does anyone know the substance that should be used for the experiment where you have1ml of 1% concentrated substance(im going to call it substance X) in a test tube, you add 9ml distilled water, mix and subract 1ml from the test tube with a pipette.you empty the pipette into test tube 2 and add 2 drops of iodine to test tube 1. you repeat this for about 5 test tubes and then test how strong the colour is. it was a practical i did in biology but i can't remember the name of it.
i'm supposed to write a method for it but can't remember what substance we were using.
if anyone managed to make sense of what i just said, could you please help me out?
2007-09-29 09:06:03 · 4 answers · asked by fangs*and*venom 2 in Science & Mathematics ➔ Biology
The method you're using is a serial dilution.
Substance X could be almost anything that would respond to an indicator. Below is a website that provides tests for all sorts of chemicals. Detection, and intensity of color change, is based on concentration.
2007-09-29 13:38:23 · answer #1 · answered by Hecate109 3 · 0⤊ 0⤋
Iodine turns black or blue when mixed with starch. Iodine also interacts with Vitamin C, and in certain ways you could test for Vitamin C in a liquid by mixing starch and then dripping iodine in until it turns a different color.
2007-10-06 15:24:52 · answer #2 · answered by Anonymous · 0⤊ 0⤋
iodine tests for starch. it becomes a black/blue color in presence of starch
when you repeat, im assuming u meant you also repeat diluting the original test tube so that the last test tube is least concentrated, and therefore the lightest in color.
2007-09-29 16:49:49 · answer #3 · answered by echinate 3 · 0⤊ 0⤋
It is Horrock`s test to decide chlorine content needed to sterilise water. I am not sure.
echinate is right. Thank her
2007-09-29 17:08:37 · answer #4 · answered by J.SWAMY I ఇ జ స్వామి 7 · 0⤊ 0⤋