Exercices S'entraîner
34 Homeopathy and dilutions
Extraire et exploiter des informations; effectuer un
calcul; pratiquer une langue vivante étrangère.
Homeopathy is an alternative medicine created in
1796 by Samuel Hahnemann. He thought that a
substance that causes the symptoms of a disease¹
in healthy people will cure similar symptoms in sick
people. The remedies are prepared by repeatedly
diluting a stock solution² in alcohol or distilled water,
followed by forceful³ shaking. Hahnemann created
the "centesimal" or "C scale", diluting a substance by
a factor of 100 at each stage4.
Vocabulary : 1. disease: maladie; 2. stock solution: solution
mère; 3. forceful: énergique; 4. stage: étape.
1. What is the dilution factor that makes a 1C solution
become a 2C solution?
2. If the mass concentration of the active ingredient of
the stock solution is equal to 5,0 g L-1, what is the mass
concentration of the solution at 11C?
3. In a stock solution of arnica, the main active ingredient
is helenalin, which has anti-inflammatory properties. The
mass of helenalin molecule is: mhelenalin = 4,36 x 10-22 g.
a. Find how many helenalin molecules are contained in
a liter of 11C arnica solution prepared from the stock
solution from the question 2.
Quelqu’un peut me dire ce que 100 représente