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3 years ago

A balloon filled with helium occupies 20.0 l at 1.50 atm and 25.0◦

1 answer:

5 0

At stp (standard temperature and pressure), the temperature is T=0 C=273 K and the pressure is p=1.00 atm. So we can use the ideal gas law to find the number of moles of helium:
$pV=nRT$
where p is the pressure (1.00 atm), V the volume (20.0 L), n the number of moles, T the temperature (273 K) and $R=0.082 atm L K^{-1} mol^{-1}$ the gas constant. Using the numbers and re-arranging the formula, we can calculate n:
$n= \frac{pV}{RT}= \frac{(1.00atm)(20.0L)}{(0.082 LatmK^{-1}mol^{-1})(273 K)}=0.89 mol$

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The motor in a refrigerator has a power output of 400 W. If the freezing compartment is at 273 K and the outside air is at 306 K

Aleksandr [31]

Answer:15,883.63 KJ

Explanation:

Given

Power=400 W

Freezing compartment temperature is 273 K $(T_L)$

Outside air Temperature=306 K $(T_H)$

Time =80 minutes

Energy Required to deliver 400 w power in 80 minutes

E=1920 KJ

and we know COP of refrigerator is given by

$COP=\frac{T_L}{T_H-T_L}$ $=\frac{Desired\ effect}{Work}$

$\frac{273}{306-273}=\frac{D.E.}{1920}$

$D.E.=8.27\times 1920=15883.63 KJ$

Therefore 15,883.63 KJ is removed in 80 minutes

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3 years ago

At NASA's Zero Gravity Research Facility in Cleveland, Ohio, experimental payloads fall freely from rest in an evacuated vertica

Diano4ka-milaya [45]

Answer:

(a). Energy is 64,680 J

(b) velocity is 51.43m/s

Explanation:

(a).

The potential energy $P$ of the payload of mass $m$ is at a vertical distance $h$ is

$P =mgh$ .

Therefore, for the payload of mass $m = 50kg$ at a vertical distance of $h = 132 m$ , the potential energy is

$P = (50kg)(9.8m/s^2)(132m)$

$\boxed{P = 64,680J}$

(b).

When the payload reaches the bottom of the shaft, all of its potential energy is converted into its kinetic energy; therefore,

$mgh= \dfrac{1}{2}mv^2$

$v= \sqrt{2gh}$

$v = \sqrt{2*9.8*135}$

$\boxed{v = 51.43m/s}$

(c).

The velocity in mph is

$\dfrac{51.43m}{s} * \dfrac{3600s}{hr} * \dfrac{1mile}{1609.34m}$

$\boxed{v= 115.0mph}$

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3 years ago

A 0.010 kg clay ball thrown right at 16 m/s hits a marble moving left at 8.0 m/s, and sticks to it. Both move left at 3.2 m/s af

Anettt [7]

.……… it will be 7.5m/s

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3 years ago

Read 2 more answers

Why is silicon needed in solar panels?

kodGreya [7K]

Hi, silicon is essential in solar panels because, silicon is a semiconductor material (meaning a solid substance that has a conductivity of an insulator and is an essential component of most electric circuits ) now, when dipped with impurities such as gallium and arsenic it has the ability to capture the suns energy and convert to electricity. hope this is helpful if it is than put a thank you plz.

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3 years ago

An electron that has an instantaneous velocity of ???? = 2.0 × 106 m ???? ???? + 3.0 × 106 m ???? ???? is moving through the uni

Setler79 [48]

Explanation:

It is given that,

Velocity of the electron, $v=(2\times 10^6i+3\times 10^6j)\ m/s$