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2 years ago

2. The water is then heated to its boiling point. Calculate the specific latent heat of

Physics

1 answer:

Law Incorporation [45]2 years ago

6 0

Answer:

2465 J/g

Explanation:

The amount of energy required to boil a sample of water already at boiling point is given by

$Q=m\lambda_v$

where

m is the mass of the water sample

$\lambda_v$ is the specific latent heat of vaporization of water

In this problem, we know

$Q=813,600 J$

$m = 330 g$

Solving the equation for $\lambda_v$ , we find

$\lambda_v = \frac{Q}{m}=\frac{813600}{330}=2465 J/g$

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Suppose the gas resulting from the sublimation of 1.00 g carbon dioxide is collected over water at 25.0◦c into a 1.00 l containe

AlexFokin [52]

Answer:

0.56 atm

Explanation:

First of all, we need to find the number of moles of the gas.

We know that

m = 1.00 g is the mass of the gas

$Mm=44.0 g/mol$ is the molar mass of the carbon dioxide

So, the number of moles of the gas is

$n=\frac{m}{M_m}=\frac{1.00 g}{44.0 g/mol}=0.023 mol$

Now we can find the pressure of the gas by using the ideal gas equation:

$pV=nRT$

where

p is the pressure

$V=1.00 L = 0.001 m^3$ is the volume

n = 0.023 mol is the number of moles

$R=8.314 J/mol K$ is the gas constant

$T=25.0^{\circ}+273=298 K$ is the temperature of the gas

Solving the equation for p, we find

$p=\frac{nRT}{V}=\frac{(0.023 mol)(8.314 J/mol K)(298 K)}{0.001 m^3}=5.7 \cdot 10^4 Pa$

And since we have

$1 atm = 1.01\cdot 10^5 Pa$

the pressure in atmospheres is

$p=\frac{5.7\cdot 10^4 Pa}{1.01\cdot 10^5 Pa/atm}=0.56 atm$

5 0

2 years ago

16. A 7500 kg 18-wheeler traveling at 20 m/s exits onto the runaway truck ramp on the freeway.

miskamm [114]

Answer:

765,000 Joule

Explanation:

Principle of Conservation of Energy

The total energy in an isolated system cannot be created or destroyed, but transformed. Moving objects have kinetic energy, objects placed in some height above a reference level have gravitational potential energy. When they change their motion variables, one energy converts into the other, but if the numbers don't fit, we know there was some other type of energy acting into the system. The most common reason for energy 'losses' is the thermal energy, produced when objects move in rough surfaces or take friction from the air.

The 7,500 kg truck is originally traveling at 20 m/s to a certain height we'll set to 0. Thus, its total energy is

$\displaystyle E_1=\frac{mv^2}{2}$

$\displaystyle E_1=\frac{7,500\ 20^2}{2}$

$E_1=1,500,000\ Joule$

When it comes to a stop, its speed is 0 and its height is 10 m higher than before. It means all the kinetic energy was transformed into other types of energy. The gravitational potential energy is

$U=mgh=(7,500)(9.8)(10)=735,000\ Joule$

Since this number is not equal to the previous value of the energy, the difference is due to thermal energy dissipated by friction

$E_t=1,500,000\ Joule-735,000\ Joule=765,000\ Joule$

7 0

2 years ago

Suppose we replace the mass in the video with one that is four times heavier. How far from the free end must we place the pivot

Llana [10]

We must place the pivot to keep the meter stick in balance at 90 cm (10 cm from the weight) from the free end.

Answer: Option B

Explanation:

In initial stage, the meter stick’s mass and mass hanged in meter stick at one end are same. Refer figure 1, the mater stick’s weight acts at the stick’s mid-point.

If in case, the meter stick is to be at balanced form, then the acting torques sum would be zero. So,

$m \times g \times(x)+((m \times g)(x-50 \mathrm{cm}))=0$