Calculate the heat needed to convert 10.0 g of solid bromine from -7.2°C to 70.0
ID: 1046433 • Letter: C
Question
Calculate the heat needed to convert 10.0 g of solid bromine from -7.2°C to 70.0°C. Which of the following steps requires the most heat energy: melting the solid bromine, heating the liquid bromine from its melting point to its boiling point, boiling the bromine, or heating the gaseous bromine from its boiling point to 110.0°C.
Melting point for bromine -7.2°C, heat of fusion for bromine = 66.15 J/g; specific heat of liquid bromine = 0.474 J/g°C; boiling point for bromine = 58.7°C, heat of vaporization for bromine = 193.21 J/g, specific heat of gaseous bromine = 0.225 J/g°C.
Explanation / Answer
Q = mc?T
Q = heat energy (Joules, J), m = mass of a substance (kg)
c = specific heat (units J/kg?K), ? is a symbol meaning "the change in"
?T = change in temperature (Kelvins, K)
Q = melting the solid bromine + heating the liquid bromine from its melting point to its boiling point + boiling the bromine + heating the gaseous bromine to 70.0°C
Q = 10 x 66.15 + 10 x 0.474 x (58.7 + 7.2 ) + 10 x 193.21 + 10 x 0.225 x (70 - 58.7)
Q = 661.5 + 312.366 + 1932.1 + 25.425
Q = 2931.391 Joules
2931.391 Joules of heat needed to convert 10.0 g of solid bromine from -7.2°C to 70.0°C
boiling the bromine step will requires the most heat energy (1932.1)
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.