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Analytical Balance

Analytical Balance

What is an analytical balance?

what is Analytical Balance
Analytical balance is a lab-instrument used to determine mass of any matter very precisely. These analytical balances are very sensitive and expensive lab-instruments, and also upon the accuracy and precision of analytical balance the accuracy of lab-analysis result depends so handle these balances very carefully. Generally used analytical balances are balances with the capacity of 100 gram to 200 gram and the sensitivity of 0.1 milligram to 0.001 milligram. For any quantitative chemical analysis there is need of analytical balance for the weighing of sample for analysis and weighing of reagents for solution preparation. Analytical balance pan used to put sample on it is enclosed in a glass-fitted case, means analytical balance sensitivity requires that it to be protected by the draft shield or enclosure.
analytical balances

Definition of Analytical Balance

Analytical balance is a lab instrument with a scale to measure the mass to a high degree of precision. Generally used analytical balances are balances with the capacity of 100 gram to 200 gram and the sensitivity of 0.1 milligram to 0.001 milligram.

Where are analytical balances used?

Analytical balances are used in labs so also known as ‘Lab Balances’. In labs analytical balances are used for quantitative analysis like for measuring of sample, preparation of standard solutions etc.

How to weigh on an analytical balance?

These are the following steps to start weighing operation on an analytical balance-
  • Wear hand gloves.
  • Open the door of balance and place the container on pan of analytical balance.
  • Now, close the door of the analytical balance and wait for some time.
  • After some time value on balance display or scale get stabilizes, and shows some weight.
  • Now, press the tare button to get 0.0000 gram reading on display.
  • Add the sample until the required weight.
  • Now, close the door and wait for some time.
  • After some time value on balance display or scale get stabilizes, and shows some weight.
  • Record the net weight.
  • Clean the balance after use.

What is analytical balance uncertainty?

Analytical balance uncertainty is the margin of error in weighing, means when making measurements or weighing there is always an element of uncertainty in measurements or weighing. Determination of measurement uncertainty in analytical balance results is an integral part of the balance calibration.

Why should I calibrate my analytical balance?

Calibration of analytical balance is very necessary because balance calibration ensures that weighing balance is precise, correct, truthful, accurate, and satisfies different standards like ISO, GLP, and GMP. Calibration of analytical balances should be documented, as it specifies the quality of measurements. Documented calibration should be performed repeatedly, at some time intervals (like 3months+/-15days). 

How should I calibrate my analytical balance?

You should not calibrate your balance on your own, but it should be calibrated by third party. Means, calibration of balance is performed by third party authorized service technician.  This third party authorized service technician follow a standard procedure, and utilizes some calibration software to calibrate your analytical balance.

What is the analytical balance minimum weight?

Generally minimum weight of analytical balance is not fixed, means it is different for different balances and it depends on different factors like performance of load cell, location of balance, and surrounding environment. Minimum weight is smallest weight that can be measured with accuracy. If we try to measure below this minimum weight, we get results higher relative measurement uncertainty than the required weighing accuracy. So measurements below minimum weight cannot be trusted.
If you want to determine the minimum weight of your balance, you need to assess measurement uncertainty in the working environment.

Analytical balance accuracy and precision – what is the difference and how to test them?

Precision in balances refers to the closeness of two or more measurements to each other, means if we measure 5gram sample and its display shows 5.0001 in 1st time measurement, 5.0000 in 2nd time measurement, 4.9999 in 3rd measurement, and 5.0000 in 4th measurements so all these results (5.0001, 5.0000, 4.9999, and 5.0000) are very close to each other.
Accuracy in balances means how accurate result it gives so, Accuracy in balances refers to the closeness of a measured value to a known value, and Accuracy in balances is based on repeatability, readability, eccentricity and non-linearity. Accuracy of analytical balance can be tested using
  • A traceable calibrated weight also known as external reference weight having a known mass. And these weights are calibrated by third party and come with documented proof.
  • Accuracy of balance must be determined at its location of use.


Do you know ?

What is Analytical Chemistry ?

Analytical chemistry is all about, what an analytical chemist do in an analytical chemistry lab. And simply we can say that analytical chemistry is the branch of chemistry for qualitative analysis and quantitative analysis of compounds and mixtures by using different test methods and techniques like flame tests, chemical tests, precipitation, titration, chromatography, spectroscopy, separation, microscopy etc.
Definition of Analytical Chemistry- Analytical Chemistry is the branch of chemistry deals with the study of material examination to separate out them into different components and identifying all components and how much these components present in material. There are different analytical methods and techniques to perform these tasks... read more

Chemical Reaction Quiz Part16

  Chemical Reaction Quiz

Science Quiz by www.ChemistryNotesInfo.com
Source www.reddit.com
This Chemical Reaction Quiz part16 is based on chemical reactions.

