Electric charges come in two forms: positive and negative. What combinations of charges will attract and repel each other?

16 grams of ice at –32°C is to be changed to steam at 182°C. The entire process requires _____ cal. Round your answer to the nea

ICE Princess25 [194]

Answer:

12432 cal.

Explanation:

The process to change ice at -32 ºC to steam at 182 ºC can be divided into 5 steps:

1. Heat the ice to 0 ºC, which is the fusion temperature.

2. Melt the ice (obtaining liquid water), which is a process at constant pressure and temperature, so the liquid obtained is also at 0ºC.

3. Heat the liquid water from 0 ºC to 100 ºC, which is the vaporization normal temperature of the water.

4. Vaporization of all the water; this is also a process that occurs at constant pressure and temperature, so the produced steam will be at 100ºC.

5. Heat the steam from 100 ºC to 182 ºC.

Each process has a required energy, and the sum of the energy required for each and all of the steps is the total amount of energy required for the whole process:

$E_T=E_1+E_2+E_3+E_4+E_5$

$E_1$ is a heating process for the ice, so we know that the energy required is proportional to the temperature difference through the specific heat:

$E_1=m*Cp_{sol}*(T_2-T_1)\\E_1=16g*0.5\frac{cal}{gC}*(0-(-32))=256cal$

$E_2$ is a phase change process, so we do not use the specific heat (sensible heat), but the fusion heat (latent heat), so:

$E_{2}=m*dh_{f}={16g*80\frac{cal}{g}}=1280cal$

Analogously,

$E_3=m*Cp_{liq}*(T_3-T_2)=16g*1.00\frac{cal}{gC}*(100-0)C = 1600 cal$

$E_{4}=m*{dh_{vap}}\\\\E_4=16g*540\frac{cal}{g} =8640cal$

$E_{5}=m*Cp_{vap}*(T_{5}-T_{4})\\E_{5}={16g*0.5\frac{cal}{gK}*(182-100)K}=656cal$

Finally, the total energy required is:

$E_T=256cal+1280cal+1600cal+8640cal+656cal\\E_T=12432cal$

8 0

3 years ago

A particular milliampere-seconds value, regardless of the combination of milliamperes and time, will reproduce the same radiogra

finlep [7]

Answer:

C. Reciprocity law

Explanation:

The reciprocity law is based on the assumption that the density or blackening of a photographic film is dependent merely on the exposure or quantity of radiant energy which the film absorbs and is independent of the rate at which the energy is applied.

This law pertains to the milliampere-seconds in the sense that all combinations of milliamperes and time that amount to an equal quantity will produce the same amount of radiographic density.

The answer is:

C. Reciprocity law

3 0

3 years ago

This element has an atomic number that is double the atomic number of silicon

elena-14-01-66 [18.8K]

Nickel- silicon’s atomic number is 14, and nickel’s is 28

7 0

3 years ago

Briefly describe the difference between the amplitude of a wave (such as a light wave) and the frequency of light (again, such a

Mazyrski [523]

Answer:

a wave has a trough (lowest point) and a crest (highest point). The vertical distance between the tip of a crest and the wave’s central axis is known as its amplitude. This is the property associated with the brightness, or intensity, of the wave. The horizontal distance between two consecutive troughs or crests is known as the wavelength of the wave. Keep in mind that some waves (including electromagnetic waves) also oscillate in space, and therefore they are oscillating at a given position as time passes. The quantity known as the wave’s frequency refers to the number of full wavelengths that pass by a given point in space every second; the SI unit for frequency is Hertz (\text{Hz})(Hz)left parenthesis, start text, H, z, end text, right parenthesis, which is equivalent to “per seconds” \Big((left parenthesiswritten as \dfrac{1}{\text{s}} s

start fraction, 1, divided by, start text, s, end text, end fraction or \text{s}^{-1}\Big)s

−1

)start text, s, end text, start superscript, minus, 1, end superscript, right parenthesis. As you might imagine, wavelength and frequency are inversely proportional: that is, the shorter the wavelength, the higher the frequency, and vice versa. This relationship is given by the following equation:

c=\lambda \nuc=λνc, equals, lambda, \nu

where \lambdaλlambda (the Greek lambda) is the wavelength (in meters, \text{m}mstart text, m, end text) and \nuν\nu (the Greek nu) is the frequency (in Hertz, \text{Hz}Hzstart text, H, z, end text). Their product is the constant ccc, the speed of light, which is equal to 3.00\times10^8 \text{ m/s}3.00×10

8

m/s3, point, 00, times, 10, start superscript, 8, end superscript, start text, space, m, slash, s, end text. This relationship reflects an important fact: all electromagnetic radiation, regardless of wavelength or frequency, travels at the speed of light.

Explanation:

7 0

4 years ago

A trout jumps, producing waves on the surface of a 0.8-mdeep mountain stream. If it is observed that the waves do not travel ups

alina1380 [7]

Answer:

The value is $v = 2.8 \ m/s$