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.
The answer is going to be A.
Answer:
3 salad = 3 lettuce + 6 tomatoes + 9 three carrots
Coefficients: 3, 6, 9
Explanation:
1 salad = 1 lettuce + 2 tomatoes + 3 three carrots
<em>Multiply all the coefficients of 1 salad by 3:</em>
3(1 salad) = 3(1 lettuce + 2 tomatoes + 3 three carrots)
<em>Expand the equation:</em>
3 salad = 3 lettuce + 6 tomatoes + 9 three carrots
A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.