Chemistry exam?

Usage examples of assay.

This shows that ferric acetate liberates iodine under the conditions of the assay.

The precipitate of ammonic-magnesic phosphate is filtered off, dissolved, and titrated with uranium acetate, using the same standard solution as is used in the arsenic assay: 0.

When the lead in the assay has been separated as sulphate and dissolved in sodic acetate, less chromate is apparently required, and in this case it will be necessary to precipitate the lead in the standard with an equivalent of sodic sulphate and redissolve in sodic acetate just as in the assay.

Again, if the ore is washed with water before treating with cyanide on the large scale, then the assay should be made of the acidity of the ore after a similar washing.

It may happen that with an unknown ore the first assay will be more or less unsatisfactory: but from it the necessity for adding more or less flour will be learnt, and a second assay, with the necessary modification of the charge, should give a good result.

If this is not satisfactory repeat the assay, adding an extra gram of nitre for each 4 grams of lead in excess of that required, or 1 gram of flour for a 12-gram deficiency.

In systematic assays of this kind, the alkalinity would no doubt be generally in excess of that required by the cyanide present: there would be no inconvenience in recording such excess in terms of potassium cyanide.

If the substance to be assayed is an alloy of silver and copper, first cupel 0.

Since the 20 grams assayed was 1-20th of the whole, 1-20th part of the 0.

Suppose the bullion being assayed varies only a little, up or down, from 900 gold and 100 copper in the thousand, and that .

The further precaution that if any dross be on the surface of the metal it shall be skimmed off and separately sampled and assayed is almost too obvious to require mention.

In each case the titration must be preceded by an exact preparation of the solution to be assayed in order that the iron may be in the right state of oxidation.

The sample is taken wet as it arrives at the smelting house, and is assayed direct.

Gold from the pages of the Bible, down through the ages, to the hull of that ship, and thence to the samples that I have assayed in my laboratory in the Tower of London.

There were still goods to be assayed and shipped, miners to be fed and medicated and entertained, remnants of businesses to be tended, and most of the people remaining on Tundra gathered in Klondike, a once-prosperous city.