1. Chemical reaction always gives-

Reactants
A change of state
A different substance
Water
All of the above


2. From given below, 4-balanced chemical equations, which is example of combustion reaction-

2Mg + O2 → 2MgO
2N2 + 3H2 → 2NH3
CaO + H2O → Ca(OH)2
2Na + Cl2 → 2NaCl
2CH4 + 4O2 → 2CO2 + 4H2O


3. To balance a chemical equation, you should need to change-

Chemical Formulas
Direction of the arrow
Coefficients
Subscripts
Superscripts


4. In chemistry, if you try to balance a chemical equation by changing its subscripts, than you change the-

Atomic number
Atomic Mass
Mass of the reactants
Number of molecules of product
Identity of the compound


5. From given below, 4-balanced chemical equations, which is example of double displacement reaction-

NH4Cl → NH3 + HCl
Cd(NO3)2 + Na2S → CdS + 2NaNO3
2Mg + O2 → 2MgO
2H2O2 → 2H2O + O2
2N2 + 3H2 → 2NH3


6. Chemical Reaction, KClO3 → KCl + O2 is a-

Synthesis Reaction
Decomposition Reaction
Combustion Reaction
Single Displacement Reaction
Double Displacement Reaction


7. Which scientist first determined that the masses of the reactants and the products in a chemical reaction must be same-

Lavoisier
Galileo
Newton
Archimedes
Pasteur


8. Combination reactions (also known as Synthesis Reaction) always-

Involve an element and an ionic compound
Require oxygen gas
Use only one reactant
Form only one product
form only two product


9. In a chemical reaction, the arrow means-

A reaction is happening
The equation is balanced
The products flow into reactants
The two sides are equal
All of the above


10. In a decomposition reaction-

Energy in the form of light or heat is often released
Reactants are commonly two ionic compounds in the aqueous solution
one of the reactant is generally water
Form only one product
Reactants in the chemical reaction are usually a metal and a nonmetal


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Amino Acids

Amino Acids

Definition of Amino Acid

Amino acid is a simple organic compound that contains a carboxyl (—COOH) and an amino (—NH2) group.

What are Amino Acids?

Amino acids are organic compounds containing carboxyl (—COOH) and amino (—NH2) functional group with side chain, this side chain is specific to amino acid. Carbon, Hydrogen, Oxygen and Nitrogen are some important element which present in amino acids. Some other elements may also present in side chain of some amino acids.

Importance of Amino Acids

As we all know that our body contains large amount of proteins also these proteins play important role in biological processes happening within human body. Amino acids are building blocks of these proteins means proteins contain amino acids.
Amino acids play key role in many body functions like cell structure, storage and transport of nutrients, proper functioning of organs, proper functioning of glands, proper functioning of arteries, proper functioning of tendons, healing of wounds, repairing tissues, removal of metabolic waste etc.

Amino Acids

There are so many amino acids present in nature but gene codes only 20 amino acid. Essential amino acids are type of amino acid which can not produced by human body so they are needed in dietary food. Two amino acids combines by a peptide bond to form dipeptide.
peptide bond
And amino acids further added to grow chain of peptides to form poly-peptide or protein.

Areas of use of Amino Acids

1. Anti-aging

Supply of amino acids to the body provides repair treatment means nourish human skin, nails and hair result in delay aging process naturally. Supply of amino acids strengthens connective tissue to keep our skin smooth, shine, glowing and elastic. Creatine play very important role to keep skin healthy and this creatine is made up of amino acids like Arginine and Methionine. Glutamine amino acid is responsible to regulate acid-base balance as a result it supports healthy skin. Carnitine is a di-peptide containing two essential amino acids lysine and Methionine. Carnitine helps in burning fat to produce energy so also known as fat burner so also added in fitness and wellness program.

2. Arthritis

Amino acid Methionine helps in cartilage formation, also Methionine is essential amino acid so do not get produced within human body but need to be provided from outside i.e. from diet or food. Methionine also donates sulphur which helps in joint cartilage creation. Along with amino acids vitamins and minerals are also required for healthy joints.

3. Cholesterol

Arginine amino acid helps in lowering the cholesterol level.

4. Diabetes

In diabetes person’s blood sugar level get high than normal level due to many reasons like pancreas do not produce enough insulin, insulin resistance etc. Amino acid Arginine help in reducing insulin resistance by increasing sensitivity of our body cells toward insulin so insulin get easily absorbed.

5. Fat Burning

Goal of weight loss is achieved by fat burning. Human growth hormone is an important fat burning hormone and amino acids Arginine, Glutamine and Methionine helps to secrete this hormone.

6. Hair and Nails

Amino acid Methionine prevents hair loss and strengthens nails. Amino acid Glutamine and Arginine increases hair growth.

Zwitterions

zwitterion
•    Below pH 2.2 amino acid have net charge of +1 due to the predominant form of amino acid have a neutral carboxylic acid functional group and a positive α-ammonium.
•    Above pH 9.4 amino acid have net charge of -1 due to the predominant form of amino acid have a negative carboxylate and neutral α-amino group.
•    At pH between 2.2 and 9.4 amino acid have net charge of ZERO due to the predominant form of amino acid have both a negative carboxylate and a positive α-ammonium functional group and this molecular state of amino acid is known as a Zwitterion.

