Which of the following speeds is greatest? (2.54 cm = 1.00 in.)

a/ Compute the quantity of heat released by 25.0 g of steam initially at 100.0oC, when it is cooled to 34.0°C and by 25.0 g of w

Svetach [21]

Answer:

When put into steam

Explanation:

When a certain amount of steam at boiling temperature condenses (turning into water), the amount of heat released is

$Q_1 = m\lambda_v$

where in this case

m = 25.0 g = 0.025 kg is the mass of steam at 100.0°C

$\lambda_v=2.256\cdot 10^6 J/kg$ is the latent heat of vaporization of water

So,

$Q_1=(0.025)(2.256\cdot 10^6)=56400 J$

Instead, the amount of heat released when the water at 100.0°C is cooled down to 34.0°C is given by

$Q_2=mC\Delta T$

where

m = 25.0 g = 0.025 kg is the mass of water

$C=4.19\cdot 10^4 J/kg K$ is the specific heat of water

$\Delta T=100-34=66^{\circ}C$ is the change in temperature

Therefore,

$Q_2=(0.025)(4.19\cdot 10^3)(66)=6913 J$

Since $Q_1>Q_2$ , we can say that your hand will burn more in the first case.

5 0

3 years ago

The biological roles of complex organic molecules are determined by their shape -- the way atoms and electrons create charge dis

Hatshy [7]

Answer:

a) P_α = exp (-ΔE / kT), b) P_β = 0.145 , d) ΔE = 309.7 meV

Explanation:

The expression for the number of molecules or particles in a given state in Boltzmann's expression

n = n₀ exp (-ΔE / kT)

Where k is the Bolztmann constant and T the absolute temperature

The probability is defined as the number of molecules in a given state over the total number of particles

P = n / n₀ = exp (- ΔE / kT)

Let's apply this expression to our case

a) P_α = n_α / n₀ = exp (-ΔE / kT)

b) the Boltzmann constant

k = 1,381 10⁻²³ J / K (1 eV / 1.6 10⁻¹⁹ J) = 8.63 10⁻⁵ eV / K

kT = 8.63 105 300 = 2,589 10⁻² eV

P_β = exp (- 50 10⁻³ /2.589 10⁻² = exp (-1.931)

P_β = 0.145

c) If the temperature approaches absolute zero, the so-called is very high, so there is no energy to reach the excited state, therefore or all the molecules go to the alpha state

d) For molecules to spend ¼ of the time in this beta there must be ¼ of molecules in this state since the decay is constant.

P_β = ¼ = 0.25

P_β = exp (- ΔE / kT)

ΔE = -kT ln P_β

ΔE = - 2,589 10⁻² ln 0.25

ΔE = 0.3097 eV

ΔE = 309.7 meV

3 0

3 years ago

After giving an intense performance, a confused and disoriented ﬂautist has wandered onto the motorway! They are playing a con

leva [86]

This is a Doppler effect. Generally, if you move to a frequency source, you would detect an increase in frequency and when you move away from a source you would detect a decrease.

For this question, before you pass them, you are actually approaching them, so you would hear a higher frequency than the constant 300 Hz they are playing at.

Using the condensed formula:

f ' = ((v <u>+</u> vd)/(v <u>+</u> vs)) * f

Where: vd = Velocity of the detector.
   vs = Velocity of the frequency source.
   v = Velocity of sound in air.
   f ' = Apparent frequency.
   f = Frequency of source.

v = 343 m/s, vd = detector = 27.8 m/s, vs = velocity of the source =0. (the flautists are not moving).
f = 300 Hz.

There would be an overall increase in frequency, so we maintain a plus at the numerator and a minus at the denominator.

f ' = ((v + vd)/(v - vs)) * f

f ' = ((343+ 27.8)/(343 - 0)) * 300
   = (370.8/343)* 300 = 324.3

Therefore frequency before passing them = 324.3 Hz.

Cheers.

4 0

3 years ago

The temperature of a smelting furnace is found to be 2000 ℃. Find the

IRISSAK [1]

Answer:

a) The equivalent temperature of 2000 ºC is 3632 ºF.

b) The equivalent temperature of 2000 ºC is 4091.67 R.

c) The equivalent temperature of 2000 ºC is 2273.15 K.

d) The equivalent temperature of 2000 ºC is 1600 ºRe.

Explanation:

a) The equivalent temperature on the Fahrenheit scale is defined by the following formula:

$T_{F} = \frac{9}{5}\cdot T_{C}+32$ (Eq. 1)

Where:

$T_{C}$ - Temperature, measured in degrees Celsius.

$T_{F}$ - Temperature, measured in degrees Fahrenheit.

If we know that $T_{C} = 2000\,^{\circ}C$ , then the temperature is:

$T_{F} = \frac{9}{5}\cdot (2000\,^{\circ}C)+32\,^{\circ}F$

$T_{F} = 3632\,^{\circ}F$

The equivalent temperature of 2000 ºC is 3632 ºF.

b) From result in a) we determine the equivalent temperature on the Rankine scale by using the following formula:

$T_{R} = T_{F}+459.67$ (Eq. 2)

Where:

$T_{F}$ - Temperature, measured in degrees Fahrenheit.

$T_{R}$ - Temperature, measured in Rankine.

If we know that $T_{F} = 3632\,^{\circ}F$ , then the temperature is:

$T_{R} = 3632\,^{\circ}F+459.67\,R$

$T_{R} = 4091.67\,R$

The equivalent temperature of 2000 ºC is 4091.67 R.

c) The equivalent temperature on the absolute scale is calculated by using this expression:

$T_{K} = T_{C}+273.15$ (Eq. 3)

Where:

$T_{C}$ - Temperature, measured in degrees Celsius.

$T_{K}$ - Temperature, measured in Kelvin.

If we know that $T_{C} = 2000\,^{\circ}C$ , then the temperature is:

$T_{K} = 2000\,^{\circ}C+273.15\,K$

$T_{K} = 2273.15\,K$

The equivalent temperature of 2000 ºC is 2273.15 K.

d) The equivalent temperature on the Réaumur scale is calculated by applying this expression:

$T_{Re} = \frac{4}{5}\cdot T_{C}$ (Eq. 4)

Where:

$T_{C}$ - Temperature, measured in degrees Celsius.

$T_{Re}$ - Temperature, measured in degrees Réaumur.

If we know that $T_{C} = 2000\,^{\circ}C$ , then the temperature is:

$T_{Re} = \frac{4}{5}\cdot (2000\,^{\circ}C)$

$T_{Re} = 1600\,^{\circ}Re$

The equivalent temperature of 2000 ºC is 1600 ºRe.

5 0

3 years ago

What role will robots play in our future?

Setler [38]

It depends on what robots are in our future. Robots could even be the future.

8 0

3 years ago

Read 2 more answers