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:
The answer is
<h2>720 Joules</h2>
Explanation:
The kinetic energy of a body can be found by using the formula
<h3>

</h3>
where
m is the mass
v is the velocity / speed
From the question
mass = 10 kg
velocity = 12 m/s
Substitute the values into the above formula and solve
That's
<h3>

</h3>
We have the final answer as
<h3>720 Joules</h3>
Hope this helps you
The <span>era that is know as the age of mammals is the </span><span>Mesozoic
period.
Answer: Letter D
Hope that helps. -UF aka Nadoa</span>
Answer:
The answer of the scientific STATEMENT is" Appears That Ants Live In Colonies."