Which of these must be an organic compound? sodium chloride water carbon dioxide hydrogen peroxid?

One kilogram of water at 100 0C is cooled reversibly to 15 0C. Compute the change in entropy. Specific heat of water is 4190 J/K

mina [271]

Answer:

The change in entropy is -1083.112 joules per kilogram-Kelvin.

Explanation:

If the water is cooled reversibly with no phase changes, then there is no entropy generation during the entire process. By the Second Law of Thermodynamics, we represent the change of entropy ( $s_{2} - s_{1}$ ), in joules per gram-Kelvin, by the following model:

$s_{2} - s_{1} = \int\limits^{T_{2}}_{T_{1}} {\frac{dQ}{T} }$

$s_{2} - s_{1} = m\cdot c_{w} \cdot \int\limits^{T_{2}}_{T_{1}} {\frac{dT}{T} }$

$s_{2} - s_{1} = m\cdot c_{w} \cdot \ln \frac{T_{2}}{T_{1}}$ (1)

Where:

$m$ - Mass, in kilograms.

$c_{w}$ - Specific heat of water, in joules per kilogram-Kelvin.

$T_{1}$ , $T_{2}$ - Initial and final temperatures of water, in Kelvin.

If we know that $m = 1\,kg$ , $c_{w} = 4190\,\frac{J}{kg\cdot K}$ , $T_{1} = 373.15\,K$ and $T_{2} = 288.15\,K$ , then the change in entropy for the entire process is:

$s_{2} - s_{1} = (1\,kg) \cdot \left(4190\,\frac{J}{kg\cdot K} \right)\cdot \ln \frac{288.15\,K}{373.15\,K}$

$s_{2} - s_{1} = -1083.112\,\frac{J}{kg\cdot K}$

The change in entropy is -1083.112 joules per kilogram-Kelvin.

7 0

3 years ago

What changes occur in the nuclei of atoms involved in the reactions that fuel nuclear power plants?

Marina CMI [18]

Nuclear fusion and nuclear fission are two different types of energy-releasing reactions that occur in the nuclei of an atom.
Here are the major differences between the two:

1. To differentiate the two, fission is the splitting of an atom into two or more smaller atoms while fusion is the conjoining or fusion of two or smaller atoms into larger one.

2. Fission does not normally occur in nature while fusion occurs mostly in heavenly bodies such as the stars.

3.Fission produces highly radioactive particles that can be hazardous to both the living things and its habitat or environment while fusion is "clean energy" and "environmental friendly" meaning there are fewer radioactive particles are produced. But if a fission "trigger" is being used, there will be radioactive particles produced.

Among the two nuclear changes, fission is widely used because this reaction produces heat in nuclear reactor. This heat is used to generate steam which operates the turbines to eventually produce electricity.

8 0

3 years ago

The reaction (CH3)3CBr + OH- (CH3)3COH + Br- in a certain solvent is first order with respect to (CH3)3CBr and zero order with r

son4ous [18]

Answer and Explanation:

The rate constant (K) is related to activation energy (Ea), frequency factor (A) and temperature (T) in Kelvin by the equation

R = molar gas constant

K = A(e^(-Ea/RT))

Taking natural log of both sides

In K = In A - (Ea/RT)

In K = (-Ea/R)(1/T) + In A

Comparing this to the equation of a straight line; y = mx + c

y = In K, slope, m = (-Ea/R), x = (1/T) and intercept, c = In A

a) From the question, m = (-Ea/R) = -1.10 × (10^4) K

(-Ea/R) = -1.10 × (10^4) = -11000

R = 8.314 J/K.mol

Ea = -11000 × 8.314 = 91454 J/mol = 91.454 KJ/mol

b) c = In A = 33.5

A = e^33.5 = (3.54 × (10^14))/s

c) K = A(e^(-Ea/RT))

A = (3.54 × (10^14))/s, Ea = 91454 J/mol, T = 25°C = 298.15 K, R = 8.314 J/K.mol

K = (3.54 × (10^14))(e^(-91454/(8.314×298.15))) = 0.0336/s

QED!

5 0

3 years ago

Oftentimes solubility of a compound limits the concentration of the solution that can be prepared. Use the solubility data given

bulgar [2K]

Answer:

NaNO3 (solubility = 89.0 g/100 g H2O)

Explanation:

The solubility of a specie is the amount of solute that will dissolve in one litre of the solvent. Solubility is usually expressed in units of molarity.

Now let us calculate the molarity of the NaNO3 (solubility = 89.0 g/100 g H2O)

Molar mass of NaNO3= 23+14+3(16)= 85gmol-1

Mass of solute=89.0g

Amount of solute= mass of NaNO3/molar mass of NaNO3

Amount of solute= 89.0g/85.0 gmol-1

= 1.0moles of NaNO3

Note that 100g of water=100cm^3 of water.

If 1.0 moles of NaNO3 dissolve in 100cm^3 or water therefore,

x moles of NaNO3 will dissolve in 1000cm^3 of water

x= 1.0 × 1000/ 100

x= 10.0 moles of NaNO3

3 0

3 years ago

A 0.175 M solution of an enantiomerically pure chiral compound D has an observed rotation of +0.27° in a 1-dm sample

-BARSIC- [3]

Answer:

The specific rotation of D is 11.60° mL/g dm

Explanation:

Given that:

The path length (l) = 1 dm

Observed rotation (∝) = + 0.27°

Molarity = 0.175 M

Molar mass = 133.0 g/mol

Concentration in (g/mL) = 0.175 mol/L × 133.0 g/mol

Concentration in (g/mL) = 23.275 g/L

Since 1 L = 1000 mL

Concentration in (g/mL) = 0.023275 g/mL

The specific rotation [∝] = ∝/(1×c)

= 0.27°/( 1 dm × 0.023275 g/mL )

= 11.60° mL/g dm

Thus, the specific rotation of D is 11.60° mL/g dm

3 0

3 years ago