The metal lithium crystallizes in a body centered cubic unit cell with one atom per lattice point. when x-rays with λ = 0.7873 å are used, the second-order bragg reflection from a set of parallel planes in a(n) lithium crystal is observed at an angle θ = 12.96°. if the spacing between these planes corresponds to the unit cell length (d = a), calculate the radius of a(n) lithium atom.

Silver tarnishes as silver metal reacts with hydrogen sulfide, h2s, in the air. in this reaction, dark silver sulfide, au2s, covers the surface of silver. when silver is polished, this coating of silver sulfide can be removed from the surface. this makes the silver shiny again. enter the coefficients that balance the tarnishing reaction equation. (type 1 for no coefficient.)

Two metal blocks that have slightly different temperatures are placed next to one another. after five minutes, they both have lower but equal temperatures. according to the law of conservation of energy, what  most likelyhappened? energy was created inside the blocks.energy was destroyed inside the blocks.energy was absorbed into the blocks from outside the system.energy was transferred from the warmer block to the cooler block.

Which is an example of a reversible physical change?