The substances sodium (na), oxygen (o2), and sodium oxide (na2o) participate in this chemical reaction: 4na + o2 → 2na2o. which statement best describes the reaction? a. elements rearrange, but no compounds are created or destroyed. b. sodium oxide is created by the chemical reaction. c. atoms from sodium oxide rearrange to form sodium and oxygen. d. in a mixture of the three substances, sodium oxide separates from the sodium and oxygen.

Critical mass is the of material required to produce a chain reaction. a.) minimum amount b.) atomic mass c.) precise amount d.) maximum amount

Estimate the schwarzschild radius (in kilometers) for a mini-black hole formed when a superadvanced civilization decides to punish you (unfairly) by squeezing you until you become so small that you disappear inside your own event horizon. (assume that the your weight is 50 kg)

Beryl states that insulation with the smallest possible thermal conductivity is best to keep a house warm in winter, but worst for keeping a house cool in summer. sapphire insists the reverse is true: low thermal conductivity is good in the summer, but bad in the winter. which one, if either is correct? a. beryl, because low thermal conductivity results in low heat transfer. b. beryl, because low thermal conductivity results in high heat transfer. d. sapphire, because low thermal conductivity results in high heat transfer. e. neither, because low heat transfer is desirable both in summer and in winter.