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问题 问答题

拟用实验方法除去下列（1）～（4）中各物质中的少量杂质，限从A～D提供的试剂及操作方法中进行选择，并将其序号填在相应的短线上．

A．加适量的稀盐酸，搅拌、蒸发、结晶

B．加适量的稀盐酸，搅拌、过滤、洗涤、沉淀

C．加适量的水，溶解、过滤、洗涤、沉淀

D．加适量的水，溶解、过滤、蒸发、沉淀

（1）碳酸钙中混有少量杂质碳酸钠 ______；

（2）铜粉中混有少量杂质锌粉 ______；

（3）氯化钠中混有少量杂质碳酸钠 ______；

（4）氯化钾中混有少量杂质二氧化锰 ______．

答案

（1）碳酸钙是不溶于水的物质，碳酸钠易溶于水，所以可以根据这两种物质的溶解性采用加水的方法把碳酸钠除掉，加水后碳酸钠溶解在水中，通过过滤可以将其除掉，然后将得到的沉淀进行洗涤就可以得到纯净得碳酸钙，所以本题答案为：C；

（2）根据金属活动性顺序，排在氢前的锌可以与酸发生置换反应，而排在氢后的铜不能与酸发生置换反应，根据这两种物质是否与酸发生置换反应可以采用加酸的方法，使锌参加反应，经过滤得到铜，再进行洗涤即可得到纯净的铜，所以本题答案为：B；

（3）碳酸钠可以与盐酸反应生成氯化钠，要将得到的氯化钠从溶液中析出，需把水蒸发掉，使氯化钠结晶析出，所以本题答案为：A；

（4）氯化钾易溶于水，而二氧化锰不溶于水，所以可以根据这两种物质的溶解性采用加水的方法，使氯化钾溶于水，经过过滤除掉二氧化锰，要将得到的氯化钾从溶液中析出，需把水蒸发掉，使氯化钾结晶析出，所以本题答案为：D．

阅读理解

Bugs Bunny's Hoping Carrot Hunt
In this game you are Bugs Bunny．and your goal is to reach the finish line．A carrot truck has spilled its cargo! Gather as many carrots as you can, and when you get the big carrot, you'll be able to jump even higher!
Instructions: Use the mouse to move Bugs left and right, and click to jump a gap while   gathering carrots．
Category: Action 
 
Mushroom Madness
You are in charge of protecting several farms．It's up to you to make sure the mushrooms there reach maturity before the animals in the forest get their hands on them．Use your swatter（苍蝇拍）to fight off anything that comes near them; use heavier weapons if necessary．
Instructions：Slap any creature that conies near your mushrooms．Use the mouse to control the swatter．If you see a "power up", click to use it．Collect coins to buy upgrades after each level．
Category: Action
 
Rudolph's Kick and Fly
Santa's little helpers have worked all year preparing for Christmas．When Santa finally leaves to deliver his presents, the elves(精灵）head down to the snowfields with Rudolph, the reindeer, to play their favorite game: Kick and Fly!
Instructions:  1.Use the mouse to aim, and click to launch an elf．
2.While in the air, click again to catch, and to gain extra height．
3.The goal is to collect as many Christmas ornaments（装饰物）possible, and get 10    points for each one．
Tips: If you're heading towards an obstacle(障碍), be sure to avoid it!
Category: Action 
 
Click Flick
Your mission is to save chicks falling from the sky．Use your trampoline （蹦床） to bounce them up and direct them into a nest．But hurry—if you don't, many chicks will fall and lose their lives．There will be falling bombs, worms, nuts and eggs and you can get extra points by collecting the worms and nuts．Save the amount of chicks shown to unlock the next level!
Instructions: Move the chicks left and right using keys or the mouse．
Category: Adventure
 
小题1:The main purpose of the passage is to ___________．
A．tell us different categories of games
B．ask us to decide which game is the best
C．introduce several interesting computer games
D．let us evaluate whether we are interested in the games
小题2:If a player has collected some worms and nuts, he ____________．
A．is playing Mushroom MadnessB．will lose the game quite soon
C．will get 10 points for each oneD．will get extra points and get ahead
小题3:Which of the following statements about the games is TRUE according to the
passage?
A．Bugs Bunny needs to be fast to win．
B．All four games are in the same category．
C．Players can only use the mouse to control the targets．
D．The number of elves decides whether a player wins in Rudolph's' Kick and Fly．
小题4:If a player wants to become stronger to drive animals away, he should try to _____．
A．find a "power up" or use heavier weapons
B．collect falling bombs as quickly as possible
C．click the elf while it's in the air
D．get the big carrot while running
小题5:In which game are there obstacles you must avoid?
A．Bugs Bunny's Hopping Carrot Hunt．B．Mushroom Madness．
C．Rudolph's Kick and Fly．D．Click Flick．
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单项选择题

物质的量表示物质指定的（）是多少的物理量。

A、基本单位

B、基本单元

C、原子数量

D、分子数量
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