You have 750 grams of water at 80° Celsius. Which of the following would lower the temperature of the water by 10° Celsius?
adding 750 grams of water at 50° Celsius
adding 325 grams of water at 60° Celsius
adding 750 grams of water at 60° Celsius
adding 1000 grams of water at 55° Celsius
If you drop a 10 gram piece of metal with a temperature of 100° Celsius into 100 grams of water at 20° Celsius, what best describes what would occur?
The temperature lost by the metal will equal the temperature gained by the water.
The heat lost by the metal will equal the heat gained by the water.
The final temperature of the water will be 60° Celsius.
The final temperature of the water will be more than 60° Celsius.
Which of the following phase changes involves a decrease in entropy?
vaporization of liquid mercury
solid metal melting to form a liquid
condensation of water vapor to form dew
sublimation of dry ice into carbon dioxide gas
PLEASEE HELP ME! :D
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Verified answer
You have 750 grams of water at 80° Celsius. Which of the following would lower the temperature of the water by 10° Celsius?
q=mass(specific heat)(Tf-Ti)
heat lost by original water=heat gained by added water
So -q=q
You know -q=750g(4.18 J/gC)(70-80)=31350 J
You want to find an equivalent heat from the options below. So test the equation for all of them.
adding 750 grams of water at 50° Celsius: 750(4.18)(70-50)=62700 J
adding 325 grams of water at 60° Celsius: 13585 J
adding 750 grams of water at 60° Celsius: 31350 J
adding 1000 grams of water at 55° Celsius: 62700 J
So obviously, option 3 is correct. You could probably even eye it out.
Problem two: same principle as prob 1
Problem three: not sure about this, but with multiple choice like this, it's just pick the odd one out.
use enthalpy.
-Q=Q
Q=(mass in kg)(spcific heat capasity)(difference in temp)
specific heat capasity of liquid water is 4.19J/g