________ is observation through research and the scientific investigation.

Refrigerant-134a enters the coils of the evaporator of a refrigeration system as a saturated liquid-vapor mixture at a pressure

Firdavs [7]

Answer:

(a) 0.699 kJ/K

(b) -0.671 kJ/K

(c) 0.028 kJ/K

Explanation:

The Refrigerant-134a flows into the evaporator as a saturated liquid-vapor mixture and flows out as a saturated vapor at a saturation pressure of 160 kPa and temperature of -15.64°C (estimated from the Saturated Refrigerant-134a Temperature Table).

(a) The entropy change of the refrigerant (ΔS $_{R-134a}$ ) = Q/T $_{1}$

Q = 180 kJ

T $_{1}$ = -15.64 + 273.15 = 257.51 K

ΔS $_{R-134a}$ = Q/T $_{1}$ = 180/257.51 = 0.699 kJ/K

(b) The entropy change (ΔS $_{c}$ ) of the cooled space (ΔS $_{c}$ ) = -Q/T $_{2}$

Q = -180 kJ

T $_{2}$ = -5 + 273.15 = 268.15 K

ΔS $_{c}$ = Q/T $_{2}$ = -180/268.15 = -0.671 kJ/K

(c) The total entropy change for this process (ΔS $_{t}$ ) = ΔS $_{R-134a}$ + ΔS $_{c}$ = 0.699 - 0.671 = 0.028 kJ/K

6 0

4 years ago

Soluble ionic compounds that dissociate naerly completely when dissolved are classified as _______.

Anettt [7]

The answer is D. Strong electrolytes

Strong electrolyte is a solute or solution that completely or almost completely dissociates when in solution. These are good conductors of electricity only when in molten/aqueous solution.

Strong electrolyte(aq) → Cation+(aq) + Anion−(aq)

6 0

3 years ago

Cual es la masa atómica de hidrógeno ?

vekshin1

in Spanish: Cual es la masa atómica de hidrógeno ? 1.00794 u

in English: What is the atomic mass of hydrogen?: 1.00794 u

4 0

3 years ago

Aqueous sulfuric acid reacts with solid sodium hydroxide to produce aqueous sodium sulfate and liquid water . If of water is pro

Lubov Fominskaja [6]

This is an incomplete question, here is a complete question.

Aqueous sulfuric acid (H₂SO₄) reacts with solid sodium hydroxide (NaOH) to produce aqueous sodium sulfate (Na₂SO₄) and liquid water (H₂O) . If 12.5 g of water is produced from the reaction of 72.6 g of sulfuric acid and 77.0 g of sodium hydroxide, calculate the percent yield of water. Round your answer in significant figures.

Answer: The percent yield of water is, 46.8 %

Explanation : Given,

Mass of $H_2SO_4$ = 72.6 g

Mass of $NaOH$ = 77.0 g

Molar mass of $H_2SO_4$ = 98 g/mol

Molar mass of $NaOH$ = 40 g/mol

First we have to calculate the moles of $H_2SO_4$ and $NaOH$ .

$\text{Moles of }H_2SO_4=\frac{\text{Given mass }H_2SO_4}{\text{Molar mass }H_2SO_4}$

$\text{Moles of }H_2SO_4=\frac{72.6g}{98g/mol}=0.741mol$

and,

$\text{Moles of }NaOH=\frac{\text{Given mass }NaOH}{\text{Molar mass }NaOH}$

$\text{Moles of }NaOH=\frac{77.0g}{40g/mol}=1.925mol$

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation is:

$H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O$

From the balanced reaction we conclude that

As, 1 mole of $H_2SO_4$ react with 2 mole of $NaOH$

So, 0.741 moles of $H_2SO_4$ react with $0.741\times 2=1.482$ moles of $NaOH$

From this we conclude that, $NaOH$ is an excess reagent because the given moles are greater than the required moles and $H_2SO_4$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $H_2O$