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3 years ago

PLEASE HELP ME WITH THIS ONE QUESTION

Physics

1 answer:

Kitty [74]3 years ago

6 0

Answer:

Q = 282,000 J

Explanation:

Given that,

The mass of liquid water, m = 125 g

Temperature, T = 100°C

The latent heat of vaporization, Hv = 2258 J/g.

We need to find the amount of heat needed to vaporize 125 g of liquid water. We can find it as follows :

$Q=mH_v\\\\Q=125\ g\times 2285\ J/g\\\\Q=282250\ J$

Q = 282,000 J

So, the required heat is 282,000 J .

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1. 412.9 g of dry ice sublimes at room temperature. a. What’s changing? --- sublimation b. What constant will you use? ----- 25.

hoa [83]

1. 236 kJ

a. The phase (or state of matter) of the substance: from solid state to gas state (sublimation)

b. The enthalphy of sublimation, given by: $\lambda=571 J/g$

c. The equation to use will be $Q=m\lambda$ , where m is the mass of dry ice and $\lambda$ is the enthalpy of sublimation

d. The energy is being absorbed, because the heat is transferred from the environment to the dry ice: as a consequence, the bonds between the molecules of dry ice break and then move faster and faster, and so the substance turns from solid into gas directly.

e. The amount of energy being transferred is

$Q=m\lambda=(412.9 g)(571 J/g)=2.36\cdot 10^5 J=236 kJ$

2. 165 kJ

a. The phase (or state of matter) of the substance: from gas state to liquid state (condensation)

b. The latent heat of vaporisation of water, given by $\lambda=2260 J/g$

c. The equation to use will be $Q=m\lambda$ , where m is the mass of steam that condenses and $\lambda$ is the latent heat of vaporisation

d. The energy is being released, since the substance turns from a gas state (where molecules move faster) into liquid state (where molecules move slower), so the internal energy of the substance has decreased, therefore heat has been released

e. The amount of energy being transferred is

$Q=m\lambda=(72.9 g)(2260 J/g)=1.65\cdot 10^5 J=165 kJ$

3. 3.64 kJ

a. Only the temperature of the substance (which is increasing)

b. The specific heat capacity of silver, which is $C_s = 0.240 J/gC$

c. The equation to use will be $Q=m C_s \Delta T$ , where m is the mass of silver, Cs is the specific heat capacity and $\Delta T$ the increase in temperature

d. The energy is being absorbed by the silver, since its temperature increases, this means that its molecules move faster so energy should be provided to the silver by the surroundings

e. The amount of energy being transferred is

$Q=m C_s \Delta T=(39.2 g)(0.240 J/gC)(412.9^{\circ}C-25.9^{\circ}C)=3641=3.64 kJ$

4. 89 kJ

a. Both the phase of the substance (from solid to liquid) and then the temperature

b. The latent heat of fusion of ice: $\lambda=334 J/g$ and the specific heat capacity of water: $C_s=4.186 J/gC$

c. The equation to use will be $Q=m\lambda + m C_s \Delta T$ , where m is the mass of ice, $\lambda$ the latent heat of fusion of ice, Cs is the specific heat capacity of water and $\Delta T$ the increase in temperature

d. The energy is being absorbed by the ice, at first to break the bonds between the molecules of ice and to cause the melting of ice, and then to increase the temperature of the water

e. The amount of energy being transferred is

$Q=m\lambda +m C_s \Delta T=(156.3 g)(334 J/g)+(156.3 g)(4.186 J/gC)(56.232^{\circ}C-0^{\circ}C)=8.9\cdot 10^4 J=89 kJ$

6 0

3 years ago

A dolphin keeps up with a boat for a distance of 51 miles for 3 hours. What is the dolphin’s average speed?

Sedbober [7]

Answer:

The dolphin's speed is 17 mi/h

Explanation:

Use the formula for average velocity: Distance/time

then the average speed of the dolphin is 51/3 mi/h = 17 mi/h

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4 years ago

Equation of Motion Problems

barxatty [35]

Answer:

Below in bold.

Explanation:

1. Speed = distance / time

= 100 / 9.84

= 10.16 m/s.

Speed = 200/19.32 = 10.35 m/s.

Speed = 400/43.49 = 9.20 m/s.

7 0

3 years ago

A 16.9 kg monkey is swinging on a

mrs_skeptik [129]

The potential energy of the monkey at the given position is 600.9 J.

<h3>What is potential energy?</h3>

Potential energy is the energy stored in a body that depends upon the relative position of various parts of the body.

It increases with increase in the height of the object above the ground level.

<h3>Potential energy of the monkey</h3>

The potential energy of the monkey is calculated as follows;

P.E = mgh

P.E = mg (L sin43)

where;

m is mass of the monkey, given as 16.9 kg
g is acceleration due to gravity, given as 9.8 m/s²
L is length of the vine given as 5.32 m

Substitute the given parameters and solve potential energy of the monkey

P.E = (16.9)(9.8)( 5.32 x sin 43)

P.E = 600.9 J

Thus, the potential energy of the monkey at the given position is 600.9 J.

Learn more about potential energy here: brainly.com/question/1242059

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2 years ago

Write the sequence of filling electrons in the subshell in order of increasing energy.

tankabanditka [31]

Answer:

In a way of energy “1s” subsell contains most energy. because 1 s subsell contains the electrons of K orbital which is nearest from the nucleus. so the order of energy will be 1s>2s>2p> 3s> 3p> 4s> 3d> 4p> 5s> 4d> 5p> 6s> 4f> 5d> 6p> 7s and the increasing order of thair energies will be- 4s <3d<4p<5s<4d<5p<6s<4f.

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3 years ago