In precipitation, you can add a chemical to a solution and observe what precipitate forms.
Acid/base tests
will tell you the pH of the substance and whether it is an acid, base or neutral substance. Flame tests are used to identify ions based on the color the flames emit.
How do you identify an unknown substance in chemistry?
- Smell: Most chemists can identify solvents by their distinctive smells (though this is a pretty bad idea). 1
- Melting point: If you’ve got very pure crystals, you can use their melting point to figure out which of several possible chemicals you’ve got.
How do you identify a chemical solution?
Learn to identify it using one of the following methods:
through precipitation
, using conduction, using a flame test, using an acid-base indicator and observing the color of the solution.
How can you identify an unknown liquid?
When
the liquid has reached its boiling temperature
, you will observe a large number of boiling bubbles in the unknown liquid and the temperature should remain fairly stable. Record this temperature as the boiling point temperature. Do not boil until the test tube is dry on the inside!
How do you find the unknown solution?
A titration is a technique where a solution of known concentration is used to determine the concentration of an unknown solution. Typically, the titrant (the know solution) is added from a buret to a known quantity of the analyte (the unknown solution) until the reaction is complete.
What was the unknown solution?
A titration is a technique where a solution of known concentration is used to determine the concentration of an unknown solution. Typically, the titrant
How do you identify a solution?
- Identify the issue.
- Explain how people tried to resolve it or how it was actually resolved.
- Recognize which details expand on the problem, which expand on the solution and which ones are not important to the main idea of the text.
What tests were used to identify unknown substances?
- Gas Chromatography (GC)
- Gas Chromatography Mass Spectroscopy (GC-MS)
- Ion Chromatography (IC)
- High Performance Liquid Chromatography (HPLC)
- Dispersive Raman Spectroscopy.
- Fourier Transfer Infrared Spectroscopy (FTIR)
What is an unknown sample?
Unknown/questioned sample –
evidence of unknown origin
; these samples could be found at a crime scene, transferred to an offender during commission of a crime, or recovered from more than one crime scene.
What is the most accurate way to identify an unknown substance?
Raman is a highly effective method for reliable identification of an unknown substance based on its underlying chemistry.
How do you test if a liquid is water?
A very easy solution is to
take a sample of colourless liquid and put on stove if it starts boiling exactly at 100 oC
then it is pure water. Any other colourless liquid such as vinegar always have different boiling point.
How can you tell what a liquid is?
- no definite shape (takes the shape of its container)
- has definite volume.
- particles are free to move over each other, but are still attracted to each other.
How do you find the density of an unknown liquid?
The mass and size of the molecules in a liquid and how closely they are packed together determine the density of the liquid. Just like a solid, the density of
a liquid equals the mass of the liquid divided by its volume
; D = m/v. The density of water is 1 gram per cubic centimeter.
Why is it important to identify unknown substances?
Identifying Unknown Substances. … In order to solve a mystery, we often need to identify poisons, gunshot residue and other substances.
Color, odor, and reaction to other substances
are unique for individual substances and can help to identify important clues.
How do you identify an anion in an unknown solution?
- dissolve a small sample of the solid salt you are testing in water.
- place approximately 10cm
3
of the solution into a test tube. - add four drops of nitric acid.
- add silver nitrate solution, dropwise.
- if a precipitate is produced, observe the colour.
How can you identify an unknown salt?
Students identify unknown chloride salts by (1)
using a precipitation reaction
to determine if the cation is a group 1 or group 2 metal, (2) performing a titration with silver nitrate to determine the formula mass of the salt, and (3) confirming the identity of the salt using a flame test.
