Answer:

Explanation:
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In this case, according to the given equation, it is possible to calculate the mass of oxygen by using the Dalton's law, considering that the total pressure is 850 torr and the vapor pressure of water at 30°C is 31.8 torr:

Thus, we solve for the pressure of oxygen as follows:

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The answer is A.18 let me know if you want an explanation
Well, radiation, in terms of physics, is the emission of electromagnetic waves
now, electromagnetic waves can take many different forms like visible light, radio waves, gamma radiation, ultraviolet light. Depending on its wavelength or frequency
thermal energy or heat generally takes the form of infrared light and all light is an form of electromagnetic wave
Answer: The black ball will have more mass than the white ball.
Explanation: Density of a substance is defined as the ratio of mass and volume occupied by the substance.
Mathematically,

We are given that the two balls are of same size, which means that the volume of both the balls are same. We are also given that the black ball is more dense than the white ball, which means that the black ball will have more mass.
As, 
Answer:
The number of moles of the gas is 9.295 moles or 9.30 moles
Explanation:
We use PV = nRT
Where P = 4.87 atm;
V = 67.54 L
R= 0.0821Latm/molK
T = 158 C = 158 +273 K = 431 K
the number of moles can be obtained by substituting the values in the respective columns and solve for n
n = PV / RT
n = 4.87 * 67.54 / 0.0821 * 431
n = 328.9198 / 35.3851
n = 9.295moles
The number of moles is approximately 9.30moles.