Question

When 1 mol of a gas burns at constant pressure, it produces 2422 J

of heat and does 6 kJ of work.

Identify ΔE for the process.
Express your answer using one significant figure.

Identify ΔH for the process.
Express your answer using four significant figures.

Identify q for the process.
Express your answer using four significant figures.

Identify w for the process.
Express your answer using one significant figure.

Answer 1

Answer: First, let's define the terms used in thermodynamics:

ΔE: Change in internal energy of the system.

ΔH: Change in enthalpy of the system.

q: Heat added to or removed from the system.

w: Work done by or on the system.

For a process at constant pressure (such as burning at constant pressure), we have the following relationships:

ΔH = q (Enthalpy change is equal to the heat added or removed at constant pressure)

ΔE = q - w (Change in internal energy is equal to the heat added or removed minus the work done)

Given:

q = 2422 J (heat added to the system, positive because heat is added)

w = 6 kJ = 6000 J (work done by the system on the surroundings, positive because work is done on the surroundings)

Now, let's calculate the values:

ΔE = q - w = 2422 J - 6000 J ≈ -3580 J ≈ -4 × 10^3 J (to one significant figure)

ΔH = q = 2422 J (to four significant figures)

q = 2422 J (to four significant figures)

w = 6000 J (to one significant figure)

So, the answers are:

• ΔE ≈ -4 × 10^3 J (one significant figure)
• ΔH = 2422 J (four significant figures)
• q = 2422 J (four significant figures)
• w = 6000 J (one significant figure)