What is the correct elemental symbol and charge for an ion that has 12 protons and 10 electrons?

What is the mass of 0.0911 moles of potassium dichromate (note: dichromate is Cr₂O₇²⁻)?

At point 4 of the graph below, which depicts the energy change associated with the formation of an H–H bond,

When a 0.1 M solution of AgClO₄ and a 0.1 M solution of NaBr are mixed,

If the reaction is at equilibrium and Cl- is increased by adding the strong acid HCl, the equilibrium shifts toward the:

What volume (in mL) of a 0.015 M KOH solution contains the same number of moles of OH- ions as the number of moles of Na+ ions in 300 mL of 0.0025 M NaCl?

For the combustion of glucose (C6H12O6), which choice gives the correct balanced equation AND the correct sign of ∆S (with reason)? 

The value of ∆S is positive for which of the following reactions? 

Nitrous oxide (N2O) is described as very soluble in (nonpolar) cream but only slightly soluble in water. Based on this “like dissolves like” evidence, N2O is best described as:

Calculate the density (in g/L) of xenon gas in a 1200 mL flask at 28 °C and 620 torr. (Xe is monatomic; molar mass 131.3 g/mol.)