Calculate the amount of heat that must be released to convert 20.0 g of mercury vapor at #387^@"C"# to liquid mercury at #307^@"C"# (in kJ)?

Answer 1
Heat added or removed from a substance when there is a change of temperature without a change in phase (#H#) # = m.s. Deltat#
where #m# is mass of substance #s# is specific heat #Deltat# is absolute change in temperature

However, we need to appreciate the underlying steps in the thermal transformation taking place. The change takes place in 3 steps:

Step I: #H_1 = 20*0.104*(387-357)# Vapour #=> H_1 = 20*0.104*30 = 62.4 J#
Step II: #H_2 = 292*20 = 5840 J# Phase transition
Step III: #H_3 = 20*0.138*(357-307)# Liquid #=> H_3 = 20*0.138*50 = 138 J#
Total heat removed = #H_1+H_2+H_3 = 62.4 + 5840 + 138 J = 6.040 kJ #
Sign up to view the whole answer

By signing up, you agree to our Terms of Service and Privacy Policy

Sign up with email
Answer 2

To calculate the heat released, use the formula: ( q = m \cdot C \cdot \Delta T ), where ( q ) is the heat, ( m ) is the mass, ( C ) is the specific heat, and ( \Delta T ) is the temperature change. For mercury, ( C ) is 0.140 J/g°C. First, find the heat to cool the vapor to 307°C, then the heat to condense it at that temperature.

[ q = (20.0 , \text{g}) \cdot (0.140 , \text{J/g°C}) \cdot (387°C - 307°C) + (20.0 , \text{g}) \cdot (295 , \text{J/g}) ]

[ q = 2800 , \text{J} + 5900 , \text{J} ]

[ q = 8700 , \text{J} = 8.7 , \text{kJ} ]

Sign up to view the whole answer

By signing up, you agree to our Terms of Service and Privacy Policy

Sign up with email
Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

Not the question you need?

Drag image here or click to upload

Or press Ctrl + V to paste
Answer Background
HIX Tutor
Solve ANY homework problem with a smart AI
  • 98% accuracy study help
  • Covers math, physics, chemistry, biology, and more
  • Step-by-step, in-depth guides
  • Readily available 24/7