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1,��250mLȫ��b��,��

2��ӟ��b��(늠t),��

3,��25mL��50mL��ʽ�ζ��,��F��ƿ,��Һ��,��ƿ��,��

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1��t��⛘˜��Һ(C1/6K2Cr2O7=0.2500mol/L),��_�Qȡ�A(y��)��120��2h�Ļ��ʻ�(y��u)�|(zh��)��t��12.258g��ˮ��,��1000mL��ƿ��ϡ��˾�,��u��,��

2��ԇ��F�`ָʾҺ��Qȡ1.485g��_��(C12H8N2·H2O),��0.695g��၆�F(FeSO4·7H2O)��ˮ��,��ϡ��100mL,�A��ɫƿ�С�

3,��၆�F�@�˜��Һ[c(NH4)2Fe(SO4)2·6H2O≈0.1mol/L]��Qȡ39.5g��၆�F�@��ˮ��,��߅��߅��20mL��ᣬ��s��1000mL��ƿ��,��ˮϡ��˾�,��u��R��ǰ,��t��⛘˜��Һ�˶�,��

4��D��y��Һ��Qȡ5.0g��y��뵽500ml��,��һ��, ��r�u��ʹ��ܽ��,��

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6,��ṯ��Y(ji��)��ĩ,��

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�ʴ_��ȡ10.00mL��t��⛘˜��Һ��250mL�F��ƿ��,��ˮϡ��110mL��,��30mL��ᣬ�u��,��s��,��3��ԇ��F�`ָʾҺ(�s0.15mL)��၆�F�@��Һ�ζ�,��Һ��ɫ��Sɫ��(j��ng)�{�Gɫ��t��ɫ��K�c,��

C=(0.2500×10.00)/V

ʽ�У�C——��၆�F�@�˜��Һ�ĝ��(mol/L)��

V——��၆�F�@�˜��Һ��(mL),��

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1��ȡ20.00mL��Ͼ��ˮ�ӣ��m��ˮ��ϡ��20.00mL��250mLĥ�ڵĻ��F��ƿ��,��ʴ_��10mL ��t��⛘˜��Һ��(sh��)��С��ʯ,��B��ĥ�ڻ��ܣ��Ͽ��ؼ��30mL��-��y��Һ,��p�p�u��F��ƿʹ��Һ��,��ӟ��2h(��_ʼ��vӋ�r)��

��ڻ��W(xu��)��ߵďUˮ��,��ȸ��(j��)�y�ďUˮ��,��x��ϡጱ��(sh��)��ϡጺ�Uˮ�Н��50��200mg/L��,��ϡጕr,��ȡ�Uˮ��5mL��W(xu��)��ܸ�,��t�Uˮ�ӑ�(y��ng)��ϡ�,��Uˮ��x�Ӻ��^30mg/L�r��(y��ng)�Ȱ�0.4g��ṯ��F��ƿ��,��ټ��20.00mL�Uˮ��m��Uˮϡ��20.00mL��,��u��

2,��s��,��90.00mLˮ�_ϴ��ܱڣ�ȡ��F��ƿ��Һ��w�e��140mL,��t��̫��,��ζ��K�c��@��

3,��Һ�ٶ��s��,��3��ԇ��F�`ָʾҺ��၆�F�@�˜��Һ�ζ�,��Һ��ɫ��Sɫ��(j��ng)�{�Gɫ��t��ɫ��K�c,��ӛ��၆�F�@�˜��Һ��

4,��y��ˮ�ӵ�ͬ�r,��ȡ20.00mL��sˮ��ͬ�Ӳ��E��հ׌��,��ӛ䛵ζ��հוr��၆�F�@�˜��Һ��,��

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CODCr(O2,��mg/L)=8×1000(V0-V1)·C/V

ʽ�У�C——��၆�F�@�˜��Һ�ĝ��(mol/L),��

V0——�ζ��հוr��၆�F�@�˜��Һ��(mL)��

V1——�ζ�ˮ�ӕr��၆�F�@�˜��Һ��(mL),��

V——ˮ�ӵ��w�e(mL),��

8——��1/2O��Ħ��|(zh��)��g/mol��

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1,��ʹ��0.4g��ṯ�j(lu��)��x�ӵ��_40mg,��ȡ��20.00mLˮ��,��߿ɽj(lu��)��2000mg/L��x�ӝ�ȵ�ˮ�ӡ��x�ӵĝ��^��,��Ҳ��ټ��ṯ,��ʹ��ṯ:��x��=10:1(W/W)��F(xi��n)��Ȼ��,��Ӱ표y��,��

2��ˮ��ȡ��w�e��10.00—50.00mL��(n��i),��ԇ��谴�±��M��(y��ng)�{(di��o)��,��Ҳ�ɵõ��M��ĽY(ji��)��

ˮ��w�e	0.25000mol/L	H₂SO₄-Ag₂SO₄	HgSO₄	[(NH₄)₂Fe(SO₄)₂]	�ζ�ǰ��
(mL)	K₂Cr₂O₇��Һ��mL��	��Һ��mL��	(g)	(mol/L)	�w�e��mL��
10	5	15	0.2	0.05	70
20	10	30	0.4	0.1	140
30	15	45	0.6	0.15	210
40	20	60	0.8	0.2	280
50	25	75	1	0.25	350

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3,��ڻ��W(xu��)��С��50mg/L��ˮ��,��(y��ng)��0.0250mol/L��t��⛘˜��Һ��صΕr��0.01mol/L��၆�F�@�˜��Һ,��

4,��ˮ�Ӽӟ��Һ��t��ʣ��(y��ng)��1/5—4/5��,��

5,��⛘˜��Һ�z��ԇ��|(zh��)��Ͳ��g(sh��)�r��ÿ��⛵��ՓCODCr��1.176g,��ܽ�0.4251g��(HOOCC6H4COOK)��sˮ��,��D(zhu��n)��1000mL��ƿ,��sˮϡ��˾��ʹ֮�ɞ�500mg/L��CODcr�˜��Һ,��Õr��,��

6��CODCr�Ĝy��Y(ji��)��(y��ng)��λ��Ч��(sh��)��,��

7,��ÿ�Ό��r��(y��ng)��၆�F�@�˜ʵζ��Һ�M�И˶�,��Ҝ��^�ߕr��ע��ȵ�׃��,��

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