Answer:
Close to the calculated endpoint of a titration - <u>Partially open</u>
At the beginning of a titration - <u>Completely open</u>
Filling the buret with titrant - <u>Completely closed</u>
Conditioning the buret with the titrant - <u>Completely closed</u>
Explanation:
'Titration' is depicted as the process under which the concentration of some substances in a solution is determined by adding measured amounts of some other substance until a rection is displayed to be complete.
As per the question, the stopcock would remain completely open when the process of titration starts. After the buret is successfully placed, the titrant is carefully put through the buret in the stopcock which is entirely closed. Thereafter, when the titrant and the buret are conditioned, the stopcock must remain closed for correct results. Then, when the process is near the estimated end-point and the solution begins to turn its color, the stopcock would be slightly open before the reading of the endpoint for adding the drops of titrant for final observation.
Answer:
The bond dissociation energy to break 4 bonds in 1 mol of CH is 1644 kJ
Explanation:
Since there are 4 C-H bonds in CH₄, the bond dissociation energy of 1 mol of CH₄ is 4 × bond dissociation energy of one C-H bond.
From the table one mole is C-H bond requires 411 kJ, that is 411 kJ/mol. Therefore, 4 C-H bonds would require 4 × 411 kJ = 1644 kJ
So, the bond dissociation energy to break 4 bonds in 1 mol of CH₄ is 1644 kJ
Answer:
3
Explanation:
A cyclic event is one that happens repeatedly.
The appearance of Hailey's Comet is a cyclic event because it has happened in various occasions in the past on a regular schedule as predicted. We have every reason to believe that the appearance of Hailey's Comet every 75 years will continue to be happen until the comet ceases to exist.
Answer:
The composition of 1-propanol in vapor phase = 11.54 %
The composition of 2-propanol in vapor phase = 88.46 %
Explanation:
Mole fraction of components in liquid phase:
1-propanol = 
2-propanol = 

Partial pressure of 1-propanol =
Partial pressure of 2-propanol =
According to Raoults law:


Mole fraction of components in vapor phase:
1-propanol = 

The composition of 1-propanol in vapor phase:
100 × 0.1154= 11.54 %
2-propanol = 

The composition of 2-propanol in vapor phase:
100 × 0.8846 = 88.46 %
Explanation:
When work is done then there will occur change in volume. And, most change in volume occurs when there will be production of gas is taking place. We assume that no work is done when no gas is produced.
(a) For 
Here, 3 moles of gas is producing 0 moles of gas. This means that work is done on the system.
(b) And, more is the production of a gas taking place in a reaction more will be the amount of work done by the system.
For 
Here, 2 moles of a gas is producing 3 moles of a gas. Since, gas is increasing so, work will be done by the system.