3Ca(s) + 2H3PO4(aq) --> Ca3(PO4)2(s) +3H2(g) How many moles of calcium are required to produce 18.0 g of H2?

Why do sodium and neon have vastly different chemical and physical properties despite having similar atomic masses?

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?

Which type of substance ionizes partially and gives off hydrogen ions when dissolved in water? a. strong acid b. strong base c. weak acid d. weak base