the physical properties of a substance, the rate of chemical reactions, the calculation of properties and structures, and the interaction of molecules with radiation. Sub branches of physical chemistry include Quantum Chemistry, Photochemistry, Spectroscopy, Chemical Kinetics, and Surface Chemistry. 

Why Is the Sea Salty?

 

Why Is the Sea Salty?

Have you ever wondered why the ocean is salty? Have you wondered why lakes might not be salty? Here's a look at what makes the ocean salty and why other bodies of water have a different chemical composition.

The oceans of the world have a fairly stable salinity of about 35 parts per thousand. The main salts include dissolved sodium chloride, magnesium sulfate, potassium nitrate, and sodium bicarbonate. In water, these are sodium, magnesium, and potassium cations, and chloride, sulfate, nitrate, and carbonate anions.

The reason the sea is salty is because it is very old. Gases from volcanoes dissolved in the water, making it acidic. The acids dissolved minerals from lava, producing ions. More recently, ions from eroded rocks entered the ocean as rivers drained into the sea.

While some lakes are very salty (high salinity), some do not taste salty because they contain low amounts of sodium and chloride (table salt) ions. Others are more dilute simply because the water drains toward the sea and is replaced by fresh rainwater or other precipitation.

Oceans have been around a very long time, so some of the salts were added to the water at a time when gases and lava were spewing from increased volcanic activity. The carbon dioxide dissolved in water from the atmosphere forms weak carbonic acid which dissolves minerals. When these minerals dissolve, they form ions, which make the water salty. While water evaporates from the ocean, the salt gets left behind. Also, rivers drain into the oceans, bringing in additional ions from rock that was eroded by rainwater and streams.

The saltiness of the ocean, or its salinity, is fairly stable at about 35 parts per thousand. To give you a sense of how much salt that is, it is estimated that if you took all the salt out of the ocean and spread it over the land, the salt would form a layer more than 500 feet (166 m) deep. You might think the ocean would become increasingly salty over time, but part of the reason it does not is because many of the ions in the ocean are taken in by the organisms that live in the ocean. Another factor may be the formation of new minerals.

What Is an Experiment?

 

What Is an Experiment? The Short Answer

In its simplest form, an experiment is simply the test of a hypothesis. A hypothesis, in turn, is a proposed relationship or explanation of phenomena.

Experiment Basics

The experiment is the foundation of the scientific method, which is a systematic means of exploring the world around you. Although some experiments take place in laboratories, you could perform an experiment anywhere, at any time.

Take a look at the steps of the scientific method:

1. Make observations.
2. Formulate a hypothesis.
3. Design and conduct an experiment to test the hypothesis.
4. Evaluate the results of the experiment.
5. Accept or reject the hypothesis.
6. If necessary, make and test a new hypothesis.

Types of Experiments

• Natural Experiments: A natural experiment also is called a quasi-experiment. A natural experiment involves making a prediction or forming a hypothesis and then gathering data by observing a system. The variables are not controlled in a natural experiment.
• Controlled Experiments: Lab experiments are controlled experiments, although you can perform a controlled experiment outside of a lab setting! In a controlled experiment, you compare an experimental group with a control group. Ideally, these two groups are identical except for one variable, the independent variable.
• Field Experiments: A field experiment may be either a natural experiment or a controlled experiment. It takes place in a real-world setting, rather than under lab conditions. For example, an experiment involving an animal in its natural habitat would be a field experiment.

Variables in an Experiment

Simply put, a variable is anything you can change or control in an experiment. Common examples of variables include temperature, duration of the experiment, composition of a material, amount of light, etc. There are three kinds of variables in an experiment: controlled variables, independent variables and dependent variables.

Controlled variables, sometimes called constant variables are variables that are kept constant or unchanging. For example, if you are doing an experiment measuring the fizz released from different types of soda, you might control the size of the container so that all brands of soda would be in 12-oz cans. If you are performing an experiment on the effect of spraying plants with different chemicals, you would try to maintain the same pressure and maybe the same volume when spraying your plants.

The independent variable is the one factor that you are changing. It is one factor because usually in an experiment you try to change one thing at a time. This makes measurements and interpretation of the data much easier. If you are trying to determine whether heating water allows you to dissolve more sugar in the water then your independent variable is the temperature of the water. This is the variable you are purposely controlling.

The dependent variable is the variable you observe, to see whether it is affected by your independent variable. In the example where you are heating water to see if this affects the amount of sugar you can dissolve, the mass or volume of sugar (whichever you choose to measure) would be your dependent variable.

