If you need 2.5 moles of Rb2Cr7, how many grams do you need?

he heat of fusion of tetrahydrofuran is . Calculate the change in entropy when of tetrahydrofuran melts at . Be sure your answer

lana [24]

Answer:

$\Delta S=1.8x10^{-3}\frac{kJ}{K}=1.8\frac{J}{K}$

Explanation:

Hello.

In this case, given the heat of fusion of THF to be 8.5 kJ/mol and freezing at -108.5 °C, for the required mass of 5.9 g, we can compute the entropy as:

$\Delta S=\frac{n*\Delta H}{T}$

Whereas n accounts for the moles which are computed below:

$n=5.9g*\frac{1mol}{72g} =0.082mol$

Thus, the entropy turns out:

$\Delta S=\frac{0.0819mol*8.5 kJ/mol}{(-108.5+273.15)K}\\\\\Delta S=1.8x10^{-3}\frac{kJ}{K}=1.8\frac{J}{K}$

Best regards.

3 0

3 years ago

What is the name of an immune system response to a substance in food?

poizon [28]

Answer:

The adaptive (also called humoral or specific) immune system is typically only involved in immune responses to bacteria, bacterial toxins and virus antigens. It involves the production of antibodies (also called immunoglobulins) against a specific target. The target of an antibody is called an antigen.

3 0

3 years ago

When a mixture of sulfur and metallic silver is heated, silver sulfide is produced. What mass of silver sulfide is produced from

IgorLugansk [536]

The question is incomplete, here is the complete question.

When a mixture of sulfur and metallic silver is heated, silver sulfide is produced. What mass of silver sulfide is produced from a mixture of 3.0g Ag and 3.0g $S_8$ .

Answer : The mass of silver sulfide is produced from a mixture is 3.44 grams.

Explanation : Given,

Mass of Ag = 3.0 g

Mass of $S_8$ = 3.0 g

Molar mass of Ag = 107.8 g/mole

Molar mass of $S_8$ = 256 g/mole

Molar mass of $Ag_2S$ = 247.8 g/mole

First we have to calculate the moles of Ag and $S_8$ .

$\text{ Moles of }Ag=\frac{\text{ Mass of }Ag}{\text{ Molar mass of }Ag}=\frac{3.0}{107.8g/mole}=0.0278moles$

$\text{ Moles of }S_8=\frac{\text{ Mass of }S_8}{\text{ Molar mass of }S_8}=\frac{3.0g}{256g/mole}=0.0117moles$

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction is,

$16Ag(s)+S_8(s)\rightarrow 8Ag_2S(s)$

From the balanced reaction we conclude that

As, 16 mole of $Ag$ react with 1 mole of $S_8$

So, 0.0278 moles of $Ag$ react with $\frac{0.0278}{16}=0.00174$ moles of $S_8$

From this we conclude that, $S_8$ is an excess reagent because the given moles are greater than the required moles and $Ag$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $Ag_2S$

From the reaction, we conclude that

As, 16 mole of $Ag$ react to give 8 mole of $Ag_2S$

So, 0.0278 moles of $Ag$ react to give $\frac{0.0278}{16}\times 8=0.0139$ moles of $Ag_2S$

Now we have to calculate the mass of $Ag_2S$

$\text{ Mass of }Ag_2S=\text{ Moles of }Ag_2S\times \text{ Molar mass of }Ag_2S$

$\text{ Mass of }Ag_2S=(0.0139moles)\times (247.8g/mole)=3.44g$

Therefore, the mass of silver sulfide is produced from a mixture is 3.44 grams.

4 0

4 years ago

Why do animals need carbohydrates in their diets

Sever21 [200]

Answer:

Carbohydrates are energy-providing feed components composed of carbon, hydrogen, and oxygen. They should make up about 75 percent of an animal's diet. The energy they provide powers muscular movements. Carbohydrates also produce the body heat that helps keep the animal warm.

8 0

3 years ago

Find the mass of 1 mole of CuS

andrezito [222]

95.611 g/mol that's the answers

4 0

3 years ago