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3 years ago

What happens to the entropy of a piece of wood as it is burned?

Physics

1 answer:

9966 [12]3 years ago

4 0

Answer: Option (a) is the correct answer.

Explanation:

Entropy is defined as the degree of randomness present in a substance. This means that more randomly the atoms in a substance are moving more will be entropy of the substance.

Entropy of a substance increases with increase in temperature.

For example, when a piece of wood is burned then its molecules will gain kinetic energy and hence, they start to move randomly from one place to another.

As a result, there will occur an increase in its entropy.

Thus, we can conclude that when a piece of wood is burned then its entropy increases.

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Taste and smell are called chemical senses because:

Bingel [31]

Answer:

The answer is a," their receptors are sensitive to chemical molecules."

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4 years ago

_______ can be generally defined as a change in position. A. Volume B. Force C. Motion D. Mass

Law Incorporation [45]

C. motion can be defined as change in position.

8 0

4 years ago

Read 2 more answers

Water evaporating from a pond does so as if it were diffusing across an air film 0.15 cm thick. The diffusion coefficient of wat

QveST [7]

Answer:

The water level will drop by about 1.24 cm in 1 day.

Explanation:

Here Mass flux of water vapour is given as

$j_{H_2O}=\frac{D}{l} \bigtriangleup c$

where

$j_{H_2O}$ is the mass flux of the water which is to be calculated.

D is diffusion coefficient which is given as $0.25 cm^2/s$

l is the thickness of the film which is 0.15 cm thick.
$\bigtriangleup c$ is given as

$\bigtriangleup c= \frac{P_{sat}-P_a}{RT}$

In this

$P_{sat}$ is the saturated water pressure, which is look up from the saturated water property at 20°C and 0.5 saturation given as 2.34 Pa

$P_a$ is the air pressure which is given as 0.5 times of $P_{sat}$

R is the universal gas constant as $8.314 kJ/kmol-K$

T is the temperature in Kelvin scale which is $20+273= 293K$

By substituting values in the equation

$\bigtriangleup c= \frac{P_{sat}-P_a}{RT} \\ \bigtriangleup c= \frac{P_{sat}-0.5P_{sat}}{RT} \\ \bigtriangleup c= \frac{0.5P_{sat}}{RT} \\ \bigtriangleup c= \frac{0.5 \times 2.34}{8.314 \times 293} \\\bigtriangleup c= 0.48 mol/m^3$

Converting $\bigtriangleup c$ into $cm^3/cm^3$

As 1 mole of water 18 $cm^3$ so

$\bigtriangleup c= 0.48 mol/m^3 \\ \bigtriangleup c= 0.48 \times 18 \times 10^{-6} cm^3/cm^3 \\ \bigtriangleup c= 8.64 \times 10^{-6} cm^3/cm^3$

Putting this in the equation of mass flux equation gives

$j_{H_2O}=\frac{D}{l} \bigtriangleup c \\ j_{H_2O}=\frac{0.25}{0.15} \times 8.64 \times 10^{-6} \\ j_{H_2O}=14.4 \times 10^{-6} cm/s$

For calculation of water level drop in a day, converting mass flux as

$j_{H_2O}=14.4 \times 10^{-6} \times 24 \times 3600 cm/day\\ j_{H_2O}=1.24 cm/day$

So the water level will drop by about 1.24 cm in 1 day.

7 0

3 years ago

The answer is A and no matter how many times I tried I can't get it.

ryzh [129]

Imagine a skinny straw in the water, standing right over the hole. The WEIGHT of the water in that straw is the force on the tape. Now, the volume of water in the straw is (1 mm^2) times (20 cm). Once you have the volume, you can use the density and gravity to find the weight. And THAT's the force on the tape. If the tape can't hold that force, then it peels off and the water runs out through the hole. /// This is a pretty hard problem, because it involved mm^2, cm, and m^3. You have to be very very very careful with your units as you work through this one. If you've been struggling with it, I'm almost sure the problem is the units.

5 0

3 years ago

The ratio of the number of pigs to the number of horse in a farm is 2 to 3 (2:3), if therected are 24 horses, what is the number

pickupchik [31]

Answer:

16 pigs

Explanation:

Let the horses be H.

Let the pigs be P

Let the total number of animals be x.

Given the following data;

Ratio of P to H = 2:3 = 2 + 3 = 5

Number of horses = 24

To find the number of pigs;

First of all, we would determine the total number of animals x.

From the ratio of horse, H:

3/5 * x = 24

Cross-multiplying, we have;

3x = 120

x = 120/3 = 40

Next, we find the number of pigs;

Pigs = 2/5 * 40

Pigs = 80/5 = 16 pigs

5 0

3 years ago