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:
Na(s) + C(s, graphite) + 1/2 H₂(g) + 3/2 O₂(g) → NaHCO₃(s)
Explanation:
The standard formation reaction is the synthesis of 1 mole of a substance from its elements in their most stables forms under standard conditions. The balanced chemical equation is:
Na(s) + C(s, graphite) + 1/2 H₂(g) + 3/2 O₂(g) → NaHCO₃(s)
The correct answer would be C.. its ability to be graphed. I am taking this test too! hope this helps!!! :)
Answer:
The volume of the vessel is 250 L
Partial pressure of hydrogen = 189 torr
Explanation:
Using Boyle's law
Given ,
V₁ = 20.0 L
V₂ = ?
P₁ = 25 atm
P₂ = 2 atm
Using above equation as:
<u>The volume of the vessel is 250 L.</u>
According to Dalton's law of partial pressure:-
So, according to definition of mole fraction:
Also,
Mole fraction of H₂ = 1 - Mole fraction of He = 1 - 0.75 = 0.25
So,
Total pressure = 756 torr
Thus,
<u>Partial pressure of hydrogen = 189 torr.</u>
