Science & Technology

Sub Category

rinki
1 Views · 12 days ago

new bhavishyvani (year2023)new video wirh mvm studio

Mahesh
6 Views · 13 days ago

⁣Mysterious dialer number is fake or real .

Todd1lowery
4 Views · 29 days ago

planet on Earth

PelisMax
2 Views · 2 months ago

joseiakdkia

leonardidatz
45 Views · 6 months ago

med Infos

Mahyun
29 Views · 8 months ago

⁣Blackview BV9100 Indonesia ( 720 X 1280 )

syril
4 Views · 10 months ago

andree

syril
6 Views · 10 months ago

andree

Madi Morton
7 Views · 10 months ago

Do not try this at home. Ask your parents first before you let ants in your room.

vdube
76 Views · 1 year ago

⁣Learn how to harden vegetable oils through a chemical process demonstrated on the example of Margarine.

vdube
64 Views · 1 year ago

⁣Photosynthesis and respiration help carbon to be cycled in nature by using energy from the sun.

As living things grow, they have to build up large polymer molecules from small molecules. Protein comes from joining amino acids together, cellulose and starch from joining sugars, and DNA from the bases, sugar and phosphate.

Plants can make these simple molecules from the carbon they capture from photosynthesis with added elements from the minerals that they get from the soil.

Animals have to get their molecules ‘ready made’ when they eat plants or other animals - but first they have to break the food polymers back into the small molecules through digestion. This all needs lots of energy.

Living things get their energy from respiration. Some of the monomers (often carbohydrates in humans) have to be re-joined with oxygen.

The carbon dioxide gets back into the food web through photosynthesis.

vdube
35 Views · 1 year ago

⁣Learn the basics about aluminium - anodising it and the uses of aluminium, when learning about metals and their reactivity as a part of environmental chemistry.

Aluminium is a very reactive metal. It's protective layer of oxide is very important.

Aluminium is used for cooking utensils, cooking foil, drink cans, window frames, or aeroplanes. It is a shiny metal that does not corrode. It is unreactive because of it's hard thin layer of oxide that forms over all exposed surfaces. This layer is so tight that water and air cannot get under it. If it gets scratched a new thin oxide layer immediately forms stopping further corrosion.

Aluminium has many useful properties, which is why it is so widely used. Some of these are it is abundant, it is a metal and so is strong, it has a low density, it conducts electricity and it does not corrode.

Shiny aluminium is made of anodised aluminium. The anodising process builds up the protective oxide layer by making the aluminium the anode in an electrolytic cell containing an acid.

The new layer is very hard, inert and can absorb dyes to colour the film, giving the bright shiny colours.

vdube
38 Views · 1 year ago

⁣Learn the basics about electroplating.

The anode is positively charged, and the cathode is negatively charged. They are immersed in a solution called an electrolyte.

The electrolyte and the anode are selected based upon the material that you are electroplating with. So if you want to create a copper plate on the cathode, you would use a copper anode and a copper based electrolyte solution.

When the battery is turned on, the positively charged ions in the electrolyte are attracted to the cathode. Here, they gain electrons which is known as reduction.

When the battery is turned on, the negatively charged ions in the electrolyte solution are attracted to the anode. The atoms within the anode, so the copper atoms in copper plating, lose electrons which is known as oxidation. These copper atoms are now positively charged and dissolve into the electrolyte solution. Once in the electrolyte solution, because they are now positively charged they are attracted over to the negative cathode. Hence electroplating the cathode.

The electrons flow from the anode to the cathode.

Half equations occur at each anode, with oxidation at the anode and reduction at the cathode.

Just remember, oxidation is loss of electrons and reduction is gain.

vdube
51 Views · 1 year ago

⁣Learn the basics about the renewable feedstocks principle of green chemistry, as a part of environmental chemistry.

Many plastic products are derived from crude oil, which is a non-renewable resource.

It takes millions of years for dead carbon-based living
organisms to be compressed by layers and layers of sediment before we get crude oil. Hence there is not an infinite supply of crude oil.

The term renewable feedstock refers to raw material derived from natural resources. The usage of renewable feedstock reduces the amount of harmful waste produced from the crude oil refinery and distillation processes.

Most printer inks are made from crude-oil derived pigments. Soy-based inks are being developed, which come from a plant and so is a renewable resource. The recycling process of paper products printed with soy-based inks is also considerably more environmentally friendly. When paper products are recycled, the ink on paper needs to be removed first which is difficult with petroleum based inks, but significantly easier to de-ink soy-based inks.

vdube
30 Views · 1 year ago

⁣Learn the basics about the green chemistry principle that concerns energy efficiency, as a part of environmental chemistry.

Many chemical processes are designed to be as efficient as possible. It is very costly if a chemical synthesis is not designed to be efficient, such as requiring heat for the reaction requires unnecessary energy.

