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氢氧化铜悬浊液中存在如下平衡:Cu(OH)2 (s)⇌Cu2+(aq)+2OH﹣(aq),常温下其Ksp=c(Cu2+)•c2(OH﹣)=2×10﹣20mol2•L﹣2.

①某硫酸铜溶液里c(Cu2+)=0.02mol/L,如要生成Cu(OH)2沉淀,应调整溶液pH使之大于____.

②要使0.2mol/L硫酸铜溶液中Cu2+沉淀较为完全(使Cu2+浓度降至原来的千分之一),则应向溶液里加入氢氧化钠溶液使溶液pH为____.

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How to Build a Student's Self-Confidence

    Educating students means more than giving them academic knowledge. Simply knowing a correct response doesn't give a student the confidence to raise his hand to answer a question. Students perform best in constructive learning environments____Provide leadership opportunities for students. Cultivate (培养) important characteristics, including responsibility and independence by assigning students to take different classroom roles. Suitable jobs include hall monitors, audio-visual assistants and classroom helpers.____

Set achievable goals for each student.____Engage in ongoing dialogue regarding your expectations and their individual progress. Reward students for meeting challenges, while persuading struggling students back on track.

    Give constructive feedback to help reduce weaknesses and strengthen strengths. Teach students that self-confidence isn't built from being harmed by praise. Remain honest with each student to encourage them to speak out their problems, instead of avoiding or denying their existence. Make corrections without damaging your students' confidence.

    Encourage students to set high standards for themselves.____Reinforce(强化) this message with age-appropriate examples and literature. Provide consistent encouragement to students to show your commitment to their success.

    ____Realize that conquering difficult tasks builds mental toughness and fosters persistence. Relay this message to your students by asking each one to write a goal that focuses on improving a weak area. Help your students develop relevant attack plans.

A. Push students to improve their weaknesses.

B. Self-confidence games can help students of all ages.

C. Reassure students that they are capable of achieving greatness.

D. You can ease students' insecurities with various activities that build confidence.

E. They are especially useful in helping young children build success for their future.

F. Realize that overcoming self-doubt to achieve objectives helps build students' confidence.

G. Mastering some duties can help build confidence and erase fear of trying new experiences.