差减法最适于称量下列哪种样品？（）A. 腐蚀天平盘的药品B. 粉末状样品C. 剧毒药品D. 易吸水、易被氧化、易与CO2作用的样品

色谱法利用混合物中各组分在互不相溶的两相之间的何种差异而使物质的各组分得到分离, 再对其进行定性或定量测定A. 质量B. 分配系数C. 分子量D. 溶解度E. 挥发性

[单选] 两只各装有1kg水的烧杯，一只溶有0.01mol蔗糖，另一只溶有0.01molNaCl，按同样速度降温冷却，则：（）A . 溶有蔗糖的杯子先结冰B . 两杯同时结冰C . 溶有NaCl的杯子先结冰D . 视外压而定

【单选题】药物分子中引入乙酰基,常用的乙酰化剂是 ()A. 乙酰氯 B. 乙醛 C. 乙醇 D. 乙酸

在下列相同浓度的溶液中, ^+ 浓度最大的是 () 。-|||-(A) ([ Ag{(CN))_(2)] }^- (B) ([ Ag{({S)_(2)(O)_(3))}_(2)] }^3--|||-(C) ([ Ag{(N{H)_(3))}_(2)] }^+ (D) ([ Ag{(en))_(2)] }^+

10.5 完成下列转化:-|||-a.-|||-OH-|||-b. (H)_(3)C(H)_(2)C(H)_(2)Brarrow C(H)_(3)C(H)_(2)C(H)_(2)COOH-|||-C. (C(H)_(3))_(2)CHOHarrow (C(H)_(3))_(2)CCOOH-|||-OH-|||-CH3 O-|||-O-|||-d.-|||-O-|||-CH3 O -0-|||-e. (C(H)_(3))_(2)C=C(H)_(2)arrow (C(H)_(3))_(3)CCOOH-|||-COOH-|||-f. 一-|||-g. equiv CHarrow C(H)_(3)COO(C)_(2)(H)_(5)-|||-h. 0-|||-i. (H)_(3)C(H)_(2)C(O)_(2)Harrow C(H)_(3)(C(H)_(2))_(3)COOH-|||-j.CH3 COOH- →CH2((COOC2H5 )2-|||-k. 0 CH2COONH4-|||-CH2CONH2-|||-CO2CH33 COOH-|||-1.-|||-OH O2CCH310.5 完成下列转化:-|||-a.-|||-OH-|||-b. (H)_(3)C(H)_(2)C(H)_(2)Brarrow C(H)_(3)C(H)_(2)C(H)_(2)COOH-|||-C. (C(H)_(3))_(2)CHOHarrow (C(H)_(3))_(2)CCOOH-|||-OH-|||-CH3 O-|||-O-|||-d.-|||-O-|||-CH3 O -0-|||-e. (C(H)_(3))_(2)C=C(H)_(2)arrow (C(H)_(3))_(3)CCOOH-|||-COOH-|||-f. 一-|||-g. equiv CHarrow C(H)_(3)COO(C)_(2)(H)_(5)-|||-h. 0-|||-i. (H)_(3)C(H)_(2)C(O)_(2)Harrow C(H)_(3)(C(H)_(2))_(3)COOH-|||-j.CH3 COOH- →CH2((COOC2H5 )2-|||-k. 0 CH2COONH4-|||-CH2CONH2-|||-CO2CH33 COOH-|||-1.-|||-OH O2CCH3

19.SiO2溶胶的胶团结构可表示为 ([ {(Si{O)_(2))}_(m)cdot n(S{O)_(3)}^2-cdot 2(n-x)(H)^+] }^2x--|||-(H)^+, 其中被称为胶粒的是 ()-|||-A.(SiO2)m B. ([ {(Si{O)_(2))}_(m)cdot n(S{O)_(3)}^2-cdot 2(n-x)(H)^+] }^2x--|||-C. ((Si{O)_(2))}_(m)cdot n(S{O)_(3)}^2- D. ((Si{O)_(2))}_(m)cdot n(S{O)_(3)}^2-cdot 2(n-x)(H)^+

实验中的过量化学品应当返回其原来的试剂瓶中以免浪费。-|||-A.错-|||-B.对

炉甘石洗剂中甘油的作用是（）A. 润湿剂B. 保湿剂C. 增溶剂D. 助悬剂E. 乳化剂

【单选题】活化能的概念是指:A. 底物和产物之间能量的差值 B. 活化分子所释放的能量 C. 分子由一般状态转变成活化状态所需能量 D. 温度升高时产生的能量 E. 以上都不是