Question

取24 g氢氧化钠和碳酸钠的固体混合物，加136 g水完全溶解后，再缓慢加入石灰乳（氢氧化钙和水的混合物）至恰好完全反应，过滤得到4 g沉淀和10%的氢氧化钠溶液。试计算反应中应加入石灰乳的质量是多少？

Answer 1

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                【解】设：24g样品中碳酸钠的质量为x，生成的氢氧化钠的质量为y

     Ca(OH)₂ + Na₂CO₃===CaCO₃¯ + 2NaOH

               106       100      80

                        4g       y

                

 

= 4.24 g    y = 3.2 g                 .               ..............1分

     得到的10%NaOH溶液的质量为(24 g - 4.24 g + 3.2 g) ¸ 10% = 229.6 g    ..............1分

     加入石灰乳的质量为 229.6 g + 4 g - 136 g -24 g = 73.6 g                ..............1分

答：略