Английский язык. Кислякова Н.В - 5 стр.

                                          5
by distillation. The term “alcohol” without qualification means ethanol. The term
ether is used for diethyl ether. When the alcohol content is defined in preparations
the term “per cent” is used for the volume per cent of alcohol.
         The molecular masses of compounds described in Pharmacopoeia are
calculated according to the table of relative atomic masses adopted in 1975 by
International Union of Pure and Applied Chemistry (IUPAC) and based on the
carbon scale 12. If the molecular mass is under (or less than) 400 bring two
decimal points if it is above (or over) 400 – one decimal point.
         Weighing on analytical balance to within 0,0002 g means exact werghing.
If the exact weighing is not indicated, it should be taken to within 0.01 g.
         The term “constant mass” is applied to the definition of weight losses in the
process of drying or when defining the sulfate ash. It means that the difference in
mass between the two weighings doesn’t exceed 0.0005 g. The second weighing is
made after the additional 1-hour period of drying or ignition.
         Test on the absence of odour in the preparation is carried out immediately
after opening the package 1-2 g. of preparation are distributed equally on the watch
glass. 6-8 cm in diameter and in 2 min one should smell the odour at the distance
of 4-6 cm from the watch glass.
         The dropper should be used to count drops. It gives twenty drops in 1 ml at
   0
20 C.
         Vocabulary practice
         II. Read the text again and say whether the following statements are true or
false. Use such expressions as:
    1. The terms “cold”, “cool” correspond to the t0 range of 120-150 C.
    2. When solvent is not specified for the solution, then aledcol is meant.
    3. If the molecular mass is under 400, bring you should bring one decimal
       point.
    4. Weighing on analytical balance to within 0,0002 is called exact weighing.
    5. While defining the weight losses, the second weighing is made immediately
       after the first one.
    6. Test on the absence of odour is carried out 2 hours after opening the
       package.
    7. The dropper is used count drops.
          IV. Find out the Russian equivalents of the following English derivatives.
Complete the sentences with an appropriate derivative.
A. solubility                   to dissolve


                solution


   solvent                    soluble