Specific heat Concepts
What did each variable represent in q=mc(Tf-Ti)?
q=energy
m=mass
c= specific heat
Tf = final temp
Ti = initial temp
How much heat energy (in Joules) is required to raise the temperature of a 50.0 gram sample of water from 20.0∘C to 35.0∘C?
(water specific heat is 4.184 J/g C
3135 J
in -m1c1(Tf-Ti)1 = m2c2(Tf-Ti)1, why is one side negative and one side positive?
One substance is releasing energy, one side is absorbing energy
Imagine you have 10 grams of iron (c=0.45 J/g⋅°C) and 10 grams of glass (c=0.84 J/g⋅°C). If you put both substances under the same heat lamp for five minutes, which material will have a higher final temperature, and why?
Iron. It takes less energy to raise the temp. 1°C
True or false
A substance with high specific heat will be resistant to temperature change when energy is added
True
A 25.0-gram piece of an unknown metal absorbs 1,000 Joules of heat, causing its temperature to rise from 25.0∘C to 125.0∘C. What is the specific heat of the metal in J/g∘C?
0.400 J/g∘C
What was the point of using a coffee cup instead of a normal beaker to record temperature?
to make sure the heat/energy does not escape
The specific heat of water is much higher than that of sand or soil. Use this concept to explain why coastal cities (like San Francisco or Hawaii) have much milder temperature swings between day and night and summer and winter, compared to inland areas (like the desert).
The high specific heat means it won't absorb heat as much, nor will it release heat as readily.
Substance X and Y are different materials. Both have the same mass. The same amount of energy is put into them.
Substance X has a final temp of 30C. Substance Y has a final temp of 60C. Which one has the lower specific heat and why?
Substance Y. It took the same amount of energy and the final temperature was higher.
A 15.0-gram sample of gold (c=0.129 J/g∘C) at an initial temperature of 95.0∘C loses 40.0 Joules of heat to the surroundings. What is the final temperature of the gold?
74.3∘C
A 240-gram chunk of carbon (ccarbon=0.72 J/g∘C) is heated to 215∘C and quickly placed into 275 grams of water at 12∘C. Assuming a perfectly insulated system, what will the final temperature (Tf) of the mixture be?
38.5∘C
When firefighters are trying to cool down a large structure fire, why is water or foam the preferred medium over other common cooling liquids (like vegetable oil or ethanol, which have lower specific heat values)?
Water has a high specific heat and would not heat up as fast
Oil and Ethanol have lower specific heats and would absorb energy quicker. (they are also highly flammable)
When two objects mix together, will their temperatures be similar or different? Why?
Similar because you have created a mixture. That mixture will go through thermal equilibrium and have the same temperature throghout
3000 g gold bar (c=0.129 J/g∘C) at 99 C is dropped into water and had a final temp of 47C. What is the energy that is absorbed by the water?
What is 20124J?
A 590 g brass sample at 98.0 C is dropped into 2800 g of water at 5.0 C. If the temperature of the mixture is 6.8 C, what is the specific heat of brass?
What is 0.392 J/g C?
You place 100 g of copper at 80°C into a fixed amount of water. You then repeat the experiment with 200 g of copper at 80°C in the same amount of water. Which experiment (the 100 g or 200 g copper) results in a higher final equilibrium temperature, and why?
200g. More mass at the same temp means more energy will be transferred to the water.
Which material would you use to heat up your food on a stove and why?
Aluminum 0.900 J/g C
Brass 0.380 J/g C
Copper 0.387 J/g C
Steel 0.120 J/g C
Steel. Lowest Specific heat. It can absorb and transfer energy fast.
A 2000. gram piece of lead is heated from 80.00 to 100.00 Celcius using 5120 J of energy. The specific heat capacity of lead is _______________
What is 0.128 J/g C?
A 75.0-gram piece of metal is heated to 100.0∘C and then placed into a cup containing 50.0 g of water at 22.0∘C. If the final temperature of the metal and water mixture is 28.8∘C, what is the specific heat of the unknown metal?
0.266 J/g∘C
A typical cooking pot has a thin metal body (low c) and a thick ceramic or plastic handle (high c and low conductivity). Explain why the body of the pot and the handle require materials with different thermal properties to function effectively.
Low Specific means better heat absorption and transmittance for cooking. A high specific heat handle is so you can grab the pot