Which of the following best describes how wireless telephones are able to receive and produce sound from one person to another?

Chemistry

1 answer:

alina1380 [7]2 years ago

8 0

Electromagnetic waves are received and then vibrate a speaker which produces sound waves.

Explanation:

The telephone has a receiver-transducer component that can receive electromagnetic wave - radio waves spectrum- and transform them into electric energy. This electric energy is then transformed into sound energy by a speaker. This is how we're able to listen to a phone call.

The opposite happens when we speak on the phone. The sound energy is transformed into electric energy by a microphone – the reverse of a speaker. The transducer now changes the electric energy into electromagnetic waves that travel through space to the recipient in the phone conversation.

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Submit At 25.0 C, a 10.00 L vessel is filled with 5.00 atm of Gas A and 7.89 atm of Gas B. What is the mole fraction of Gas B?

Firlakuza [10]

Answer:

the mole fraction of Gas B is xB= 0.612 (61.2%)

Explanation:

Assuming ideal gas behaviour of A and B, then

pA*V=nA*R*T

pB*V=nB*R*T

where

V= volume = 10 L

T= temperature= 25°C= 298 K

pA and pB= partial pressures of A and B respectively = 5 atm and 7.89 atm

R= ideal gas constant = 0.082 atm*L/(mol*K)

therefore

nA= (pA*V)/(R*T) = 5 atm* 10 L /(0.082 atm*L/(mol*K) * 298 K) = 2.04 mole

nB= (pB*V)/(R*T) = 7.89 atm* 10 L /(0.082 atm*L/(mol*K) * 298 K) = 3.22 mole

therefore the total number of moles is

n = nA +nB= 2.04 mole + 3.22 mole = 5.26 mole

the mole fraction of Gas B is then

xB= nB/n= 3.22 mole/5.26 mole = 0.612

xB= 0.612

Note

another way to obtain it is through Dalton's law

P=pB*xB , P = pA+pB → xB = pB/(pA+pB) = 7.69 atm/( 5 atm + 7.89 atm) = 0.612

5 0

2 years ago

Assuming equal concentrations of conjugate base and acid, which one of the following mixtures is suitable for making a buffer so

BartSMP [9]

Answer:

NH₃/NH₄Cl

Explanation:

We can calculate the pH of a buffer using the Henderson-Hasselbalch's equation.

$pH=pKa+log\frac{[base]}{[acid]}$

If the concentration of the acid is equal to that of the base, the pH will be equal to the pKa of the buffer. The optimum range of work of pH is pKa ± 1.

Let's consider the following buffers and their pKa.