Energy is conserved: ΔU=Q-W.
Energy is conserved: Q-W=ΔU (closed) or Q̇-Ẇ=Σṁ(h+V²/2+gz)out-Σṁ(...)in (steady flow). It applies to every system and process, and allows unknown heat, work or state to be found from known quantities.
Compressing gas with 50 kJ of work while losing 20 kJ as heat raises internal energy by 30 kJ.
The first law is the energy conservation statement for thermal systems, and every energy calculation depends on it.
Energy is conserved: ΔU=Q-W.
The first law is the energy conservation statement for thermal systems, and every energy calculation depends on it.
The change in internal energy equals the heat added minus the work done by the system, so energy is conserved.
No. It only conserves energy. The second law determines whether a process is possible and in which direction it proceeds.
Typical applications include calculating the heat needed to compress and cool a gas in a compressor, checking the energy balance of a closed piston cylinder during an expansion and verifying the performance of a heat engine from measured heat and work.
Study "Internal energy and enthalpy" first (topic 9 of 105 in Thermodynamics & Fluids). It covers the groundwork this topic builds on.
Include KE and PE if significant. Sign convention. Cannot create or destroy energy.
Compressing gas with 50 kJ of work while losing 20 kJ as heat raises internal energy by 30 kJ.
The next topic is "Ideal gas law", which builds directly on this one.
It is classed as Beginner in Thermodynamics & Fluids (topic 10 of 105). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
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