Chemistry

Chemistry

 

Sitting between biology and physics, the field of chemistry is sometimes called the central science. This branch of science deals not with the most basic elements of reality, such as fundamental particles, or the complex world of living organisms, but the in-between world of atoms, molecules and chemical processes.

Chemistry is the study of matter, analysing its structure, properties and behaviour to see what happens when they change in chemical reactions. As such, it can be considered a branch of physical science, alongside astronomy, physics and earth sciences including geology.

An important area of chemistry is the understanding of atoms and what determines how they react. It turns out reactivity is often largely mediated by the electrons that orbit atoms and the way these are exchanged and shared to create chemical bonds.

Chemistry has now split into many branches. For instance, analytical chemists might measure the traces of compounds in ancient pottery to discern what people were eating thousands of years ago.

Biochemistry is the study of the chemical processes that take place in living organisms, for instance in farming, and on the effect the resulting produce will have on our body’s metabolism.

Organic chemistry, the study of compounds which contain carbon, connects up molecules in new ways to build and analyse an array of materials, from drugs to plastics to flexible electronics. Inorganic chemistry is the study of materials based primarily on elements other than carbon. Inorganic compounds can be pigments, fertilisers, catalysts and more.

Physical chemistry involves looking at chemistry through the lens of physics to study changes in pressure, temperatures and rates of conversion, for example, as substances react.

Chemists help us understand the nature and properties of the world around us and the history of chemistry is replete with discoveries that have furthered this. Antoine Lavoisier paved the way for modern chemistry. He helped give the field structure by developing an ordered language and symbolism. And his understanding of the constituent parts of air, as well as the process of combustion, disproved centuries of incorrect thinking. But there is perhaps no more important chemist than  Dmitri Mendeleev, the Russian who in 1869 wrote down the symbols for all the known chemical elements, arranging them according to their atomic weight. He had created the periodic table, making it possible to predict how any given element would react with another, the compounds it would form and what kind of physical properties it would have.

States of matter

 States of matter

How many states of matter are there?

There are four states of matter commonly found in the universe and on Earth. However, there are many more states of matter that are either man-made or very rarely found either on Earth or in the universe.

Are there 5 states of matter?

Yes, there are five (and more) states of matter. However, only four are commonly found on Earth and in the universe. The most common states of matter are solid, liquid, gas, and plasma. Many other states of matter exist (like degenerate matter, amorphous solids, and supercritical fluids), but they are rarely found in nature.

What are the three states of matter, and what are some examples of each state?

The three main states of matter commonly found naturally on Earth are:

solid - bricks, ice, wood, paper

liquid - milk, water, honey

gas - helium, hydrogen, oxygen, air

The best way to start a discussion on the states of matter is to answer the question, 'What is matter?' Matter is the material that makes up all things in the universe. In its smallest form it is unseeable, but as it combines it grows into atoms that become molecules that become everything in existence.

There are 4 states of matter, meaning matter can exist (or present) in four different ways in the universe. Matter can exist in the following forms:

Solid

Liquid

Gas

Plasma

Solids, liquids, and gases are found in abundance in nature on Earth. The characteristics of solids, liquids, and gases change over three common variables: volume, shape, and energy level of the matter.

Solid State of Matter & Solid Matter Examples

Matter has the least amount of inert energy when in a solid state of matter form. This is because when in solid form, the atoms that make up the object are very tightly packed together and exhibit very little, if any, movement (a molecular microscope can sometimes pick up very slight movement in the atomic level of a solid that is not apparent to the human eye). This tightly packed formation of the solid state of matter equates to high density for solids.

Solids have a definite shape and volume. Solid matter does not have mobile molecules, thus it must stay one shape and size until acted upon by an outside force. Due to this forced stillness in the molecules, a solid will always have a definite (measurable) volume and will maintain its own shape.

Imagine if bricks could change shape and volume at random. That would be disastrous. Which of the practice examples above has a constant shape and volume? Gold. Gold is an example of a metallic solid.

Liquid State of Matter & Liquid Matter Examples

While solids have little to no energy (movement), liquid states of matter have moderate energy, and atoms/molecules within a liquid do move. The word 'fluid' elicits the idea of movement and liquids are certainly fluid. Molecules in liquids are loosely packed together meaning they have moderate density.

In terms of volume, liquids do have a definitive volume, meaning it is possible to measure the volume of a liquid. However, they do not have a definite shape. Liquids take on the shape of whatever vessel they are in.