I think the answer is 4 carbon dioxide
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:
D
Explanation:
The correct thing to do in this case would be to <u>repeat the experiment.</u>
The scientist would need to repeat the experiment in order to double-check the accuracy. If the accuracy is indeed doubtful, he/she can be able to trace the source of the error by repeating the experiment.
The correct option is D.
Answer:
978mmHg
Explanation:
The total pressure of a gas mixture is defined as the sum of the pressure of each gas in the mixture.
If the mixture of gases you have 200mmHg for O₂, 350mmHg for N₂ and 428mmHg for He, total pressure of the mixture is:
200mmHg + 350mmHg + 428mmHg = <em>978mmHg</em>
The answer is a bc it decreases
