Question

Dr. Ewing acknowledges that he does not have a problem with
coffee, he has a problem without it. Knowing this, he has asked you
to design a coffee pot that will heat water in as short a time as
possible. If you need to heat 500 mL of water from room temperature
(70^{0}F) to brewing temperature (195^{0}F) in 20
seconds, how much **power**, **in units of
Watts**, is required? You may assume the specific heat of
water is 4.18 J/(g ^{0}C).

Answer #1

a- You have 200 g of coffee at 45 0C, Coffee has the same
specific heat as water. How much ice at -10 0C do you need to add
in order to reduce the coffee’s temperature to 30 0
b- A laboratory technician drops a 0.06 kg sample of unknown
solid material, at a temperature of 100 0C, into a calorimeter. The
calorimeter can, initially at 19 0C, is made of 0.2 kg of copper
and contains 0.15 kg of...

You have 200 g of coffee at 45 0C, Coffee has the
same specific heat as water. How much ice at -10 0C do
you need to add in order to reduce the coffee’s temperature to 30
0

(A) A 36.0 g piece of lead at 130.0 C is placed in 100.0 g of
water at 20.0 C. What is the temperature (in C) of the water once
the system reaches equilibrium? The molar heat capacity of lead is
26.7 J/(mol·K). The specific heat capacity of water is 4.18
J/(g·K).
(B) How much energy (in kJ) will it take to heat up 1150 ml of
water in a coffee pot from 24 C to 95 C given that...

19.
(a)
A freezer maintains an interior temperature inside of −16.0°C
and has a coefficient of performance of 3.00. The freezer sits in a
room with a temperature of 15.0°C. The freezer is able to
completely convert 28.0 g of liquid water at 15.0°C to ice at
−16.0°C in one minute. What input power (in watts) does the
freezer require? (The specific heat of liquid water is
4.186 J/(g · °C), the specific heat of ice is 2.090 J/(g ·...

A 0.217-kg coffee mug is made from a material that has a
specific heat capacity of 989 J/kg C° and contains 0.315 kg of
water. The cup and water are at 25.8 °C. To make a cup of coffee, a
small electric heater is immersed in the water and brings it to a
boil in two minutes. Assume that the cup and water always have the
same temperature and determine the minimum power rating of this
heater.

You have 200 g of coffee at 55C, Coffee has the same specific
heat as water. How much ice at -5C do you need to add in order to
reduce the coffee’s temperature to 27C?

Part A
A copper pot of mass 2.5 kg contains 5.2 litres of water (i.e.
5.2 kg) at room temperature (200C). An iron block of
mass 9.4 kg is dropped into the water and when the system comes
into thermal equilibrium, a temperature of 380C is
measured. What is the initial temperature of the iron block? Give
your answer in oC to three significant figures.
Part B
Iron has a specific heat that is larger than that of copper. A...

a) A freezer maintains an interior temperature inside of −12.0°C
and has a coefficient of performance of 3.00. The freezer sits in a
room with a temperature of 25.0°C. The freezer is able to
completely convert 28.0 g of liquid water at 25.0°C to ice at
−12.0°C in one minute. What input power (in watts) does the freezer
require? (The specific heat of liquid water is 4.186 J/(g · °C),
the specific heat of ice is 2.090 J/(g · °C),...

Calorimetry Problem: Show your work neatly and methodically.
Include the sign associated with ΔH.
1. When a 6.55 gram sample of solid sodium hydroxide dissolves
in 115.00 grams of water in a coffee-cup calorimeter, the
temperature rises from 21.6°C to 38.7°C. Calculate ΔH, in kJ/mole
NaOH, for the solution process. NaOH(s) Na1+(aq) + OH1- (aq) The
specific heat of the solution is 4.18 J/g °C. 3.
2, A 2.600 gram sample of phenol, C6H5OH, was burned in a bomb...

Question 1a : A microwave oven generates 725 W (1 W= 1 J/s) of
power. A styrofoam coffee cup has 100.0 grams of water at 22.5
degrees Celsius. If the wavelength of the microwaves is 9.6 cm, how
many seconds does it take to make the water boil? The specific heat
capacity of water is 4.18 J/g °C. Assume the water retains all
heat.
Question 2a : From the previous question, how many photons of
microwave radiation are required to...

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