A spherical balloon of volume 3.92 103 cm3 contains helium at a pressure of 1.25 105 Pa. How many moles of helium are in the balloon if the average kinetic energy of the helium atoms is 3.60 10^-22 J?

3.39

Explanation:

Given that

Volume, v = 3.92*10^3 cm³ we convert the volume from cm³ to m³ and we have 0.00392

Pressure, P = 1.25*10^5 Pa

Average Kinetic Energy, K.E = 3.6*10^-22 J

We use the gas law formula,

PV = nRT

Making n subject of the formula, we have

n = PV/RT

Solving for n, we have

n = (1.25*10^5 Pa * 0.00392 m³) / 8.314 * T

n = 4.9*10^8 / 8.314 * T

n = 490 / 8.314T

n = 58.94/T

Note that average kinetic energy is given as

K.E(avg) = 3/2K.T,

3/2 K.T = 3.6*10^-22 J

where K = 1.38*10^-23

T = (3.6*10^-22 J * 2) / (3 * 1.38*10^-23)

T = 17.39

Substitute for T, we have

n = 58.94 / 17.39

n = 3.39

i would say the answer is food.

hope this !

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.