Many famous “rubies” are in fact spinels, which look like rubies but are far less valuable. Spinels consist primarily of MgAl2O4, whereas rubies are primarily Al2O3. If the Timur Ruby, a 361-carat spinel, were pure MgAl2O4, how many moles of MgAl2O4 would it contain? (There are exactly 5 carats per gram.)

Calculate the enthalpy of the following reaction: 4 b (s) + 3 o2 (g) → 2 b2o3 (s) given the following pertinent information: (a) b2o3 (s) + 3 h2o (g) → 3 o2 (g) + b2h6 (g), δhoa = +2035 kj (b) 2 b (s) + 3 h2 (g) → b2h6 (g), δhob = +36 kj (c) h2 (g) + latex: \frac{1}{2} 1 2 o2 (g) → h2o (l), δhoc = −285 kj (d) h2o (l) → h2o (g), δhod = +44 kj

Is laundry detergent an acid or a base?

Which fact represents evidence for the big bang theory?