calorie (energy) calculations a calorie is defined as the amount of energy it takes to raise the...
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![Page 1: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/1.jpg)
Calorie (energy) Calculations
• A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius.
• So if we want to raise 10 grams of water by 1 degree Celsius, it requires ______ calories.
• And if we want to raise 10 g of water by 10 ˚C, it requires _______ calories.
• How did you do that math?
![Page 2: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/2.jpg)
Calorie (energy) Calculations
• There is an equation to streamline that math.
Q=mcΔTEn
ergy
, in
cal
Mas
s, in
g
Spec
ific
heat
cap
acity
, in
cal
/g˚C
Change in temp, in ˚C
![Page 3: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/3.jpg)
What is c??
• “c” is the specific heat capacity.• That is the amount of energy it takes to change
the temperature of 1 gram of the substance by 1 ˚C.
• Does that sound familiar?• In your yellow data book, find the table with
physical constants for water.• What value (number and units) does “c” have
for liquid water?
![Page 4: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/4.jpg)
Try one out!
• How much energy is absorbed if 12.3 g of water is heated from 15.0 ˚C to 35.0 ˚C?
• First, define your variables: Q = we don’t know, this is what you’re looking for m = mass of water = 12.3 g c = specific heat capacity = 1.000 cal/g ˚C ΔT = change in temp = 35 ˚C - 15 ˚C = 20.0 ˚C
Then plug numbers in to your equation: Q = mcΔT = (12.3g)*(1.000 cal/g ˚C)*(20.0 ˚C) Q = 246 cal
![Page 5: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/5.jpg)
Try one out!
• How much energy is absorbed if 35.6 g of water is heated from 15.0 ˚C to 35.0 ˚C?
• First, define your variables: Q = we don’t know, this is what you’re looking for m = mass of water = c = specific heat capacity = 1.000 cal/g ˚C ΔT = change in temp =
Then plug numbers in to your equation: Q = mcΔT
![Page 6: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/6.jpg)
Q = 712 cal
![Page 7: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/7.jpg)
Try one out (this time a different direction)!
• If 211 cal of heat energy is added to 16.0 grams of water, how much will the temperature increase?
• First, define your variables: Q = 211 cal m = mass of water = 16.0 g c = specific heat capacity = 1.000 cal/g ˚C ΔT = change in temp = what we are looking for
Then plug numbers in to your equation: Q = mcΔT
![Page 8: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/8.jpg)
ΔT = 13.2 °C
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Try one out (this time a different direction)!
• If 315 cal of heat energy is added to 9.10 grams of water that starts at 27.0 ˚C, what will the final temperature be?
• First, define your variables: Q = m = mass of water = c = specific heat capacity = 1.000 cal/g ˚C ΔT = change in temp = what we are looking for
Then plug numbers in to your equation: Q = mcΔT
Once you have calculated the change, how can you find the final temperature??
![Page 10: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/10.jpg)
ΔT = 34.6 °C
Final temperature = 27.0 + 34.6 = 61.6°C
![Page 11: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/11.jpg)
One more (another different direction )!
• If 321 cal of heat energy is added to some water, and the water increases by 2.60 ˚C, what was the mass of the water?
• First, define your variables: Q = m = mass of water = what we are looking for c = specific heat capacity = 1.000 cal/g ˚C ΔT = change in temp = Then plug numbers in to your
equation: Q = mcΔT
![Page 12: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/12.jpg)
m = 123g
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What if you are melting ice?
• Remember from your heating curve, while ice is melting, the temperature stays the same…
• So we need a new equation!
Q = mHf
Ener
gy, i
n ca
l
Mas
s, in
g
Heat of fusion, in cal/g
![Page 14: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/14.jpg)
What is Hf??
• “Hf” is the heat of fusion.• That is the amount of energy it takes to
change 1 gram of the substance from a solid to a liquid (to melt it).
• In your yellow data book, find the table with physical constants for water.
• What value (number and units) does “Hf” have for water?
![Page 15: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/15.jpg)
Try one out!
• How much energy is absorbed if 12.3 g of ice is melted?
• First, define your variables: Q = we don’t know, this is what you’re looking for m = mass of water = 12.3 g Hf = heat of fusion= 79.72 cal/g
Then plug numbers in to your equation: Q = mHf = (12.3g)*(79.72 cal/g) Q = 981 cal
![Page 16: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/16.jpg)
Try one out!
• How much energy is absorbed if 35.6 g of ice is melted?
• First, define your variables: Q = we don’t know, this is what you’re looking for m = mass of water = Hf = heat of fusion= 79.72 cal/g
Then plug numbers in to your equation: Q = mHf = Q =
![Page 17: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/17.jpg)
Q = 2838 cal = 2840 cal with sig figs
![Page 18: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/18.jpg)
Try one out (a different direction this time)!
• If 211 cal of heat energy is added to melt some ice, what mass of ice can be melted?
• First, define your variables: Q = 211 cal m = mass of water = what you are looking for Hf = heat of fusion= 79.72 cal/g
Then plug numbers in to your equation: Q = mHf = Q =
![Page 19: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/19.jpg)
m = 2.65g
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What if you are boiling water?
• Remember from your heating curve, while water is boiling, the temperature stays the same…
• So we need a new equation!
Q = mHv
Ener
gy, i
n ca
l
Mas
s, in
g
Heat of vaporization, in
cal/g
![Page 21: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/21.jpg)
What is Hv??
• “Hv” is the heat of vaporization.• That is the amount of energy it takes to
change 1 gram of the substance from a liquid to a gas (to vaporize it).
• In your yellow data book, find the table with physical constants for water.
• What value (number and units) does “Hv” have for water?
![Page 22: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/22.jpg)
Try one out!
• How much energy is absorbed if 12.3 g of water is vaporized (boiled)?
• First, define your variables: Q = we don’t know, this is what you’re looking for m = mass of water = 12.3 g Hv = heat of vaporization= 539.4 cal/g
Then plug numbers in to your equation: Q = mHv = (12.3g)*(539.4 cal/g) Q = 6634.62 cal = 6630 cal with sig figs
![Page 23: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/23.jpg)
Try one out!
• How much energy is absorbed if 35.6 g of water is vaporized?
• First, define your variables: Q = we don’t know, this is what you’re looking for m = mass of water = Hv = heat of vaporization= 539.4 cal/g
Then plug numbers in to your equation: Q = mHv = Q =
![Page 24: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/24.jpg)
Q = 19202 cal = 19200 cal with sig figs
![Page 25: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/25.jpg)
Try one out (a different direction this time)!
• If 211 cal of heat energy is added to vaporize some water, what mass of water can be vaporized?
• First, define your variables: Q = 211 cal m = mass of water = what you are looking for Hv = heat of vaporization=
Then plug numbers in to your equation: Q = mHv = Q =
![Page 26: Calorie (energy) Calculations A calorie is defined as the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius](https://reader030.vdocuments.mx/reader030/viewer/2022032722/56649f4f5503460f94c706c7/html5/thumbnails/26.jpg)
m = 0.391g