Answer: 996 mmHg
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at NTP, weighs equal to the molecular mass and contains avogadro's number
of particles.
According to the ideal gas equation:

P = Pressure of the gas = ?
V= Volume of the gas = 25.5 L
T= Temperature of the gas = 13°C = (273+13) K = 286K
R= Gas constant = 0.0821 atmL/K mol
n= moles of gas= 1.42
(760mmHg=1atm)
Thus pressure of this gas sample is 996 mm Hg.
Answer:
power is work/time so 10,000j/5s=2000J/s
If it is shown as ∆H , then it means that a specific chemical reaction is undergoing heat in Kelvin(K). If it is shown as ∆H° , then it means that a specific chemical reaction is undergoing heat in Celsius(C⁰).
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Answer : The final temperature of the copper is, 
Solution :
Formula used :

where,
Q = heat gained = 299 cal
m = mass of copper = 52 g
c = specific heat of copper =
= final temperature = ?
= initial temperature = 
Now put all the given values in the above formula, we get the final temperature of copper.


Therefore, the final temperature of the copper is, 
Answer:

Explanation:
Hello.
In this case, given the formula:

Whereas E is the energy, h the Planck's constant and u the frequency of the photon. Thus, solving for it, we obtain:

Or also:

Best regards.