This name is phosphine flammable , toxic gas colourless
...it's formula is PH3
Answer: The standard enthalpy of formation of liquid octane is -250.2 kJ/mol
Explanation:
The given balanced chemical reaction is,
First we have to calculate the enthalpy of reaction 
.
![\Delta H^o=[n_{O_2}\times \Delta H_f^0_{(O_2)}+n_{H_2O}\times \Delta H_f^0_{(H_2O)}]-[n_{C_8H_{18}}\times \Delta H_f^0_{(C_8H_{18})+n_{O_2}\times \Delta H_f^0_{(O_2)}]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo%3D%5Bn_%7BO_2%7D%5Ctimes%20%5CDelta%20H_f%5E0_%7B%28O_2%29%7D%2Bn_%7BH_2O%7D%5Ctimes%20%5CDelta%20H_f%5E0_%7B%28H_2O%29%7D%5D-%5Bn_%7BC_8H_%7B18%7D%7D%5Ctimes%20%5CDelta%20H_f%5E0_%7B%28C_8H_%7B18%7D%29%2Bn_%7BO_2%7D%5Ctimes%20%5CDelta%20H_f%5E0_%7B%28O_2%29%7D%5D)
where,
We are given:
Putting values in above equation, we get:
![-1.0940\times 10^4=[(16\times -393.5)+(18\times -285.8)]-[(25\times 0)+(2\times \Delat H_f{C_8H_{18}(l)}]](https://tex.z-dn.net/?f=-1.0940%5Ctimes%2010%5E4%3D%5B%2816%5Ctimes%20-393.5%29%2B%2818%5Ctimes%20-285.8%29%5D-%5B%2825%5Ctimes%200%29%2B%282%5Ctimes%20%5CDelat%20H_f%7BC_8H_%7B18%7D%28l%29%7D%5D)
Thus the standard enthalpy of formation of liquid octane is -250.2 kJ/mol
Answer:
Explanation:
As per Boltzman equation, <em>kinetic energy (KE)</em> is in direct relation to the <em>temperature</em>, measured in absolute scale Kelvin.
Then, <em>the temperature at which the molecules of an ideal gas have 3 times the kinetic energy they have at any given temperature will be </em><em>3 times</em><em> such temperature.</em>
So, you must just convert the given temperature, 32°F, to kelvin scale.
You can do that in two stages.
- First, convert 32°F to °C. Since, 32°F is the freezing temperature of water, you may remember that is 0°C. You can also use the conversion formula: T (°C) = [T (°F) - 32] / 1.80
- Second, convert 0°C to kelvin:
T (K) = T(°C) + 273.15 K= 273.15 K
Then, <u>3 times</u> gives you: 3 × 273.15 K = 819.45 K
Since, 32°F has two significant figures, you must report your answer with the same number of significan figures. That is 820 K.
Answer:
1.65 A
Explanation:
The hydrogen gas dissociates following the equation:
H₂(g) → 2H⁺ + 2e⁻
So, for 1 mol of H₂, 2 moles of electrons are given. The current is formed because of the presence of the electrons. Thus, the number of moles of electrons is the double of the moles of hydrogen gas: 1.026x10⁻³ mol.
By the Faraday law, 1 mol of electrons produces 96500 C of charge, thus:
1 mol --------------- 96500 C
1.026x10⁻³ mol ---- x
By a simple direct three rule:
x = 99.009 C
The current is the charge divided by the time. So, for 1 min = 60 s,
i = 99.009/60
i = 1.65 A
<h3>
Answer:</h3>
30 miles per hour faster
<h3>
Explanation:</h3>
We are given;
- Distance that Mary drove as 525 miles
- Time she took as 7 hours
- Average speed as 75 miles per hour
We are supposed to determine how fast the average speed would be if she made the trip in 5 hours.
- We know that speed is given by dividing distance by time taken.
- In this case distance remained constant
Therefore, we can determine the speed when she took 5 hours
= 525 miles ÷ 5 hours
= 105 hours
Thus, the new speed would be 105 miles per hours
But, initial speed was 75 miles per hour
Therefore, she would travel 30 miles per hour faster to cover the journey in 5 hours.
