在四个相等容积的密闭容器中各自进行如下反应:2SO2(g)+O2(g) 2SO3

题型:选择题

问题:

在四个相等容积的密闭容器中各自进行如下反应:2SO2(g)+O2(g) 2SO3(g) △H<0,反应分别按以下条件进行,达到平衡后,c(SO2)最小的是

A.500℃,10molSO2 +5molO2

B.500℃,20molSO2 +5molO2

C.400℃,10molSO2 +5molO2

D.400℃,15molSO3分解

考点:化学平衡的有关计算影响化学平衡的因素达到化学平衡的标志化学平衡常数
题型:选择题
下列词语中加粗的字,读音全都正确的一组是
[ ]
A.通(dié)怨(mái)罪己(zhào)毛骨然(sǒng)
B.弃(bǐng)(hóng)热(jū)往知来(jiàn)
C.哭(tòng)旋(wò)马脚(lòu)时弊(biān)
D.击(jū)彩(hè)荒者(tuò)嘉言行(yí)
题型:选择题

When the Audet family turns on the lights at Blue Farm, they are using electricity that comes from cows—cow manure (粪肥), to be specific.

Cows produce a lot of wastes. One cow can create 30 gallons of wastes each day. Now imagine the output of over 1,000 cows at Blue Farm. That’s really a big amount.

When farmers clean their barns, they put the wastes in a big heap, and spread some of them on their fields for fertilizer(肥料). But now places like Blue Spruce Farm have a new way of using cow wastes. They use them to produce electricity.

Here’s how it works: A big machine moves back and forth cleaning the barn floor. “The cows aren’t bothered,” says Marie Audet. “They are animals of habit; they get used to it, and just lift one foot and then another to let it go by.”

The machine pushes the manure into a big 600-gallon tank like a small swimming pool. The tank is called a digester (化粪池) because what happens there is just like what happens inside a cow: Bacteria(细菌) get to work and continue to digest the manure.

Methane gas (甲烷、沼气)in the atmosphere is known as a “greenhouse” gas because it keeps heat just like a greenhouse does, causing our planet to warm up. That’s an environmental concern. But the digester has a good result. Its gas is kept and used to power electric generators (发电机).

At Blue Farm, the generators make enough electricity to power 400 homes. The Audet family sells the extra electricity they can’t use themselves.

小题1:We learn from the text that the Audet family is using cow wastes to ______.

A.make electricity

B.produce fertilizer

C.build their farm

D.feed the cows小题2:How are the cow wastes collected into the digester at Blue Farm?

A.Marie Audet does the work

B.The job is done by machine

C.The cows lift the cow wastes

D.Bacteria get to work on them小题3: According to the passage, which of the following is changed into electricity?

A.The power of moving water.

B.The heat of burning coal.

C.The power of sunlight.

D.The heat of the methane gas小题4:The new way of using cow wastes at Blue Farm might be best described as ______.

A.reducing

B.saving

C.recycling

D.changing小题5: What is the main purpose for writing the passage?

A.To introduce a new way of making electricity

B.To explain how a new energy works better

C.To show a new rebuilding plan for a big farm

D.To explain the reasons for green house effect

题型:选择题

精子与卵细胞相融合的现象,叫做(  )

A.授粉

B.受精

C.组织培养

D.无性生殖

题型:选择题

一匀强磁场分布在以O为圆心,半径为R的圆形区域内,方向与纸面垂直,如图所示,质量为m、电荷量q的带正电的质点,经电场加速后,以速度v沿半径MO方向进入磁场,沿圆弧运动到N点,然后离开磁场,∠MON=120°,质点所受重力不计,求:

(1)判断磁场的方向;

(2)该匀强磁场的磁感应强度B;

(3)带电质点在磁场中运动的时间.

题型:选择题

有关单纯疱疹病毒性脑炎影像学改变叙述错误的是()

A.脑部CT在起病后6~7天出现相应改变

B.脑部CT显示颞叶或以颞叶为中心累及额叶的边界不清的低密度影

C.脑部CT可显示占位效应

D.头颅MRI早期在T2加权像上可见颞叶和额叶底面周围边界清楚的高信号区

E.脑部CT在发病一周内可表现正常

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