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Which condition defines an adiabatic process?
Adiabatic walls permit no heat transfer between the system and surroundings. Temperature can still change when work is done.
q=0 (option C).
Give Lewis-dot symbols for Mg, Na, B, O, N and Br.
The dots equal the number of valence electrons obtained from the group number. Place single dots on separate sides before pairing.
Mg:2, Na:1, B:3, O:6, N:5 and Br:7 valence dots.
Which property formed the main basis of Mendeleev's classification, and did he follow it without exception?
Mendeleev mainly arranged elements by increasing atomic mass while grouping chemically similar elements. He reversed some mass-based orders, such as Co/Ni and Te/I, when chemical properties demanded it.
Atomic mass was the main basis, but chemical similarity was allowed to override strict mass order.
For (i) 1 mol CH₄, find the total electrons(ii) 7 mg ¹⁴C, find the number and mass of neutrons(iii) 34 mg NH₃, find the number and mass of protons, and state whether temperature or pressure affects the result.
Count electrons, neutrons or protons in one particle, calculate the number of particles from moles, and multiply.
Find the mass percentage of sodium, sulfur and oxygen in sodium sulfate, Na₂SO₄.
First calculate the molar mass. The percentage of an element is its mass contribution divided by the molar mass, multiplied by 100.
A stone falls \(300\,\mathrm{m}\) into water. When is the splash heard at the tower top? Use \(g=9.8\,\mathrm{m\,s}\)⁻² and sound speed \(340\,\mathrm{m\,s}\)⁻¹.
Principle and reasoning. Work from the governing physical relation and apply it to every stated part.
Add the fall time and the sound's upward travel time.
Show that one mole of ideal gas occupies about 22.4 L at STP.
Principle and reasoning. Work from the governing physical relation and apply it to every stated part.
Use the ideal-gas equation for n=1 mol, T=273.15 K and P=1.013×10⁵ Pa.
How much heat raises \(0.020\,\mathrm{kg}\) of nitrogen by 45 K at constant pressure? Use molar mass \(0.028\,\mathrm{kg}\) mol⁻¹, R=8.3 J mol⁻¹ K⁻¹ and Cₚ=7R/2.
Principle and reasoning. Work from the governing physical relation and apply it to every stated part.
Find the number of moles and use Q=nCₚΔT.
Absolute scales A and B assign the water triple point as 200 A and 350 B. Relate readings T_A and T_B.
Principle and reasoning. Work from the governing physical relation and apply it to every stated part.
Absolute scales share zero and differ only by unit size.
Choose how g changes with altitude and depth, what mass it is independent of, and which potential-energy expression is more accurate over a large radial change.
Outside Earth, g=GM/r²; inside a uniform Earth, g falls linearly with depth. Test-body mass cancels from acceleration.