You have a 2.00 kg block of lead. Lead melts at 327.5°C. Cpb = 130.0 J/kg*C and ?Hj for lead is 2.04x10^4 J/kg . Say you start at room temperature (25.0°C). How much heat must you transfer to melt all the lead?

Answers

Answer 1

Answer:

Answer:

$1.2\cdot 10^5 J$

Explanation:

1) First of all, we need to calculate the heat needed to raise the temperature of the block of lead from the initial temperature (25.0 C) to the melting temperature (327.5 C). This heat is given by the equation

$Q_1 = m C_(pb) \Delta T$

where

m = 2.00 kg is the mass of the block

Cpb = 130.0 J/kg*C is the specific heat capacity of lead

$\Delta T=327.5 C-25.0 C=302.5 C$ is the temperature difference

Substituting,

$Q_1 = (2.00 kg) (130 J/kgC) (302.5 C)=7.87\cdot 10^4 J$

2) Now we have to calculate the amount of heat needed to completely melt the lead, which is given by:

$Q_2 = m Hj$

where

Hj = 2.04x10^4 J/kg is the latent heat of fusion of lead

Substituting,

$Q_2 = (2.00 kg)(2.04\cdot 10^4 J/kg)=4.08\cdot 10^4 J$

3) Therefore, the total heat needed is

$Q=Q_1+Q_2=7.87\cdot 10^4 J+4.08\cdot 10^4 J=1.2 \cdot 10^5 J$

Answer 2

Answer:

Answer:

Q = 2.00kg x 130 J/kgC x 302.5C

Q = 7.87 x 10^4j

Q = 2.00kg x 2.04 x 20^4

Q= 4.08 x 10^4

Q = 7.87 x 10^4j + 4.08 x 10^4 = 1.2 x 10^5j

Explanation:

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Solve the following automotive-services problem.Voltage = 220 v
Current = 4 amps
Resistance =

Answers

Explanation:

Given that,

Voltage, V = 220 V

Current, I = 4 A

We have to find the resistance of the appliance.

Ohm's law gives the relation between the current, resistance and the voltage.

V = I R, R = resistance

So, $R=(V)/(I)$

$R=(220\ V)/(4\ A)$

$R=55\ \Omega$

Resistance of the appliance is $55\ \Omega$ .

Hence, this is the required solution.

Resistance = (voltage) / (current)

= (220 V) / (4 A) = 55 ohms .

(Where exactly do you use 220 V in your car ? ! ?)

A 70kg divers steps off of a 10m tower and drops from rest straight into the water. If he comes to rest 5m beneath the surface, determine the average resistance force exerted on him by the water.

Answers

Kinetic Energy:
K E= m g h
h = 10 m, d = 5 m.
m g ( h + d ) - F d = 0
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First, we need to calculate the total distance that the diver travelled. The diver jumped off a 10-meter tower and went 5 meters under the water. Therefore, the total distance travelled by the diver is 10 meters (from the tower) plus 5 meters (underwater), which equals 15 meters.

Next, we will determine the work done on the diver. The work done is equal to the change in potential energy, which can be calculated by multiplying the diver's mass by gravity and then by the total distance the diver travelled. Given that the diver's mass is 70kg and the acceleration due to gravity is 9.8m/s², the work done is 70kg * 9.8m/s² * 15m, which equals 10290 Joules.

Finally, we'll find the average resistance force exerted on the diver by the water. The work done on the diver is also equal to the average force times the distance. Therefore, the average force is the work done divided by the distance. When you divide the work done (10290 Joules) by the total distance travelled (15 meters), you get an average force of 686 Newtons.

Hence, the total distance travelled by the diver in water is 5 meters, the work done on the diver is 10290 Joules, and the average resistance force exerted on the diver by the water is 2058 Newtons.

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Ix identical square pyramids can fill the same volume as a cube with the same base. If the height of the cube is h units, what is true about the height of each pyramid? a.The height of each pyramid is h units.
b.The height of each pyramid is h units.
c.The height of each pyramid is h units.
d.The height of each pyramid is h units.

Answers

Answer:

height of each pyramid must be 3h units

Explanation:

As we know that the volume of the cube is same as that of volume of square pyramid

so we have volume of the cube is given as

$V = h^3$

now if the base area of pyramid and the cube is same

so we will have

$V_(pyramid) = (1)/(3) Base\: Area * height$

$V_(pyramid) = (1)/(3) h^2 * y$

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$y = 3h$

height of each pyramid must be 3h units

The transuranium synthesis process involves creating a transuranium element through ____.A.) The synthesis of heavy elements
B.) The transmutation of a lighter element
C.) The transmutation of uranium

Answers

The transuranium synthesis process involves creating a transuranium element through the transmutation of a lighter element. The answer is letter B. Transuranium elements are the elements with atomic numbers greater than 92. All of these elements are unstable and decay radioactively into other elements.

Why is carbon unique among the elements?????

Answers

Because no living organism can exist without carbon. It is the essence if life. Every single living thing that breathes or moves or produce is made up if carbon

The table lists pressure and volume values for a particular gas. Which is the best estimate for the value of V at P = 7.0 × 103 pascals? P (pascals) V (liters) 5.0 × 103 6.0 1.5 × 104 3.0 2.0 × 104 2.0 2.5 × 104 1.5

Answers

Answer:

17.23L

Explanation:

The table lists pressure and volume values for a particular gas. Which is the best estimate for the value of V at P = 7.0 × 103 pascals?

P (pascals) V (liters) 1/v

1. 5.0 × 10^3 6.0 0.16

2. 1.5 × 10^4 3.0 0.33

3. 2.0 × 10^4 2.0 0.5

4. 2.5 × 10^4 1.5 0.66

if we are to plot the above data in a linear graph, the equation of a line graph below can be used

y-y1=m(x-x1)

y-y1= $(y2-y1)/(x2-x1)$ (x-x1)..............1

from the ideal gas law

pressure is inversely proportional to volume as nRT is the constant of proportionality

PV=nRT

P=nRT/V

from equation 1

let y1= 1.5 × 10^4

y2= 2.0 × 10^4

x1=0.33

x2= 0.5

y-1.5x10^4=2.0 × 10^4-1.5 × 10^4 /(0.5-.33)(x-0.33)

y-1.5x10^4=29411(x-0.33)

y=15000-9705.88+29411x

y=5294+29411x

at 7*10^3

7*10^3=5294+29411x

x=0.058

recall that x=1/V

inverse of both sides gives volume to be

V=17.23L

I think the question need to use extrapolation. FInd the linear function of the first and second data. And then, the anwser is 5.4 liters.

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