Live practice

A mixture of 1.57 mol of N2, 1.92 mol of H2 and 8.13 mol of NH3 is introduced into a 20 L reaction vessel at 500 K. At this temperature, the equilibrium constant, Kc for

Using ΔfH° values CO=−110, CO₂=−393, N₂O=81 and N₂O₄=9.7 kJ mol⁻¹, find ΔrH° for N₂O₄+3CO→N₂O+3CO₂.

Two drawings of H₃PO₃ place a hydrogen on different atoms. Are they resonance contributors? Explain.

For N³⁻, O²⁻, F⁻, Na⁺, Mg²⁺ and Al³⁺, state

A metal emits electrons with zero kinetic energy at wavelength 6800 Å. Calculate its threshold frequency and work function.

Methanol has density \(0.793\,\mathrm{kg}\) L⁻¹. What volume of methanol is required to make 2.50 L of a 0.250 M methanol solution?

A 10 kW drill heats an \(8.0\,\mathrm{kg}\) aluminium block for 2.5 min; only 50% of the power heats the block. Find ΔT for c=0.91 J g⁻¹ K⁻¹.

A 100.0 L sample of water changes in volume by 0.5 L when pressure changes by 100 atm. Estimate the magnitude of its bulk modulus; 1 atm=1.013×10⁵ Pa.

Between Earth and Sun, where is their net gravitational force on a rocket zero? Use Mₛ=2×10³⁰ kg, Mₑ=6×10²⁴ kg and separation 1.5×10¹¹ m.

An electron has kinetic energy 10 keV and a proton 100 keV. Which is faster, and what is the speed ratio? Use mₚ/mₑ≈1833.