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4 years ago

Why do solids have a definite shape and volume.?

Physics

1 answer:

Svetlanka [38]4 years ago

5 0

It is because the Inter-nuclear distance between them is too small and they have a stable thermal temperature....

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Arsine, ash3 is a highly toxic compound used in the electronics industry for the production of semiconductors. its vapor pressur

Natalka [10]

Answer: a. 17.7 KJ/Mol

b. T=210K

Explanation:

Arsine, ash3 is a highly toxic compound used in the electronics industry for the production of semiconductors. its vapor pressure is 35 torr at – 111.95°c and 253 torr at – 83.6°c. using these data calculate.

the question isnt completely originally, but we could look at the likely derivation from the questions

(a) the standard enthalpy of vaporization

using the clausius clapeyron equation

In (PT1vap / PT2vap) = delta H (vap) / R ( (1/T1) - (1/T2) )

In (35Torr/253Torr) = delta H (vap) / 8.3145 ( (1/189.55) - (1/161.2) )

Therefore, Delta H (vap) = 17.7 KJ/Mol

b. Also the boiling point

What is the normal boiling point of arsine?

At the boiling point Pvap = atmospheric pressure = 1 atm=760 torr

substitution into the equation as stated in question 1

ln(760/253)=17700/8.314(1/189.55-1/T)

T=210K

5 0

3 years ago

Summarize how the sign of the charge affects the direction of the force (attraction or repulsion) in two complete sentences or m

Oksi-84 [34.3K]

Unlike charges attract .
like charges repel .

There are two types of charges

Namely :

positive
negative

On loosing electrons , a neutral body acquires positive charge .

On gaining electrons , a neutral body acquires negative charge .

The amount of charge present in a body , either positive or negative , is expressed in terms of an integral number of charge of an electron , which is considered the elementary entity of an electric charge .

5 0

4 years ago

shows a conical pendulum, in which the bob (the small object at the lower end of the cord) moves in a horizontal circle at const

Contact [7]

Answer:

a) $T=0.40 N$

b) $T=1.9 s$

Explanation:

Let's find the radius of the circumference first. We know that bob follows a circular path of circumference 0.94 m, it means that the perimeter is 0.94 m.

The perimeter of a circunference is:

$P=2\pi r=0.94$

$r=\frac{0.94}{2\pi}=0.15 m$

Now, we need to find the angle of the pendulum from vertical.

$tan(\alpha)=\frac{r}{L}=\frac{0.15}{0.90}=0.17$

$\alpha=9.44 ^{\circ}$

Let's apply Newton's second law to find the tension.

$\sum F=ma_{c}=m\omega^{2}r$

We use centripetal acceleration here, because we have a circular motion.

The vertical equation of motion will be:

$Tcos(\alpha)=mg$ (1)

The horizontal equation of motion will be:

$Tsin(\alpha)=m\omega^{2}r$ (2)

a) We can find T usinf the equation (1):

$T=\frac {mg}{cos(\alpha)}=\frac{0.04*9.81}{cos(9.44)}=0.40 N$

We can find the angular velocity (ω) from the equation (2):

$\omega=\sqrt{\frac{Tsin(\alpha)}{mr}}=3.31 rad/s$

b) We know that the period is T=2π/ω, therefore:

$T=\frac{2\pi}{\omega}=\frac{2\pi}{3.31}=1.9 s$

I hope it helps you!

8 0

3 years ago

Find the wavelength of a photon which has 500.0 eV of energy.

jekas [21]

Answer:

2.5 x 10⁻⁹ m

Explanation:

E = Energy of photon = 500 eV = 500 x 1.6 x 10⁻¹⁹ J

c = speed of photon = 3 x 10⁸ m/s

λ = wavelength of photon = ?

Energy of photon is given as

$E = \frac{hc}{\lambda }$

inserting the values

$500\times 1.6\times 10^{-19} = \frac{(6.63\times 10^{-34})(3\times 10^{8})}{\lambda }$

λ = 2.5 x 10⁻⁹ m

5 0

4 years ago

A car is moving at a initial velocity of 20 meters per second accelerates at a rate of 1.5 meters per second squared for 4 secon

Brrunno [24]

Answered using calculus.
Antidifferentiated the acceleration to get velocity. Added variable c as we do not know if there was an extra number there yet.
Knowing that when time is 0, the velocity is 20, we can substitute those numbers into the equation and find that c = 20.
Now we have full velocity equation: v = 1.5t + 20
Now we substitute 4 into t to find out the velocity after 4 seconds. This gives us the final answer of 26m/s

5 0

4 years ago