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A sample of polystyrene, which has a specific heat capacity of , is put into a calorimeter (see sketch at right) that contains of water. The
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A sample of polystyrene, which has a specific heat capacity of , is put into a calorimeter (see sketch at right) that contains of water. The polystyrene sample starts off at and the temperature of the water starts off at . When the temperature of the water stops changing it’s . The pressure remains constant at . Calculate the mass of the polystyrene sample. Be sure your answer is rounded to significant digits.
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Chemistry
4 years
2021-07-13T14:47:35+00:00
2021-07-13T14:47:35+00:00 1 Answers
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Answers ( )
This question is incomplete, the complete question is;
A sample of polystyrene, which has a specific heat capacity of 1.880 J.g⁻¹, is put into a calorimeter (see sketch at right) that contains 300.0 g of water. The polystyrene sample starts off at 94.9 °C and the temperature of the water starts off at 22.0. When the temperature of the water stops changing it’s 27 °C . The pressure remains constant at 1 atm.
Calculate the mass of the polystyrene sample. Be sure your answer is rounded to 2 significant digits.
Answer:
the mass of the polystyrene sample is 57 g
Explanation:
Given the data in the question;
mass of water m
= 300 g
Temperature of water T
= 22 °C
Specific heat capacity of water C
= 4.184 J/g°C
mass of the polystyrene sample m
= ?
T
= 94.9 °C
Specific heat capacity of polystyrene; C
= 1.880 J.g⁻¹.°C⁻¹
T = 27.7 °C
Now, using heat conservation equation
heat lost by polystyrene = heat gained by water
m
× C
× ( T
– T ) = m
× C
× ( T – T
)
We substitute
m
× 1.880 × ( 94.9 – 27.7 ) = 300 × 4.184 × ( 27.7 – 22 )
m
× 1.880 × 67.2 = 300 × 4.184 × 5.7
m
× 126.336 = 7154.64
m
= 7154.64 / 126.336
m
= 56.63 ≈ 57 g { 2 significant figures }
Therefore, the mass of the polystyrene sample is 57 g