Answer:
OPTION (A) : Testing a rock sample for gold content
Explanation:
For testing a rock sample of gold content you will need a Chemist. To test the material, the sample is rubbed on black stone which will leave a mark on the stone. This mark is tested by applying aqua fortis i.e nitric acid on the mark. If the mark gets dissolve then the material is not gold. If the mark sustain the it is further tested by applying aqua regia i.e nitric acid and hydrochloric acid which will prove the sample is of gold if it gets dissolve on using hydrochloric acid. The purity of the sample can be checked by differing the concentration of the aqua regia and comparing it with the gold material of the known purity.
Answer:
Biological stains are used for the medical and biological industries to aid in detection of structures within tissues. This can include the detection of abnormalities, but is not limited to that. The stains are used to define and examine cell populations within the tissues, to mark cells, or to flag proteins.
Answer:
Double replacement reaction.
Explanation:
The Na and Ag atoms both (double) trade places (replacement) with each other.
Answer:
Adding salt to the water increases the density of the solution because the salt increases the mass without changing the volume very much. When you add table salt (sodium chloride, NaCl) to water, the salt dissolves into ions, Na+ and Cl-. The volume increases by a small factor, but the mass increases by a bigger factor.
Explanation:
