Thermochemistry- Calorimetry
_______ is a technique used to measure the amount of heat transferred to or from a substance.
Calorimetry
The specific heat of air is 1.007Jg×oC and the specific heat of nitrogen (N2) is 1.040Jg×oC. What is the specific heat of oxygen (O2)?
less than 1.007/Jg/×oC
An object that is classified as having a "cold" temperature, will have ________ kinetic energy.
lower
In calorimetry, we designate the substance or set of substances undergoing a change as the:
system
What is the substance undergoing a chemical or physical change known as?
system
Which of the following is NOT a chemical change?
tap water is run through a filter
Which of the following would have the highest specific heat?
water
Ideally, the net heat change in a calorimetry experiment will be:
zero
Before landing, the brakes and the tires of an airliner have a temperature of 15.0∘C. Upon landing, the 90.7 kg carbon fiber brakes of an airliner heat up to 312∘C. As the brakes start to cool down, the heat is absorbed by the 123 kg rubber tires. What is the specific heat of the tires if the final temperature of both the brakes and the tires at thermal equilibrium is 172∘C? Enter the answer with three significant figures. Use 1.400Jg∘C for the specific heat of carbon fiber.
0.92 J/g degrees C
If a 20.0 g object at a temperature of 35.0∘C has a specific heat of 2.89Jg∘C, and it releases 450. J into the atmosphere, what will be the final temperature of the object? Report your answer with the correct number of significant figures.
27.2 degree C
A 73.0 g piece of metal with specific heat 0.622 Jg∘C and at 105∘C is placed in 300. g of water at 27.0∘C. What will be the final temperature of the water? Round your answer to one decimal place. Use 4.184Jg∘C for the specific heat of water.
29.7 degrees C
1.45 g of C6H6 is burned in a bomb calorimeter with a heat capacity of 850. J∘C and 785 g of water, the temperature changes from 30.0∘C to 44.2∘C. How much heat, in kilojoules, is released by the reaction? The specific heat capacity of water is 4.184 Jg ∘C. Your answer should have three significant figures.
58.7 kJ
What is a calorimeter?
A device used to measure the quantity of heat transferred to or from an object.
An object that is classified as having a "hot" temperature, will have _______ kinetic energy.
higher
Heat is abbreviated as:
q
The kinetic energy associated with the random motion of atoms and molecules is called:
thermal energy
Any calorimeter must be:
calibrated
A device that measures the heat involved in a physical or chemical process is called a:
calorimeter
What device is used to measure the amount of heat involved in a chemical or physical process?
calorimeter
Simple calorimeters constructed from polystyrene cups are called:
coffee cup calorimeters
When an object's temperature _______, it often expands.
increases
Which is the largest unit of energy?
joule
Which of the following summarizes this observation: "energy can neither be created nor destroyed"?
law of conservation of energy
If the liquid inside a container is 30∘C and the surrounding environment is 25∘C, then:
q will be negative
An exothermic process:
releases energy
If a hot and cold object come into contact, heat is transferred until:
thermal equilibrium is reached
A calorimeter can be used to calculate:
specific heat
Jg/×oC is a unit of which of the following?
specific heat
In a calorimeter, the components of the measuring apparatus that serve to either provide heat or absorb heat are called the:
surroundings
What serves to provide heat or absorb heat from a system?
surroundings
In a calorimeter, the substance(s) undergoing the physical or chemical change is(are) called the:
system
Which of the following is NOT a likely indicator of a chemical change?
the change in shape of a malleable metal
Which of the following objects has more kinetic energy than it does potential energy?
the pendulum of a grandfather clock at the lowest point of its arc of motion
What is work, in a scientific context?
the process of causing matter to move against an opposing force
If a reaction inside a calorimeter is endothermic, we should see
the surrounding temperature go down
A 0.5g sample of C10H8 is burned in a calorimeter that contains 650 g of water at 20.0∘C. The heat capacity of the calorimeter is 420J∘C. If the final temperature of the water is 26.4∘C, what is the heat of combustion of the sample? Use cH2O=4.184 Jg ∘C.
-20 kJ
When 0.963 g of benzene, C6H6, is burned in a bomb calorimeter, the temperature of the calorimeter (and the water it contains) increases by 8.39∘C. The calorimeter has a heat capacity of 784J∘C and is submerged in 925 mL of water. How much heat was produced by the combustion of the benzene sample, in kilojoules? Assume the density of water at this temperature is 1 g/mL. Your answer should have three significant figures. Remember, heat produced corresponds to a −q value.
-39 kJ
A 1.00 g sample of octane (C8H18) is burned in a bomb calorimeter with a heat capacity of 837J∘C that holds 1200. g of water at 25.0∘C. After the reaction, the final temperature of the water is 33.2∘C . Calculate the heat of combustion for 1.00mol of octane. Use 4.184Jg∘C for the specific heat capacity of water. Your answer should have three significant figures.
-5490 kJ
An object with a heat capacity of 3.40×103J∘C absorbs 54.0 kJ of heat, beginning at −25.0∘C. What will be the final temperature of the object? Round your answer to one decimal place. Include a negative sign in your answer if needed.
-9.1 degrees C
A 1.0 kg object absorbs 1,303 J of heat energy and experiences a temperature increase of 5.2∘C. What is the object's specific heat, in joules per gram-degree celsius? Report your answer with the correct number of significant figures.
0.25 J/(g degrees C)
The SI unit for energy is the Joule. Which of the following is/are equal to 1 joule?
1 N x M 1 kg x m^2/s^2
What will be the final temperature of a 207.0 g piece of copper (specific heat = 0.385Jg∘C) that absorbs 5.00 kJ of heat starting at 80.4∘C? Report your answer with the correct number of significant figures.
143.13 degree C
A piece of metal has a heat capacity of 741J∘C and is heated from 20.0∘C to 42.0∘C. How much heat was absorbed to cause this temperature increase? Round the answer to three significant figures.
16,300 J
A 16.0 g copper pan at 200.0∘C is plunged into 200.0 mL of water at 25.0∘C causing the water to rise to 67.0∘C. What is the specific heat of the copper? Use 4.184Jg∘C for the specific heat of water. Water has a density of 1 g mL.
16.52 J/g degrees C
A 21.5 g piece of iron at 100.0∘C is dropped into 132 g of water at 20.0∘C. What is the final temperature of the system, in degrees Celsius, if the specific heat of iron is 0.449Jg∘C? Round your answer to one decimal place. Use 4.184Jg∘C for the specific heat of water
21.4 degrees C
A bomb calorimeter contains 900.0 g of water after a 1.890 g sample of benzoic acid is burned (Heat of Reaction =−3227kJmol). If the temperature of the water increases 8.320∘C, what is the calorimeter constant in J∘C? The molar mass of benzoic acid is 122.12 g/mol. Use 4.184 Jg ∘C for the specific heat capacity of water. Your answer should have four significant figures.
2237 J/ degrees C
The specific heat of water is 4.184Jg ∘C. Determine the final temperature when 600.0 g water at 75.5∘C absorbs 5.90×104 J of energy. Report your answer with three significant figures.
99 degrees C
Which of the following is true?
Heat flow will continue between objects until the substances in question are at the same temperature.
A chef places a cold glass of water into a hot pan. Which of the following is true about the heat flow between these two bodies?
Heat will flow from the pan to the water, making the water warmer and the pan colder until they are both the same temperature.
What is the purpose of the coffee cup calorimeter featured in the image above? (Select all that apply)
The coffee cup calorimeter is an easy way to measure temperature because its insulation limits heat loss. The calorimeter system can be used to measure temperature change for a substance. Using the temperature measured from the calorimeter system is used in further calculations. The calorimeter system helps measure the amount of heat involved in a chemical or physical process.
What is calorimetry?
The process of measuring the amount of heat released or absorbed during a chemical reaction.
A chemist measures the thermometer in the calorimeter and notices the temperature has increased. What does this mean about the reaction that has taken place inside the calorimeter?
The reaction was exothermic, meaning it released heat and increased the temperature of its surroundings.
One cast iron pan has a mass of 2.26kg and a second cast iron pan has a mass of 3.54kg. Which of the following statements are true? (select all that apply)
The two pans will have the same specific heat capacity. The heat capacity of the larger pan will be greater than the heat capacity of the smaller pan.
Which of the following is an example of an exothermic process?
a candle burning
Calibration of a bomb calorimeter is performed with:
a reaction with known q
Most thermometers use what property of metals to measure temperature?
ability to expand with rising temperature
An endothermic process:
absorbs energy
A bomb calorimeter is typically used for:
all of the above
A primary feature of any calorimeter must be:
all of the above
Which object has the most gravitational potential energy?
an airplane in mid-flight
Which unit of energy is defined as the amount of energy required to raise the temperature of one gram of water by 1∘C?
calorie
When an object's temperature _______, it contracts.
decreases
Which of the following is NOT a type of energy?
density energy
Calibration of a bomb calorimeter occurs:
each time the calorimeter is used
A cold pack utilizes what kind of reaction to cool your skin?
endothermic
A(n)________ is a change that absorbs heat.
endothermic process
A(n)________ is a change that releases heat.
exothermic process
Particles in a hot object, when compared to a colder object, have:
greater kinetic energy
What is the transfer of thermal energy between two bodies at different temperatures known as?
heat
Which of the following are types of energy? (select all that apply)
heat chemical potential kinetic
Thermal energy flows spontaneously from:
high temperature to low temperature
A hot shower is associated with _____________ thermal energy, and the heat will flow from a __________ object to a ___________ object.
high; hot, cold
Calorimeters:
measure changes in temperature
Which of the following is an example of an endothermic process?
melting ice cubes
When thermal energy is transferred from the system to its surroundings, heat (q) is:
negative
When thermal energy is transferred from the surroundings to the system, heat (q) is:
positive
Any calorimeter must have some way of measuring:
temperature
We express quantities of thermal energy by using:
temperature
90% of the energy used on the earth each day comes from:
the sun
If a reaction inside a calorimeter is endothermic, we should see:
the surrounding temperature go down
If a reaction inside a calorimeter is exothermic, we should see __________.
the surrounding temperature go up
If a reaction inside a calorimeter is exothermic, we should see:
the surrounding temperature go up
The area of science that studies the heat exchange in a chemical reaction is called:
thermochemistry
In an endothermic reaction, thermal energy is:
transferred from the system to the surroundings
In an exothermic reaction, thermal energy is:
transferred from the system to the surroundings
