Question

why must the temperature of the lime mud in the lime kiln reach at least 900 degrees Celsius?

Answer #1

A **lime kiln** is used to produce quicklime
through the calcination of calcium carbonate. The chemical equation
for this transformation is given as:

CaCO_{3} + heat → CaO + CO_{2}

This reaction takes place under controlled reaction temperature
at 900 °C (at this temperature the partial pressure of
CO_{2} is 1 atmosphere), but a temperature around 1000 °C
(at which temperature the partial pressure of CO_{2} is 3.8
atmospheres) is usually used to make the reaction proceed quickly.
Excessive temperature is avoided because it produces unreactive,
"dead-burned" lime.

The rate of change of the temperature of an object is proportional to the difference between the temperature of the object and the temperature of the environment (Newton's Law). In addition, heat flows from the warm to the cold.
Water is boiled in a saucepan and then removed from the heating element, so that the initial temperature of the water is 100 degrees Celsius, while the temperature of the room is 20 degrees Celsius and will be assumed to be...

How many J of energy must be removed when 194.0 g of steam, at a
temperature of 153.0 degrees Celsius, is cooled and frozen into
194.0 g of ice at 0 degrees Celsius? Take the specific heat of
steam to be 2.1kJ/(kg*K).

A hot lump of 45.0 g of iron at an initial temperature of 68.2
degrees celsius is placed in 50.0 mL of H2O initially at 25.0
degrees celsius and allowed to reach thermal equillibrium. What is
the final temperature of the iron and water given that the specific
heat of iron is 0.449 J/(G x degrees celsius)? Assume no heat is
lost to surroundings.

To what temperature, in degrees Celsius, must a 20.2 g sample of
hydrogen gas be heated to, at 128 kPa, to occupy a volume of 222
L?

You must use the Temperature bar just like in the homework
problems to indicate where the initial and final temperatures are
located.Failure to do so will result in a 1 point reduction in
grade...even if answer is correct.
200 g of ethyl alcohol is vapor at 108.5 degrees Celsius. How
much heat in units of Kcal must we remove to cause all
of the mass to become frozen at -127 degrees Celsius?
Q = [x] _____________ kcal

Explain why, to maximize entropy, ice must remain at 0 degrees
Celsius until all of it melts?

Program must be in JAVA.
Write a program that converts temperature from Celsius to
Fahrenheit or vice versa, depending on user's input.
The formula for converting temperature in Celsius to Fahrenheit
is,
Fahrenheit = (9/5) * Celsius + 32
The formula for converting temperature in Fahrenheit to Celsius
is,
Celsius = (5/9) * (Fahrenheit – 32)
Results should be rounded to two decimal points, e.g., 92.56

The exhaust temperature of a heat engine is 290 ∘C∘C .
What must be the high temperature if the Carnot efficiency is to
be 23 %% ?
Express your answer using two significant figures.
A heat engine uses a heat source at 500 ∘C∘C and has an ideal
(Carnot) efficiency of 28 %% .
To increase the ideal efficiency to 42 %% , what must be the
temperature of the heat source?
An ideal Carnot engine is operated between a...

At the time of Onnes and Dewar, it was already known that the
lowest temperature they could ever reach was -273 degrees celsius.
So:
- How did they know this since the lowest temperature actually
reached before the liquefaction of hydrogen by Dewar was around
60k?
- How was absolute zero determined by them?

1. A flask containing 800 g. of water is heated. If the
temperature of the water increases from 20 degrees Celsius to 85
degrees Celsius, how much heat (in joules) did the water
absorb?
2. How much heat, in joules, and in calories, must be added to a
75 g. iron block with a specific heat of 0.451 J/g degree Celsius
to increase its temperature from 25 degrees Celsius to its melting
temperature of 1535 degrees Celsius?
3. Consider sound...

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