This is stupid but my brain isn't working right now so im counting on someone else

How much energy must be transferred out of the system as heat q to lower its temperature to 0∘c? express your answer numerically

serg [7]

Answer:

Incomplete question:

Refer to the temperature versus time graph when answering the questions in Parts C through F. A system consists of 250 of water. The system, originally at = 21.0 , is placed in a freezer, where energy is removed from it in the form of heat at a constant rate. The figure shows how the temperature of the system takes to drop to, after which the water freezes. Once the freezing is complete, the temperature of the resulting ice continues to drop, reaching temperature after an hour. The following specific heat and latent heat values for water may be helpful.

specific heat of ice (at ) = 2.10 J/g K

latent heat of fusion (ice to water phase change at ) = 333.7 J/g

specific heat of water (at ) = 4.186 J/g K

latent heat of vaporization (water to steam phase change at ) = 2256 J/g

specific heat of steam (at ) = 2.01 J/g K

Answers:

Qtotal = 237775 J

Explanation:

To solve this exercise it is necessary to know that if the system is a single phase in which there is a temperature change or if it is a phase change at a single temperature. In the first case, the following formula would be used to calculate the amount of heat:

Q₁ = mCpΔT

Here

m is the mass = 250 g

Cp is the specific heat of ice = 2.1 J/g K

ΔT = 21 - 0 = 21°C = 294 K

In this case the amount of energy is

Q₁ = 250*2.1*294 = 154350 J

In the second case, where there is a phase change at a single temperature, the amount of heat is:

Q₂ = mLf

Here

Lf = latent heat of fusion (ice to water phase change) = 333.7 J/g

Substituting:

Q₂ = 250*333.7 = 83425 J

The total heat is:

Qtotal = 154350+83425=237775 J

7 0

3 years ago

PLS HELP BEING TIMED!!!

Elodia [21]

Answer:

$K_{i}+U_{g,i} = K_{f}+U_{g,f}$

Explanation:

A closed system is a system where exists energy interactions with surroundings, but not mass interactions. If we neglect any energy interactions from boundary work, heat, electricity, magnetism and nuclear phenomena and assume that process occurs at steady state and all effects from non-conservative forces can be neglected, then the equation of energy conservation is reduce to this form:

$\Delta K +\Delta U_{g} = 0$ (1)

Where:

$\Delta K$ - Change in kinetic energy of the system, measured in joules.

$\Delta U_{g}$ - Change in gravitational potential energy of the system, measured in joules.

If we know that $\Delta K=K_{i}-K_{f}$ and $\Delta U_{g} = U_{g,i}-U_{g,f}$ , then we get the following equation:

$K_{i}+U_{g,i} = K_{f}+U_{g,f}$ (2)

Where $i$ and $f$ stands for initial and final states of each energy component.

Hence, the right answer is $K_{i}+U_{g,i} = K_{f}+U_{g,f}$

7 0

3 years ago

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The solar nebula was a

tangare [24]

Solar Nebula

Our solar system began forming within a concentration of interstellar dust and hydrogen gas called a molecular cloud. The cloud contracted under its own gravity and our proto-Sun formed in the hot dense center. The remainder of the cloud formed a swirling disk called of the solar nebula.

4 0

4 years ago

Average speed can be represented by the mathematical expression

nevsk [136]

Average speed is defined as total distance moved in total interval of time

so it is given as

$v_{avg} = \frac{distance}{time}$

now here is we show distance by "d" and time by"t"

then we will have mathematical expression as follows

$v = \frac{d}{t}$

5 0

3 years ago

ANSWER ASAP Which factor determines the amount of gas that can dissolve in ocean water? (A) the motion of the air above the ocea

Andru [333]

Answer:

The amount of each gas that can dissolve in the ocean depends on the solubility and saturation of the gas in water. Solubility refers to the amount of a dissolved gas that the water can hold under a particular set of conditions, which are usually defined as 0o C and 1 atmosphere of pressure.

Explanation:

hope this helps

6 0

3 years ago

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