25,6g kim loại X (hóa trị II) tác dụng hoàn toàn với HNO3 đặc nóng cho 17,92 lít khí NO2 (đkc). Kim loại X là

Enough of a monoprotic weak acid is dissolved in water to produce a 0.0172 m solution. if the ph of the resulting solution is 2.39 at 20 °c, determine the pka for the acid.

Which statement best describes the he properties of iconic compounds ?

Asample of tin (ii) chloride has a mass of 0.49 g. after heating, it has a mass of 0.41 g.  what is the percent by mass of water in the hydrate?   %