Calculate the temperature at which the following reaction becomes feasible: 4HCl + O2 -> 2Cl2 + 2H2O Enthalpy: +280 kJ/mol Entropy: +235 J/Kmol A. 1191.49 K B. 65.80 K C. 45.0 K D. 515.0 K

The alkali metals (group 1) consist of lithium (3), sodium (11), potassium (19), rubidium (37), cesium (55), and francium (87). they are soft, metallic solids with low densities and low melting points. based on the data shown in figure 1, how many valence electrons do alkali metals share?

The image compares the arrangement of electrons in two different neutral atoms. a figure labeled atom q has a shaded sphere at the center of three concentric circles. the innermost circle has two black spheres. the middle circle has six black spheres. to the left of this figure is another figure labeled atom p. atom p has a shaded sphere at the center of three concentric circles. the innermost circle has two black spheres. the middle circle has seven black spheres. which of the following best explains the position of the two atoms in the periodic table?

How is it possible for someone to put an ear to a wall and hear someone in the next room?     a. sound waves can travel though solids.    b. the waves travel from room to room via air.    c. there must be some air in the wall so the sound can travel through it.    d. sound waves change to electromagnetic waves and then back again.