Chemical Tests Flashcards
how do you find that a substance has starch present in it ?
Add iodine solution to the sample. a color change to blue black indicates a presence of starch.
What is the chemical test for reducing sugars?
Glucose is a reducing sugar, glucose and other reducing sugars can be detected using the benedicts solution. The benedicts solution contains copper sulphate which makes it blue. When added to a sample solution and heated to 80 degrees, the Cu2+ ions are reduced to an insoluble brick red copper. Copper (l) oxide.
How do you find out that a sample solution has protein present in it?
The sample solution is placed in a test tube with an equal amount of sodium hydroxide solution. Add a few drops of dilute copper (ll) sulphate solution, if protein is present then the solution will turn purple, if it remains blue then no protein is present. This is known as the buirets test.
How do you find out that a solution contains fats & oils.
Place sample in a solution and add ethanol, shake it to dissolve any fats or oils. Add water and shake tube again, a cloudy white layer on top of solution tells us that fats or oils is present. This is known as the emulsion test.
What is the chemical test for finding out a sample contains vitamin C
Add DCPIP to a test tube which is a blue color. Add the sample and shake gently, if the solution turns colorless then vitamin C is present if it remains blue, no vitamin C is present.
What is the solution used for finding out whether a sample contains reducing sugars?
Benedicts solution
What is the test called for finding out that a sample contains proteins?
Buirets Test.
What solution do you add to a sample to find out if contains vitamin C?
DCPIP solution
The emulsion test is the chemical test to find out about which chemical?
Fats & oils
What happens to the Cu2+ ions in the copper sulphate when the sample solution is added to it and heated to 80 degrees?
The Cu2+ ions are reduced to an insoluble brick red copper. Copper (l) oxide.
