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Showing posts with the label Chemistry

### What is a median in math?

What is a median in math? The median is the middle number in a sorted, ascending or descending, list of numbers and can be more descriptive of that data set than the average. Median is the middle number in a sorted list of numbers. To determine the median value in a sequence of numbers, the numbers must first be sorted, or arranged, in value order from lowest to highest or highest to lowest. If there is an odd amount of numbers, the median value is the number that is in the middle, with the same amount of numbers below and above. If there is an even amount of numbers in the list, the middle pair must be determined, added together, and divided by two to find the median value. The median is sometimes used as opposed to the mean when there are outliers in the sequence that might skew the average of the values.  You may like What is manifesting? What is electric Charge? What is Binary? What is physics? What is pH scale? What is quantum mechanics?

### Liquids which are miscible

If miscible liquids are to be separated, then this can be done by fractional distillation. The apparatus used for this process is shown in the photo and diagram in Figure, and could be used to separate a mixture of ethanol and water.  Fractional distillation relies upon the liquids having different boiling points. When ethanol and the water mixture is heated the vapours of ethanol and water boil off at different temperatures and can be condensed and collected separately.  Ethanol boils at 78 °C whereas water boils at 100 °C. When the mixture is heated the vapour produced is mainly ethanol with some steam. Because water has a higher boiling point of the two, it condenses out from the mixture with ethanol. This is what takes place in the fractionating column. The water condenses and drips back into the flask while the ethanol vapour moves up the column and into the condenser, where it condenses into liquid ethanol and is collected in the receiving flask as the distillate. When all the et

### Liquids which are immiscible

If two liquids are immiscible they can be separated using a separating funnel. The mixture is poured into the funnel and the layers allowed to separate.  The lower layer can then be run off by opening the tap as shown in Figure. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Separating liquid mixtures Simple distillation

### Separating liquid/liquid mixtures

In recent years there have been many oil tanker disasters, just like the one shown in Figure. These have resulted in millions of litres of oil being washed into the sea. Oil and water do not mix easily. They are said to be immiscible. When cleaning up disasters of this type, a range of chemicals can be added to the oil to make it more soluble. This results in oil and water mixing with each other. They are now said to be miscible. The following techniques can be used to separate mixtures of liquids. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Simple distillation

### Simple distillation

If we want to obtain the solvent from a solution, then the process of distillation can be carried out. The apparatus used in this process is shown in Figure. Water can be obtained from saltwater using this method. The solution is heated in the flask until it boils. The steam rises into the Liebig condenser, where it condenses back into the water. The salt is left behind in the flask. In hot and arid countries such as Saudi Arabia, this sort of technique is used on a much larger scale to obtain pure water for drinking. This process is carried out in a desalination plant. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures

### Changing of states of matter- Solid, Liquid and Gases

The kinetic theory model can be used to explain how a substance changes from one state to another. If a solid is heated the particles vibrate faster as they gain energy. This makes them ‘push’ their neighboring particles further away from themselves. This causes an increase in the volume of the solid, and the solid expands. The expansion has taken place. Eventually, the heat energy causes the forces of attraction to weaken. The regular pattern of the structure breaks down. The particles can now move around each other. The solid has melted. The temperature at which this takes place is called the melting point of the substance. The temperature of a pure melting solid will not rise until it has all melted. When the substance has become a liquid there are still very significant forces of attraction between the particles, which is why it is a liquid and not a gas. Solids that have high melting points have stronger forces of attraction between their particles than those which have low meltin

### Explaining the three states of matter

In a solid, the particles attract one another. There are attractive forces between the particles which hold them close together. The particles have little freedom of movement and can only vibrate about a fixed position. They are arranged in a regular manner, which explains why many solids form crystals.  It is possible to model such crystals by using spheres to represent the particles. If the spheres are built up in a regular way then the shape compares very closely with that of a part of a chrome alum crystal. Studies using X-ray crystallography have confirmed how the particles are arranged in crystal structures. When crystals of a pure substance from under a given set of conditions, the particles present are always packed in the same way. However, the particles may be packed in different ways in crystals of different substances. For example, common salt (sodium chloride) has its particles arranged to give cubic crystals as shown in Figure. In a liquid, the particles are still close t

