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pH=4.66
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c Ka3=0.05¡Á1012.36=2.18¡Á10?14¡ÖKW, c/ Ka2=0.05/10?7.20¡·10 ËùÒÔH2OÀë½âµÄ¡²H?¡³Ïî²»¿ÉºöÂÔ£¬¼´KW²»ÄܺöÂÔ¡£ ¡²H?¡³=10?7.20*£¨0.05*10?12.36?10?14£©/0.05=2.00¡Á10?10
pH=9.70
14¡¢ÓûÅäÖÆpH=10.0µÄ»º³åÈÜÒº1L¡£ÓÃÁË16.0mol/L°±Ë®420mLÐè¼ÓNH4Cl¶àС
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ËùÒÔm(NH4Cl)= Ca¡¤V¡¤m=1.22 ¡Á1¡Á35 =65.4g ÒòΪCa>>[H+]- [OH-] Cb>>[OH-]-[H+] ËùÒÔ²ÉÓÃ×î¼òʽ¼ÆËãÊÇÔÊÐíµÄ. ´ð:Ðè¼Ó65.4g NH4CL¹ÌÌå¡£
15¡¢ÓûÅäÖÆ500 mL pH=5.0µÄ»º³åÈÜÒº£¬ÓÃÁË6 mol/L HAc 34 mL£¬ÐèÒªNaAc¡¤3H2O
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½â£º²é±íÖªHAcµÄpKa=1.8¡Á10-5
pH=5.0¼´[H+]=10-5 mol/L
6mol¡¤L?1?34mLc£¨HAc£©==0.41 mol/L
500mL--4.74
=10
-4
[H?][Ac?]¡ßKa=
[HAc]Ka[HAc]1.8?10?5?0.41¡à[Ac-]== =0.74 mol/L
[H?]10?5¡àmNaAc¡¤3H2O=136.1¡Á0.74¡Á1.5 =50.5 g
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1¡¢ÓÃ0.01000 mol¡¤L-1 HNO3ÈÜÒºµÎ¶¨20.00mL 0.01000 mol¡¤L-1 NaOH ÈÜҺʱ£¬»¯Ñ§¼ÆÁ¿µãpHΪ¶àÉÙ£¿»¯Ñ§¼ÆÁ¿µã¸½½üµÄµÎ¶¨Í»Ô¾Îª¶àÉÙ£¿Ó¦Ñ¡ÓúÎÖÖָʾ¼ÁָʾÖյ㣿
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0.01000mol/L?0.02mL-6
?5.00?10mol/L
20.00mL?19.98mL pH=8.70
µÎ¶¨Í»Ô¾ºó,¼ÓÈëHNO3ÈÜÒº19.98mL´ËʱÈÜÒºÖÐH+µÄŨ¶ÈΪ [H+]=
0.02mL?0.01000mol/L= 5.00?10-6 mol/L pH=5.30
20.00mL?20.02mL ËùÒԵζ¨Í»Ô¾µÄpHÖµ·¶Î§Îª8.70~5.30,ӦѡÔñÔÚ´Ë·¶Î§ÄÚ±äÉ«µÄָʾ¼Á£¬Èçäå°ÙÀï·ÓÀ¶,ÖÐÐÔºìµÈ
2¡¢Ä³ÈõËáµÄpKa£½9.21£¬ÏÖÓÐÆä¹²éî¼îNaAÈÜÒº20.00 mL£¬Å¨¶ÈΪ0.1000 mol/L£¬µ±ÓÃ0.1000 mol/L HClÈÜÒºµÎ¶¨Ê±£¬»¯Ñ§¼ÆÁ¿µãµÄpHΪ¶àÉÙ£¿»¯Ñ§¼ÆÁ¿µã¸½½üµÄµÎ¶¨Í»Ô¾Îª¶àÉÙ£¿Ó¦Ñ¡ÓúÎÖÖָʾ¼ÁָʾÖյ㣿
½â£ºËáµÄpKa=9.21,ÔòKa=6.2?10-10 Kb=Kw/Ka=1.6?10-5 CKb=1.6?10-6>10-8
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+-11
»¯Ñ§¼ÆÁ¿µãʱÉú³ÉHA[H]=CKa pH=-1/2lg3.13?10=5.26
»¯Ñ§¼ÆÁ¿µã¸½½üµÄµÎ¶¨Í»Ô¾,µÎ¶¨¼ÁÑÎËáµÄÁ¿Îª19.98mLʱ,ÈÜÒºÖÐÓÐÉú³ÉµÄHAºÍÊ£ÓàµÄNaA×é³É»º³åÈÜÒº C(HA)=
19.98mL?0.1mol/L0.02mL?0.1mol/L C(NaA)=
20.00mL?19.98mL20.00mL?19.98mL pH=pKa- lg(CHA / CNaA)=9.21- 3.0 = 6.21 µ±¹ýÁ¿0.02mLʱ [H+]=
0.02?0.1-5
mol/L=4.99?10 mol/L
20.00?20.02 pH=4.30,ͻԾ·¶Î§Îª6.21~4.30,Ӧѡ¼×»ùºì
P97 ˼¿¼Ìâ4-3 3¡¢±ê¶¨NaOH ÈÜҺʱ£¬Èô²ÉÓãº
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4 ÓÃÏÂÁÐÎïÖʱ궨HClÈÜҺŨ¶È: (1)ÔÚ110¡æºæ¹ýµÄNa2CO3
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(2)ÒòΪÅðÉ°º¬Óнᾧˮ,ÔÚ¿ÕÆøÖÐÏà¶Ôʪ¶ÈСÓÚ39%ʱ,»á·ç»¯Ê§Ë® ÔÚÏà¶Ôʪ¶ÈΪ30%µÄÈÝÆ÷Öб£´æ¹ýµÄÅðÉ° ¸ù¾Ý C(HCl)=
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6 ¡¢½ñÓû·Ö±ð²â¶¨ÏÂÁлìºÏÎïÖеĸ÷¸ö×é·Ö,ÊÔÄâ³ö²â¶¨·½°¸(°üÀ¨Ö÷Òª²½Öè,±ê×¼ÈÜÒº,ָʾ¼ÁºÍº¬Á¿¼ÆËãʽ,ÒÔg/mL±íʾ) (1)H3BO3+ÅðÉ° (2) HCl+NH4Cl
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2H+ + B4O7 + 5H2O = 4 H3BO3
1?CHCl?VHCl?mNa2B4O7?10?3¦ÑNa2B4O7 (g/mL)=2
V
¦ÑH3BO3 (g/mL)=
[(CV)NaOH?2(CV)HCl]?10?3
V(2)¢ÙÈ¡VmLHCl+NH4ClµÄ»ìºÏÒºÓÚ250mLµÄ׶ÐÎÆ¿Öв¢¼ÓÈë1~2µÎ¼×»ùºìָʾ¼Á
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