问题 实验题

某学习小组用下图装置测定铝美合金中铝的质量分数和铝的相对原子质量

(1)A中试剂为__________

(2)实验前,先将铝镁合金在稀酸中浸泡片刻,其目的是__________

(3)检查气密性,将药品和水装入各仪器中,连接好装置后,需进行的操作还有:

①记录C的液面位置;

②将B中剩余固体过滤,洗涤,干燥,称重;

③待B中不再有气体产生并恢复至室温后,记录C的液面位置;

④由A向B中滴加足量试剂;

⑤检查气密性,上述操作的顺序是__________;(填序号)记录C的液面位置时,除视线平视外,还应

__________________。

(4)B中发生反应的化学方程式为____________________。

(5)若实验用铝镁合金的质量为a g,测得氢气体积为b mL(已换算为标准状况),B中剩余固体的质量为cg,则铝的相对原子质量为__________

(6)实验过程中,若未洗涤过滤所得的不溶物,则测得铝的质量分数将__________(填“偏大”、“偏小”、“不受影响”)

答案

(1)NaOH溶液.

(2)除去铝镁合金表面的氧化膜.

(3)⑤①④③②;使D和C的液面相平

(4)2Al+2NaOH+2H2O=2NaAlO2+3H2↑或2Al+2OH-+2H2O=2AlO2-+3H2

(5)

(6)偏小

单项选择题

(B)

Disney’s cartoon, Finding Nemo, tells a touching story of a father called Martin and his son Nemo.

Martin loses his wife and an entire family of unhatched eggs to a huge shark. Only one fish egg remains, Nemo. Martin promises his dead wife that he will protect his young son at any cost. So, Martin becomes fearful of almost everything in the ocean. That makes him over protective-he hopes to keep his kid safe from the challenges that life presents. Martin’s nagging (唠叨) makes Nemo feel that he doesn’t need his dad telling him what to do.

So on his first day of school, Nemo and some friends swim to the edge of their coral reef, a place Martin always thinks is very dangerous. When Martin shouts at Nemo come back, Nemo refuses to listen to him and swim out to a boat in the distance. Suddenly, he gets caught by some divers. So begins Martin’s journey to find Nemo, who ends up in an aquarium in an office in Australia. Soon the worried father runs into Dory, a forgetful blue fish, who helps Martin find his son. Meanwhile, Nemo misses his father terribly. He soon hears that he will be given to an eight-yearold girl who likes to kill fish.

Can Martin find his son before it is too late

Finding Nemo is a physical and mental journey. Martin overcomes his shyness and anxieties and Nemo discovers his own and his father’s hidden strengths. It celebrates the relationship between fathers and their sons.

The cartoon paints a sea world that is alive with color. All the characters are very human-like and have their own personalities.

Finding Nemo was released in the US on may 30, earning about US $70.6 million in just three days, it has set a new opening records for a cartoon.

Which of the following statements is true according to the second paragraph()

A. Martin’s wife and most of his children died because of disease.

B. Martin is a coward that he is afraid of everything.

C. Nemo has grown up and doesn’t need his father’s protection any longer.

D. Martin loves his son so much that he becomes so protective.

单项选择题