Answer:
744.9 mmHg ≅ 745 mmHg
Explanation:
The base to solve this, is the Ideal Gases Law. The mentioned formula is:
P . V = n . R . T
To compare two situations, we can propose:
For the first situation P₁ . V₁ = n₁. R . T₁
For the second situation P₂ . V₂ = n₂ . R . T₂
As the sample has the same moles and R is a constant value, we can avoid them so: (P₁ . V₁) / T₁ = (P₂ . V₂) / T₂
We need to make Tº unit conversion:
25ºC + 273 = 298K
We replace data → (370 mL . 1020 mmHg) / 298K = (P . 510 mL) / 300 K
(377400 mL.mmHg / 298K) . 300 K = P . 510 mL
379932.8 mL . mmHg = P . 510 mL
(379932.8 mL . mmHg) / 510 mL = P → 744.9 mmHg
Answer:
from nitrogen fixation in plants, lightning and bacteria
Explanation:
The reaction of acid, assuming HCl and calcium carbonate always produces a gas. The reaction is as follows:
2 HCl + CaCO3 --> CaCl2 + H2CO3
H2CO3, carbonic acid, is a weak acid that is unstable in water solutions at high concentrations. As such, it decomposes:
H2CO3 --> H2O + CO2
Then,
2 HCl + CaCO3 --> CaCl2 + H2O + CO2
The total ionic equation looks as follows:
2H+(aq) + 2 Cl-(aq) + CaCO3(s) --> Ca+2(aq) + 2 Cl-(aq) + H2O(l) + CO2(g)
Clearly, Cl- is a spectator ion as it is unchanged in the reaction. The net ionic reaction looks as follows:
2 H+(aq) + CaCO3(s) --> Ca+2(aq) + H2O(l) + CO2(g)
Answer: D
Explanation: I got it wrong on my test :( and got this answer as correct.
Answer:-
Water is highly ordered. In water each oxygen atom is connected to others around it through hydrogen bonding via bridging hydrogen atoms. When a salt like NaCl is dissolved, some of these Hydrogen bonds break.
When a salt like NaCl dissolves in water, the NaCl breaks in to ions Na+ and Cl-.
The water molecules now surround these ions.
The slightly negative oxygen end of water molecule gets near the Na+, while the slightly positive Hydrogen of water molecule gets near the Cl-.
So before salt sample dissolve, the water molecules were highly ordered due to hydrogen bonding. Now after salt dissolve there is a decrease in order and thus an increase in disorder of the water molecules.
Due to increase in disorder, entropy which is a measure of disorder increases. Since entropy increases, delta S for the process is positive.
