\begin{array}{|c|c|c|}
\hline 31&BaO&\rm Oxit\ Bazơ&\rm Bari\ Oxit&153\\
\hline 32&H_2CO_3&\rm Axit&\rm Axit\ Sunfurơ&62\\
\hline 33&Na_2CO_3&\rm Muối&\rm Natri\ Sunfit&106\\
\hline 34&CaCl_2&\rm Muối&\rm Canxi\ Clorua&111\\
\hline 35&AgCl&\rm Muối&\rm Bạc\ Clorua&143,5\\
\hline 36&Pb(NO_3)_2&\rm Muối&\rm Chì\ (II)\ Nitrat&331\\
\hline 37&Al_2O_3&\rm Oxit\ Lưỡng\ Tính&\rm Nhôm\ Oxit&102\\
\hline 38&ZnO&\rm Oxit\ Lưỡng\ Tính&\rm Kẽm\ Oxit&81\\
\hline 39&MgSO_4&\rm Muối&\rm Magie\ Sunfat&120\\
\hline 40&mg(OH)_2&\rm Bazơ&\rm Magie\ Hiđroxit&58\\
\hline\end{array}

Giải thích các bước giải:

\begin{array}{|c|c|c|}\hline \text{CTPT}&\text{Hợp chất}&\text{Đọc tên}&\text{Phân tử khối}\\\hline \text{31. BaO}&\text{Oxit}&\text{Bari oxit}&\text{169 đvC}\\\hline \text{32. }H_2CO_3&\text{Axit}&\text{Axit cacbonic}&\text{62 đvC}\\\hline \text{33. }Na_2CO_3&\text{Muối}&\text{Natri cacbonat}&\text{106 đvC}\\\hline \text{34. }CaCl_2&\text{Muối}&\text{Canxi clorua}&\text{111}\\\hline \text{35. AgCl}&\text{Muối}&\text{Bạc Clorua}&\text{143,5}\\\hline \text{36. }Pb(NO_3)_2&\text{Muối}&\text{Chì (II) nitrat}&\text{331 đvC}\\\hline \text{37. }Al_2O_3&\text{Oxit}&\text{Nhôm oxit}&\text{102 đvC}\\\hline \text{38. }ZnO&\text{Oxit}&\text{Kẽm oxit}&\text{81 đvC}\\\hline \text{39. }MgSO_4&\text{Muối}&\text{Magie sùnat}&\text{120 đvC}\\\hline \text{40. }Mg(OH)_2&\text{Bazơ}&\text{Magie hidroxit}&\text{58 đvC}\\\hline\end{array}