Whenever possible a chemical synthesis is designed to use the least amount of energy possible. It is also very costly to use more energy than necessary. Light Bulbs are also now being designed so that they are more energy efficient.

In industry, chemists are aiming to modify or develop reactions so that they will proceed at standard ambient temperature and pressure.This is because it costs energy to produce both high and very low temperatures. Energy efficient catalysts also help in achieving efficient reactions.

vdube
40 Views · 1 year ago

⁣Learn the basics about the principle of green chemistry that concerns catalysis, as a part of environmental chemistry.

A catalyst increases the rate of a chemical reaction. This means that desired products can be made more quickly, using a lower energy pathway.

A catalyst is regenerated so it can be reused over and over again.

Catalysts can however be expensive.

In industry, research into the desulfurization of fuels is taking place to reduce atmospheric sulphur. Catalysts are being developed to remove sulphur from fuels to prevent atmospheric issues later, such as acid rain.

Fuel cells are also being developed, as they do not require fossil fuels to be burnt. However, electrocatalysis is also being undertaken to improve the efficiency of redox reactions that take place in these cells.

vdube
27 Views · 1 year ago

⁣Learn the basics about how atoms bond when learning about the structure of atoms.

Bonds form by the attraction of negatively charged electrons and the positive nucleus of atoms. Atoms have a positively charged tiny nucleus which contains almost all the atom’s mass, surrounded by shells of negatively charged electrons. Each shell is able to hold only up to a fixed number of electrons when it is said to be full.

Hydrogen has a single positive charge in the nucleus and a single electron. If two hydrogen atoms approach each other, there is an attraction: the positive charge and the negative electron charge attract. However the first shell, for all atoms, can only contain two electrons so once the two Hydrogen atoms come together the two electrons essentially ‘fill’ the outer shell of both Hydrogen atoms. The atoms are essentially ‘glued’ together by the attraction of the two electrons and the two nuclei.

The same form of electron share bonding occurs between any non-metallic elements, with the outer shell quickly becoming full, limiting the number of bonds that form.

When there are four electrons in the outer shell, such as with carbon and silicon there is room for four more electrons so 4 bonds form. In this case it is possible to build up a 3-D structure with the bonding going on forever. In this way we see that carbon and silicon, as elements, have atoms chemically bonded into a 3D lattice so they are both solids at room temperature and very difficult to melt and vaporise. They are giant covalent structures.

Metallic bonding is the way all metals and alloys are bonded, and explains the typical properties of metals. Atoms can be added as much as you want and there will never be enough electrons to fill the outer shell. So in metallic bonding, the atoms form a closely packed lattice where the atoms are not bonded by fixed pairs of electrons, but rather by a ‘sea’ of electrons roaming these partially filled outer shells at will.

When two different atoms approach each other, covalent bonds can form. The number of electrons that are shared depends upon how many electrons are missing from the outer shells of the atoms.

Overall, in this video you will learn how two atoms which approach each other have the possibility to bond if there is space in their outer electron shells.
Non-metallic elements will tend to form self contained small molecules giving rise to volatile solids, liquids and all gases.
Carbon and silicon will give rise to giant structures.
Metallic elements will bond together to form metallic structures with loose electrons.
When metal bonds with a non-metal ionic compounds are formed.

vdube
36 Views · 1 year ago

⁣Learn the basics about Alkaline Earth metals which are a group of chemical elements in the periodic table with very similar properties? What are those properties? Find out more in this video!

vdube
27 Views · 1 year ago

⁣Learn the basics about Alkaline Earth metals which are a group of chemical elements in the periodic table with very similar properties? What are those properties? Find out more in this video!

vdube
24 Views · 1 year ago

⁣Learn the basics about separating solutions, mixtures and emulsions when learning about separation techniques as a part of chemical tests.

A solution is a mixture of two or more substances in the same phase. It is formed when a solute dissolves in a solvent. When salt is dissolved in water, a solution is formed. A solution can also be formed when two or more miscible liquids are mixed together.

To separate dissolved salt from water, evaporate as much water as possible, leaving behind white salt crystals.This separation technique is known as evaporation.

To separate ethanol from water, use the fact that both substances have very different boiling points. This mixture can be separated by simple distillation. The lower boiling component will boil and evaporate first, so it can easily be collected separately from the ethanol.

Salt and water, and ethanol and water are homogenous mixtures – this means that the components of the mixture are in the same phase, or the composition of the mixture is uniform throughout.

Heterogeneous mixtures are where the components in the mixture are not in the same phase, or the composition of the mixture is uneven. A mixture of sulfur and iron filings is a heterogenous mixture.

There are many different techniques to separate mixtures, depending on whether the mixture is homogenous or heterogeneous.

Magnets can be used to separate out magnetic components in heterogenous mixtures. Salt and sand can be separated using water to dissolve the salt, and then evaporation to separate the salt back from the water once more.

Two immiscible liquids, such as oil and water, can be separated using a separatory funnel.




Showing 1 out of 30