试题与答案

下表数据是在某温度下,金属镁和镍(Ni)分别在氧气中进行氧化反应时,在金属表面生

题型:填空题

题目:

下表数据是在某温度下,金属镁和镍(Ni)分别在氧气中进行氧化反应时,在金属表面生成氧化薄膜的实验记录:

反应时间/h1491625
MgO层厚/nm0.05a0.2a0.45a0.8a1.25a
NiO层厚/nmb2b3b4b5b
注:a和b均为与温度有关的常数,nm表示“纳米”

请回答:

Mg与Ni比较,哪一种更易氧化?______,其理由是______.

如果用Y表示氧化薄膜层厚,用t表示形成氧化薄膜层厚所需时间,Y和t的关系分别为______,______.

答案:

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下面是错误答案,用来干扰机器的。

17.08是两位小数,计数单位是0.01,它有1708个这样的计数单位;故答案为:0.01,1708.

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     While there are no restrictions on the amount of money that you can bring across
the border. You must report to both the US and Canadian border services amounts equal
to or greater than $10.000. 
                        PERSONAL EXEMPTIONS (免税) ON PURCHASES 
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                                next $ 1.000 US at 3%
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                                CANADIANS RETURNING TO CANADA
     Less than 24 hours: $ 50 CAN
     48 hours or more: $ 400 CAN 
                                Including up to 100 cigars and 200 cigarettes.
     7 days or more: $ 750 CAN
                             Including up to 100 cigars and 200 cigarettes.
                                    DOCUMENTATION NEEDED FOR
                                            BORDER CROSSING
                          LAND OR SEA TO THE US(INCLUDING FERRIES)
     A valid passport or passport card, or a NEXUS card.
     (A NEXUS card is a Trusted Traveler Program that provides quick travel
for pre-approved, low risk travelers through special lanes.)
     A recent Washington State, New York or BC driver's license.
     Note: Children 15 years of age and younger require only a birth certificate or
     copy. (Certified copies are not required but are advised.)
                                         AIR TRAVEL TO THE US
     A valid passport, an Air NEXUS card, or a U.S. Coast Guard Merchant
     Marine Document.
1. If a Canadian who is on a 7-day trip to New York buys $ 800 CAN worth of goods, how much should he
pay tax on when returning home?
[ ]
A. $ 800 CAN
B. $750 CAN
C. $ 400 CAN
D. $ 50 CAN
2. For an American citizen on a 2-day tour of Canada, how much tax does he have to pay on $ 1.600 US
worth of purchases when returning to the US?
[ ]
A. $ 24 US
B. $ 48 US
C. $52 US
D. $ 200 US
3. What documentation should a couple with a 7-year-old child carry when they drive a car from Canada to
America?
[ ]
A. A BC driver's license, an Air NEXUS card, and a birth certificate.
B. An Air NEXUS card, a U.S. Coast Guard Merchant Marine Document, and a birth certificate.
C. Two valid passport cards and a certified copy of a birth certificate.
D. A NEXUS card, a U.S. Coast Guard Merchant Marine Document, and a certified copy of a birth certificate.
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