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3 years ago

How is freeze dried ice cream made

1 answer:

4 0

Freeze drying (or lyophilization) removes water from the ice cream by lowering the air pressure to a point where ice sublimates from a solid to a gas. The ice cream is placed in a vacuum chamber and frozen until the water crystallizes. The air pressure is lowered, creating a partial vacuum, forcing air out of the chamber; next heat is applied, sublimating the ice; finally a freezing coil traps the vaporized water. This process continues for hours, resulting in a freeze-dried ice cream slice.

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A bomb calorimetric experiment was run to determine the enthalpy of combustion of ethanol. The reaction is The bomb had a heat c

gulaghasi [49]

Answer:

The enthalpy of combustion of ethanol in kJ/mol is -1419.58 kJ/mol.

Explanation:

The heat absorbed by the bomb and water is equal to the product of the heat capacity and the temperature change. Working with this equation, and assuming no heat is lost to the surroundings, we write :

qcal= Ccal × ΔT= 490 J/K × 276.7 K= 135,583 J = 135.58 kJ

Note we expressed the temperature change in K, because the heat capacity is written in K.

Now that we have the heat of combustion, we need to calculate the molar heat.

Because qsystem = qrxn + qcal and qrxn = -qcal, the heat change of the reaction is -135.58 kJ.

This is the heat released by the combustion of 4.40 g of ethanol ; therefore, we can write the conversion factor as 135.58 kJ/ 4.40 g.

The molar mass of ethanol is 46.07 g, so the heat of combustion of 1 mole of ethanol is :

molar heat of combustion= -135.58 kJ/4.40 g x 46.07 g/ 1 mol= -1419.58 kJ/mol

Therefore, the enthalpy of combustion of ethanol in kJ/mol is -1419.58 kJ/mol.

3 0

3 years ago

1.65g of zinc is used to make 8g of zinc iodide. How much iodine is required for this reaction?

creativ13 [48]

Answer:

6.45 g of iodine, I₂

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

Zn + I₂ —> ZnI₂

Next, we shall determine the mass of Zn and I₂ that reacted from the balanced equation. This can be obtained as follow:

Molar mass of Zn = 65 g/mol

Mass of Zn from the balanced equation = 1 × 65 = 65 g

Molar mass of I₂ = 127 × 2 = 254 g/mol

Mass of I₂ from the balanced equation = 1 × 254 = 254 g

SUMMARY:

From the balanced equation above,

65 g of Zn reacted with 254g of I₂.

Finally, we shall determine the mass of f I₂ needed to react with 1.65 g of Zn. This can be obtained as follow:

From the balanced equation above,

65 g of Zn reacted with 254g of I₂.

Therefore, 1.65 g of Zn will react with = (1.65 × 254)/65 = 6.45 g of I₂.

Thus, 6.45 g of iodine, I₂ is needed for the reaction.

4 0

3 years ago

I’ll really appreciate it if you help me out on this one .

Westkost [7]

1.
-Water levels are dangerously high for wildlife and humans.
-Animals seem to be lost, like the cow and the sheep especially.

2.
-There are not many trees near the water, meaning less areas for wildlife to live.
-There is not much wildlife in general.

Inferences
1. The wildlife shown will move relocate and adapt to another area.
2. Industry — emissions are visible in top left— will continue to hurt the environment. CO2 emissions will increase.

Good luck!

5 0

3 years ago

Identify the gas law that applies to the following scenario: If a gas in a closed container is pressurized from 18.0 atm to 14.0

nalin [4]

Answer:

Gay-Lussac's Law

Explanation:

The pressure is directly proportional to the absolute temperature under constant volume. This states the Gay-Lussac's law. The equation is:

P1T2 = P2T1

Where P is pressure and T absolute temperature of 1, initial state and 2, final state of the gas.

That means the right option is:

- Gay-Lussac's Law

6 0

2 years ago

The formula mass of a compound is the A) sum of the atomic masses of its atoms B) sum of the atomic numbers of its atoms C) prod

Digiron [165]

the

answer

hope

this

helped!

7 0

3 years ago