Question

某品牌純堿中含有雜質(zhì)NaCl，化學(xué)興趣小組的同學(xué)進(jìn)行了如下實(shí)驗(yàn)探究：稱取12g樣品放入燒杯中，加入稀鹽酸至不再產(chǎn)生氣泡為止，并繪制出加入稀鹽酸的質(zhì)量與放出氣體質(zhì)量的關(guān)系如圖，發(fā)生反應(yīng)：           

Na₂CO₃+2HCl=2NaCl+CO₂↑+H₂O                                      

（1）生成CO₂的質(zhì)量為　　g．                                    

（2）計(jì)算該樣品中含碳酸鈉的質(zhì)量分?jǐn)?shù)是多少？（計(jì)算結(jié)果保留一位小數(shù)）        

                                     

Answer 1

【考點(diǎn)】根據(jù)化學(xué)反應(yīng)方程式的計(jì)算．                             

【專題】綜合計(jì)算（圖像型、表格型、情景型計(jì)算題）．                 

【分析】（1）由圖示可知生成的二氧化碳的質(zhì)量；                      

（2）根據(jù)化學(xué)方程式由二氧化碳的質(zhì)量可以求出碳酸鈉的質(zhì)量，進(jìn)而可以求出樣品中碳酸鈉的質(zhì)量分?jǐn)?shù)．          

【解答】解：（1）由圖示可知生成的二氧化碳的質(zhì)量為4.4g；            

故答案為：4.4；                                             

（2）解：設(shè)樣品中含Na₂CO₃的質(zhì)量為x                             

Na₂CO₃+2HCl=2NaCl+CO₂↑+H₂O                                      

106               44                                        

x                4.4g                                          

                                                            

                                                  

x=10.6g                                                     

該樣品中含碳酸鈉的質(zhì)量分?jǐn)?shù)為×100%=88.3%                     

答：該樣品中含碳酸鈉的質(zhì)量分?jǐn)?shù)為88.3%．                        

【點(diǎn)評(píng)】本題難度不大，掌握根據(jù)化學(xué)方程式與質(zhì)量分?jǐn)?shù)的綜合計(jì)算即可正確解答本題．