Two identical melts of are cooled from 2000 °C to room temperature under different…
CHEMISTRY · Single correct · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
Two identical melts of SiO2 are cooled from 2000 °C to room temperature under different conditions. Sample 1 is cooled slowly in a furnace at 1 °C min−1, whereas Sample 2 is quenched by pouring the melt onto a cold metallic plate. Which statement most accurately compares the structures of the two resulting solids?
(a) Sample 2 is more crystalline because rapid cooling prevents the formation of an amorphous network.
(b) Both samples acquire essentially the same crystalline structure since they have identical chemical composition.
(c) Sample 1 is more crystalline because slow cooling gives atoms time to arrange into an ordered lattice.
(d) Sample 2 will possess larger crystals than Sample 1 because fast cooling promotes quick crystal growth.