Isoelectric Point

 Isoelectric point is a pH at which molecule carry zero net electric charge. In case of amino acids at pH between 2.2 and 9.4 amino acid have net electric charge of ZERO so this range of pH gives Isoelectric Point of Amino Acids as shown in below image.

List of Amino Acids

list of amino acids

Essential Amino Acids

Essential amino acids are amino acids which cannot be synthesized by the human body so these amino acids must be supplied in diet. The nine essential amino acids, which human body cannot synthesize are phenylalanine, Valine, Threonine, Tryptophan, Methionine, Leucine, Isoleucine, Lysine, and Histidine i.e. in one letter for amino acids are as follows- F, V, T, W, M, L, I, K, H.
Six additional amino acids are measured conditionally essential in the human diet. These six amino acids are Arginine, Cysteine, Glycine, Glutamine, Proline, and Tyrosine i.e. in one letter for amino acids are as follows- R, C, G, Q, P, Y.
Five amino acids are not essential in humans because they fully synthesized in the body. These five amino acids are Alanine, Aspartic Acid, Asparagine, Glutamic Acid, and Serine i.e. in one letter for amino acids are as follows- A, D, N, E, S.

List of Essential Amino Acids and Non-Essential Amino Acids

List of Essential Amino Acids and list of Non-Essential Amino Acids

Amino Acid Images





















Density

DENSITY

Density of many samples is measured in labs for example in unites states oil and gas industry, they define density in general way as 'weight per unit volume' although 'weight per unit volume' is not density it is 'Specific Weight' so density is 'mass per unit volume'. Density is also known as "Volumetric Mass Density". Generally different materials have different density. Chemical element Osmium (Os having atomic number 76) is naturally occurring densest element. To simplify the comparison of densities of different materials or liquids it is needed to replace density with "relative density" as relative density is dimensionless quantity. Relative Density is also called "Specific Gravity". Specific gravity or relative density is the ratio of density of sample material to the density of standard material. Generally water is taken as standard material. If we take water as standard material than if we get relative density of a material is less than '1' means that material floats in water. Water has highest density at 4 °C i.e. 1000Kg/m3.
Density of material depends on the temperature and pressure. Effect of temperature and pressure is very less on solid and liquid but effect of temperature and pressure is very high on gases. If we increase pressure on given material than its volume get decrease that result in increase in density, similarly If we decrease pressure on given material than its volume get increase that result in decrease in density. And in case of temperature, if we increase temperature on given material than its volume get increase that result in decrease in density, similarly if we decrease temperature on given material than its volume get decrease that result in increase in density. But their are some exceptions which do not follow these rules, one of them is water means when temperature of water decreases than it makes solid ice which float on liquid water as ice have less density than liquid water i.e. Density of ice is 916.7 Kg/m3 at 0 °C, and water has a density of 999.8 Kg/m³ at 0 °C.

Definition of Density

                           Density of a material is defined as its mass per unit volume.

Symbol of Density

                             Symbol of density is 'ρ' or 'D' and pronounces as 'rho'.

Formula of Density

                             Density = Mass/Volume
or,
           ρ = m/V
where,
           ρ is density, m is mass and V is volume.
  • When numerator (mass) is much larger than denominator (volume) in density formula, that shows the given substance has higher density, but when denominator (volume) is much larger than the numerator (mass), that shows the given substance has lower density.

SI Unit of Density

                             SI Unit of Density is Kg/m3 or g/cm3

Instruments used to measure Density

Hydrometer and Thermometer is used to measure the density of liquids.
Hydrometer to measure Density
Hydrometer


Hydrometer dip in mineral oil and engine oil to measure the Density of these samples
Hydrometer dip in mineral oil and engine oil to measure the Density of these samples


Density Chart

Material
Density (Kg/m3)
Remark
Air
1.2
At sea level
Milk
1027 to 1033
At 20 oC
Honey
1420
At 20 oC
Coconut Oil
925
At 15 oC
Cotton Seed Oil
926
At 16 oC
Olive Oil
918
At 15 oC
Sunflower Oil
919
At 20 oC
Rice Bran Oil
918
At 20 oC
Groundnut Oil
913
At 20 oC
Liquid Hydrogen
70
At about -255 oC
Ice
916.7
At 0 oC
Fresh Water
1000
At 4 oC
Plastics
1175
Approx for PVC
Glycerol
1261
Also called Glycerine or Glycerin
Aluminium
2700
Chief ore of Aluminium is Bauxite
Diamond
3500
Precious stone
Zinc
7000
Zinc is found in cells throughout the body.
Iron
7870
Used since ancient times
Cobalt
8900
Found in the Earth's crust only in chemically combined form
Nickel
8900
Silvery-white lustrous metal
copper
8940
Very high thermal and electrical conductivity
Silver
10500
Highest electrical conductivity, thermal conductivity
Lead
11340
Soft, malleable, and heavy metal
Mercury
13546
Only metallic element that is liquid at room temperature
Uranium
18800
weakly radioactive because all its isotopes are unstable
Iridium
22420
Densest naturally occurring element
Osmium
22570
Densest naturally occurring element


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