Gravitational potential energy is observed when an object is not in rest or is in motion. In this case, the helicopter is in motion where the direction is going upward with a negative potential energy. Thank you for your question. Please don't hesitate to ask in Brainly your queries.
Answer:
The molecular formula of the phosphorus is P4
Explanation:
<u>Step 1:</u> Data given
Density of phosphorus vapor at 310 °C and 775 mmHg = 2.64g /L
<u>Step 2: </u>Calculate the molecular weight
We assume phosphorus to be an ideal gas
So p*V = n*R*T
⇒ with p = the pressure of phosphorus = 775 mmHg
⇒ with V = the Volume
⇒ with n = the number of moles = mass/molecular weight
⇒ with R = ideal gas constant = 0.08206 L*atm/K*mol
⇒ with T = the absolute temperature
p*V = m/MW *R*T
MW = mRT/PV
⇒ Since the volume is unknown but can be written as density = mass/volume
MW = dRT/P
MW = (2.64g/L * 0.08206 L*atm/K*mol * 583 Kelvin)/1.0197 atm
MW = 123.86 g/mol
<u>Step 3</u>: Calculate molecular formula of phosphorus
The relative atomic mass of phosphorus = 30.97 u
123.86 / 30.97 = 4
The molecular formula of the phosphorus is P4
Answer:
a. 7278 K
b. 4.542 × 10⁻³¹
Explanation:
a.
Let´s consider the following reaction.
N₂(g) + O₂(g) ⇄ 2 NO(g)
The reaction is spontaneous when:
ΔG° < 0 [1]
Let's consider a second relation:
ΔG° = ΔH° - T × ΔS° [2]
Combining [1] and [2],
ΔH° - T × ΔS° < 0
ΔH° < T × ΔS°
T > ΔH°/ΔS°
T > (180.5 × 10³ J/mol)/(24.80 J/mol.K)
T > 7278 K
b.
First, we will calculate ΔG° at 25°C + 273.15 = 298 K
ΔG° = ΔH° - T × ΔS°
ΔG° = 180.5 kJ/mol - 298 K × 24.80 × 10⁻³ kJ/mol.K
ΔG° = 173.1 kJ/mol
We can calculate the equilibrium constant using the following expression.
ΔG° = - R × T × lnK
lnK = - ΔG° / R × T
lnK = - 173.1 × 10³ J/mol / (8.314 J/mol.K) × 298 K
K = 4.542 × 10⁻³¹
Answer: 625 kj/mol
Explanation:
As shown below this expression gives the activation energy of the reverse reaction:
EA reverse reaction = EA forward reaction + | enthalpy change |
1) The activation energy, EA is the difference between the potential energies of the reactants and the transition state:
EA = energy of the transition state - energy of the reactants.
2) The activation energy of the forward reaction given is:
EA = energy of the transition state - energy of [ NO2(g) + CO(g) ] = 75 kj/mol
3) The negative enthalpy change - 250 kj / mol for the forward reaction means that the products are below in the potential energy diagram, and that the potential energy of the products, [NO(g) + CO2(g) ] is equal to 375 kj / mol - 250 kj / mol = 125 kj/mol
4) For the reverse reaction the reactants are [NO(g) + CO2(g)], and the transition state is the same than that for the forward reaction.
5) The difference of energy between the transition state and the potential energy of [NO(g) + CO2(g) ] will be the absolute value of the change of enthalpy plus the activation energy for the forward reaction:
EA reverse reaction = EA forward reaction + | enthalpy change |
EA reverse reaction = 375 kj / mol + |-250 kj/mol | = 375 kj/mol + 250 kj/mol = 625 kj/mol.
And that is the answer, 625 kj/mol
Answer:
In order to take steps by humans for controlling the change in climate.
Explanation:
It is important that scientist find out the change which occurs in the climate with the passage of time by performing experiments and also repeat the experiments in order to verify their findings. Due to these experiments, scientists also find out the reasons behind of climate change which enable us to take steps in preventing the change that occurs in the environment. it is also important for scientists to be able to explain how they know that climate has changed over time in order to explain that he is not assuming or making predictions, he has to provide evidence for his statement which is only be possible through experiments.
