What was the 'elixir of life'

______ reactions generate thermal energy in a nuclear power plant as water is changed into steam

Jet001 [13]

Fission reactions generate thermal energy

8 0

3 years ago

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For a reaction in a galvanic cell both ΔH° and ΔS° are positive. Which of the following statements is true?

irina [24]

Answer:

Option C is the correct statement.

ℰ°cell will increase with an increase in temperature

Explanation:

To understand this problem it is neccessarry to state the relatioonships between the various paramenters mentioned in the question. these parameters include ΔH°, ΔS°, ΔG° and ℰ°Cell.

ΔH°, ΔS°, ΔG° are related with the following equation;

ΔG° = ΔH° - TΔS°

From the above equation we see that ΔG° cannot be greater than 0 for all temperatures. At higher temperatures, ΔG° becomes a negative value.

A spontaneous redox reaction is characterized by a negative value of ΔG and a positive value of ℰ°Cell, consistent with our earlier discussions. When both reactants and products are in their standard states, the relationship between ΔG° and ℰ°Cell is as follows:

ΔG∘=−nFℰ°Cell where;

F = Faraday and n = number of moles

Since ΔG° becomes negative at higher temperatures, it means ℰ°Cell would increase as temperature increases.

The relationship between G, Ecell and temperature can be given as;

Increase in Temperature = Negative value of G = Increase in E

Due to the fact established above; options B, D and E are false. This means the correct option is option C - ℰ°cell will increase with an increase in temperature

3 0

3 years ago

A sample of quartz, which has a specific heat capacity of , is dropped into an insulated container containing of water at and a

klasskru [66]

This question is incomplete, the complete question is;

A 17.0 g sample of quartz, which has a specific heat capacity of 0.730 J.g⁻¹°C⁻¹, is dropped into an insulated container containing 200.0 g of water at 85°C and a constant pressure of 1 atm . The initial temperature of the quartz is 7.2°C.

Assuming no heat is absorbed from or by the container, or the surroundings, calculate the equilibrium temperature of the water. Be sure your answer has the correct 3 number of significant digits.

Answer:

the equilibrium temperature of the water is 83.9°C

Explanation:

Given the data in the question;

Since no heat is absorbed from or by the container, or the surroundings;

Then Heat lost by the quartz = heat gained by water

ΔH1 = ΔH2

DH = mcΔT

where m is mass, C is specific heat capacity and ΔT is temperature change;

so

(mcΔT)1 = (mcΔT)2

we know that; specific heat capacity of is 4200 Joule/Kilogram K (J/kg∙K) = 4.2 (J/g∙°C)

we substitute

17.0g × 0.730 J.g⁻¹°C⁻¹ × ( 7.2°C - T2) = 200.0g × 4.2 J/g∙°C × ( T2 - 85°C)

89.352 - 12.41T2 = 840T2 - 71400

840T2 + 12.41T2 = 89.352 + 71400

852.41T2 = 71489.35

T2 = 71489.35 / 852.41 = 83.86°C ≈ 83.9°C

Therefore, the equilibrium temperature of the water is 83.9°C

3 0

3 years ago

PLZ HELP "NO LINKS"

Natalka [10]

Answer: (a) Mole fraction of $H_{2}$ is 0.66.

Mole fraction of $N_{2}$ is 0.33

(b) The partial pressure of $H_{2}$ is 1.98 atm.

The partial pressure of $N_{2}$ is 0.99 atm.

(c) The total pressure is 3.0 atm

Explanation:

Given: Volume = $22.4 dm^{3}$ (1 $dm^{3}$ = 1 L) = 22.4 L

Moles of $H_{2}$ = 2.0 mol

Moles of $N_{2}$ = 1.0 mol

Total moles = (2.0 + 1.0) mol = 3.0 mol

Temperature = 273.15 K

Now, using ideal gas equation the total pressure is calculated as follows.

$PV = nRT\\$

where,

P = pressure

V = volume

n = number of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.

$PV = nRT\\P \times 22.4 L = 3.0 mol \times 0.0821 L atm/mol K \times 273.15 K\\P = 3.0 atm$

The mole fractions of each component:

The mole fraction of $H_{2}$ is calculated as follows.

$Mole fraction = \frac{moles of H_{2}}{moles of H_{2} + moles of N_{2}}\\= \frac{2.0 mol}{(2.0 + 1.0) mol}\\= 0.66$

The mole fraction of $N_{2}$ is as follows.

$Mole fraction = \frac{moles of N_{2}}{moles of H_{2} + moles of N_{2}}\\= \frac{1.0 mol}{(2.0 + 1.0) mol}\\= 0.33$

The partial pressures of each component:

Partial pressure of $H_{2}$ are as follows.

$P_{H_{2}} = P_{total} \times mole fraction of H_{2}\\= 3.0 atm \times 0.66\\= 1.98 atm$

Partial pressure of $N_{2}$ are as follows.

$P_{N_{2}} = P_{total} \times mola fraction of N_{2}\\= 3.0 atm \times 0.33\\= 0.99 atm$

7 0

3 years ago

S

svetlana [45]

Answer: $1.6\times 10^4$

Explanation:

Scientific notation is defined as the representation of expressing the numbers that are too big or too small and are represented in the decimal form with one digit before the decimal point times 10 raise to the power.

For example : 5000 is written as $5.0\times 10^3$

In division , the result would contain the same number of significant digits as there in the least precise number , thus the answer would have 2 significant digits.

$\frac{1.248\times 10^{-2}}{7.8\times 10^{-7}}=1.6\times 10^4$

5 0

4 years ago

What was the 'elixir of life' ​

What was the 'elixir of life'