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3 years ago

How much heat is absorbed by a 74g iron skillet when its temperature rises from 7oC to 28oC?

1 answer:

5 0

The specific heat of iron (assuming the skillet is pure iron) is 0.45 J/g-C. Then we use the equation q = mc(dT) to determine the total heat absorbed. This gives:
q = (74 g)(0.45 J/g-C)(28 - 7 C) = (74)(0.45)(21) = 699.3 J

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A mixture of helium and oxygen is used in scuba diving tanks to help prevent ""the bends"". 46 L helium and 12 L oxygen are comb

marin [14]

Answer

given,

For helium

Volume,V = 46 L

Pressure,P = 1 atm

Temperature,T = 25°C = 273 +25 = 298 K

R=0.0821 L . atm /mole.K

n₁ = ?

number of moles

we know

P V = n R T

$n_1 =\dfrac{46 \times 1}{0.0821\times 298}$

n₁ = 1.89 moles

For oxygen

Volume,V = 12 L

Pressure,P = 1 atm

Temperature,T = 25°C = 273 +25 = 298 K

R=0.0821 L . atm /mole.K

n₂ = ?

number of moles

we know

P V = n R T

$n_2 =\dfrac{12 \times 1}{0.0821\times 298}$

n₂ = 0.49 moles

Total volume of tank = 5 L

temperature of tank = 298 K

Partial pressure of helium

$P_1=\dfrac{n_1 R T}{V}$

$P_1=\dfrac{1.89\times 0.0821\times 298}{5}$

P₁ = 9.25 atm

Partial pressure of oxygen

$P_2=\dfrac{n_2 R T}{V}$

$P_2=\dfrac{0.49\times 0.0821\times 298}{5}$

P₂ = 2.39 atm

total pressure

P = P₁ + P₂

P = 9.25 + 2.39

P = 11.64 atm

8 0

3 years ago

Electric power plants are the main contributors of what? Oxygen pollution, Sulfur dioxide pollution, thermal pollution, mercury

zloy xaker [14]

The correct answer is sulfur dioxide pollution

Hope this helped :)

6 0

3 years ago

Read 2 more answers

Cat walks 100 m East, then turns around and walks 25 m west. What is the cats displacement?

kvasek [131]

Answer:

Explanation:

If a cat walk 100m East, this means that it is walking in the positive x direction, the distance will therefore be +100m

If it turns around and walks 25 m west, the direction of movement is in the negative x direction i.e -25m

Taking the sum;

Displacement = +100m - 25m

Displacement of the cat = 75m

hence the cats displacement is 75m

8 0

3 years ago

How can you tell if your arm is brocken?

wlad13 [49]

Well if you're experiencing severe pain obviously you can tell its broken

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3 years ago

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A convex thin lens with refractive index of 1.50 has a focal length of 30cm in air. When immersed in a certain transparent liqui

GalinKa [24]

Answer:

$n_l = 1.97$

Explanation:

given data:

refractive index of lens 1.50

focal length in air is 30 cm

focal length in water is -188 cm

Focal length of lens is given as

$\frac{1}{f} =\frac{n_2 -n_1}{n_1} * \left [\frac{1}{r1} -\frac{1}{r2} \right ]$

$\frac{1}{f} =\frac{n_{g} -n_{air}}{n_{air}} * \left [\frac{1}{r1} -\frac{1}{r2} \right ]$

$\frac{1}{f} =\frac{n_{g} -1}{1} * \left [\frac{1}{r1} -\frac{1}{r2} \right ]$

focal length of lens in liquid is

$\frac{1}{f} =\frac{n_{g} -n_{l}}{n_{l}} * \left [\frac{1}{r1} -\frac{1}{r2} \right ]$

$=\frac{n_{g} -n_{l}}{n_{l}} [\frac{1}{(n_{g} - 1) f}$

rearrange fro $n_l$

$n_l = \frac{n_g f_l}{f_l+f(n_g-1)}$

$n_l = \frac{1.50*(-188)}{-188 + 30(1.50 -1)}$

$n_l = 1.97$

7 0

3 years ago