### The kinetic theory of matter

The kinetic theory helps to explain the way in which matter behaves. The evidence is consistent with the idea that all matter is made up of tiny particles. This theory explains the physical properties of matter in terms of the movement of its constituent particles. The main points of the theory are: All matter is made up of tiny, moving particles, invisible to the naked eye. Different substances have different types of particles (atoms, molecules, or ions) that have different sizes. The particles move all the time. The higher the temperature, the faster they move on average. Heavier particles move more slowly than lighter ones at a given temperature. The kinetic theory can be used as a scientific model to explain how the arrangement of particles relates to the properties of the three states of matter. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple dis

### What is activation energy?

The least amount of energy required for active atoms or molecules to a state in which they can undergo a chemical reaction is known as activation energy.  You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple distillation

### What is catalyst poison?

The substances which destroy the catalytic activity of a catalyst are known as catalyst poisons.  You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple distillation

### What is catalyst?

The substances that make a reaction take place faster but are not used up in the reaction are called catalysts.  You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple distillation

### What is rate of reaction?

The rate of decrease of concentration of a reactant or the rate of increasing concentration of the product is known as the rate of reaction. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple distillation

### What is green chemistry?

Green chemistry is the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture, and application of chemical products. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple distillation

### What is essential oil?

The oil which is extracted from roots, leaves, flowers, and seeds is known as an essential oil. For example - Amla, Olive etc. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple distillation

### What is perfumery?

Perfumeries include different types of cosmetics and perfumed personal care products. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple distillation

### What is coagulation?

Coagulation is a process of bringing the suspended fine particles together to form a bulk material. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple distillation

### What is molt vinegar?

Conversion of barley's starch or sugar into acetic acid by the process of malting is known as malt vinegar. This vinegar is widely used in making pickles. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple distillation

### What is suspension?

Suspension is a kind of non-homogenous mixture. In a suspension, the solute particles can be observed by naked eye or microscope. If kept standing, the solute particles settle at the bottom. You may also read Types of Computer Main components of computer systems Hardware and Software Liquids which are miscible Liquids which are immiscible Separating liquid mixtures Simple distillation

### What is preservatives?

Natural or chemical substances which are used in a small amount to protect food from the contamination of micro-organisms. Preservatives increase the shelf-life and taste of food. You may like Do I need car insurance? What is car insurance? How could I get cheaper car insurance? What is auto insurance? Why Adulterant food is the barrier to sound health? What are the producers? What are food preservatives? What is food chain? What is tertiary consumer?

### What is an ion?

Compounds composed of metals and nonmetals contain charged species. The charged species are known as ions. An ion is a charged particle and can be negatively or positively charged. A negatively charged ion is called an ‘anion’ and the positively charged ion, a ‘cation’. Take, for example, sodium chloride (NaCl). Its constituent particles are positively charged sodium ions (Na + ) and negatively charged chloride ions (Cl - ). Ions may consist of a single charged atom or a group of atoms that have a net charge on them. A group of atoms carrying a charge is known as a polyatomic ion. You may like Do I need car insurance? What is car insurance? How could I get cheaper car insurance? What is auto insurance? Why Adulterant food is the barrier to sound health? What are the producers? What are food preservatives? What is food chain? What is tertiary consumer?

### Molecules of elements

The molecules of an element are constituted by the same type of atoms. Molecules of many elements, such as argon (Ar), helium (He), etc. are made up of only one atom of that element. But this is not the case with most of the nonmetals.  For example, a molecule of oxygen consists of two atoms of oxygen and hence it is known as a diatomic molecule, O2. If 3 atoms of oxygen unite into a molecule, instead of the usual 2, we get ozone. The number of atoms constituting a molecule is known as its atomicity.  Molecules of metals and some other elements, such as carbon, do not have a simple structure but consist of a very large and indefinite number of atoms bonded together. You may like Do I need car insurance? What is car insurance? How could I get cheaper car insurance? What is auto insurance? Why Adulterant food is the barrier to sound health? What are the producers? What are food preservatives? What is food chain? What is tertiary consumer?