首页 > 远程教育> 国家开放大学

网友您好，请在下方输入框内输入要搜索的题目：

请输入或粘贴题目内容搜题

搜题

拍照、语音搜题，请扫码下载APP

题目内容（请给出正确答案）

[单选题]

The lower the temperature,()the liquid evaporates.

A.the more slower

B.the slower

C.the more fast

D.the faster

答案

查看答案

发布时间：2023-04-13

更多“The lower the temperature,()the liquid evaporates.”相关的问题

第1题

The higher the temperature,（)the liquid evaporates.A. the fasterB. fasterC. the slower

The higher the temperature,()the liquid evaporates.

A. the faster

B. faster

C. the slower

点击查看答案

第2题

The higher the temperature, _____the liquid evaporates.A.the fasterB.the more fastC.the

The higher the temperature, _____the liquid evaporates.

A.the faster

B.the more fast

C.the slower

D.the more slower

点击查看答案

第3题

The higher the temperature is, __________ the liquid evaporates.

A、the faster

B、faster

C、the slower

点击查看答案

第4题

If the temperature of the liquid is lower than the saturation temperature for the existing pressure ,it is called a （)liquid .

A.superheated

B.subcooled

C.saturated

D.dry saturated

E.dry saturated

点击查看答案

第5题

The difference between a liquid and a gas is obvious【46】______the conditions of temperatur

e and pressure commonly found at the surface of the Earth. A liquid can be kept in an open container and fills it to the level of a free surface. A gas forms no free surface but tends to diffuse throughout the space available; it must【47】______be kept in a closed container, as in the【48】______of a planet' s atmosphere. The distinction was a prominent feature of early theories【49】______(describe) the phases of matter. In the nineteenth century, for example, one theory maintained that a liquid could be "dissolved" in a vapor without losing its identity, and another theory held that the two phases are made up of different kinds of molecules (分子). The theories now prevailing【50】 t______a quite different approach by emphasizing what liquids and gases have in common. They are both forms of matter【51】______have no permanent structure , and they both flow easily. They are fluids.

The【52】______(fundament) similarity of liquids and gases becomes clearly apparent when the temperature and pressure are raised somewhat. Suppose a closed container partially filled with a liquid is heated. The liquid expands, or in other【53】______, becomes less dense; some of it evaporates. In contrast, the vapor above the liquid surface becomes dense as the evaporated molecules are added to it. The combination of temperature and pressure【54】______ which the densities become equal is called the critical point. Above the critical point the liquid and the gas can no longer be【55】______(distinguish) ; there is a single, undifferentiated fluid phase of uniform. density.

(35)

点击查看答案

第6题

The difference between a liquid and a gas is obvious under the conditions of temperature a

nd pressure commonly found at the surface of the Earth. A liquid can be kept in an open container and fill it to the level of a free surface. A gas forms no free surface but tends to dif fuse(扩散)throughout the space available; it must therefore be kept in a closed container or held by a gravitational field, as in the case of a planet's atmosphere. The distinction was a prominent feature of early theories describing the phases of matter. In the nineteenth century, for example, one theory maintained that a liquid could be "dissolved" in a vapor without losing its identity, and another theory that held the two phases are made up of different kinds of molecules: liquids and gases. The theories now prevailing take a quite different approach by emphasizing what liquids and gases have in common. They are both forms of matter that have no permanent structure, and they both flow readily. They are fluids.

The fundamental similarity of liquids and gases becomes clearly apparent when the temperature and pressure are raised somewhat. Suppose a closed container partially filled with a liquid is heated. The liquid expands, or in other words becomes less denser some of it evaporates. In contrast, the vapor above the liquid surface becomes denser as the evaporated molecules are added to it. The combination of temperature and press at which the densities be come equal is called the critical point. Above the critical point the liquid and the gas can no longer be distinguished; there is a single, undifferentiated fluid phase of uniform. density.

Which of the following would be the most appropriate title for the passage？

A．The Properities of Gases and Liquids.

B．What Fluids and Gases Are Made of.

C．New Uses for the Gas and the Liquid.

D．New Theories about Fluids and Gases.

点击查看答案

第7题

The higher the temperature, ()the liqud evaporates.

A.the slow

B.the more fast

C.the faster

D.the more slow

点击查看答案

第8题

The higher the temperature is, _______the liquid evaporates（蒸发).

A.the faster

B.faster

C.the slower

点击查看答案

第9题

When an alloy is at a temperature above the solidus but below the liquidus, it coexists as（).

A.Liquid

B.Gas

C.Solid

D.Plasma

点击查看答案

第10题

The use of heat pumps has been held back largely by skepticism about advertisers' claims t

hat heat pumps can provide as many as units of thermal energy for each unit of electrical energy used, thus apparently contradicting the principle of energy conservation. Heat pumps circulate a fluid refrigerant that cycles alternatively from its liquid phase to its vapor phase in a closed loop. The refrigerant, starting as a low-temperature, low-pressure vapor, enters compressor driven by an electric motor. The refrigerant leaves the compressor as a hot, dense vapor and flows through a heat exchanger called the condenser, which transfers heat from the refrigerant to a body or air. Now the refrigerant, as a high-pressure, cooled liquid, confronts a flow restriction which causes the pressure to drop. As the pressure falls, the refrigerant expands and partially vaporizes, becoming chilled. It then passes through a second heat exchanger, the evaporator, which transfers heat from the air to the refrigerant, reducing the temperature of this second body of air. Of the two heat exchangers, one is located inside, and the other one outside the house, so each is in contact with a different body of air: room air and outside air, respectively.

The flow direction of refrigerant through a heat pump is controlled by valves. When the refrigerant flow is reversed, the heat exchangers switch function. This flow-reversal capability allows heat pumps—either to heat or cool room air.

Now, if under certain conditions a heat pump puts out more thermal energy than it consumes in electrical energy, has the law of energy conservation been challenged？ No, not even remotely: the additional input of thermal energy into the circulating refrigerant via the evaporator accounts for the difference in the energy equation.

Unfortunately, there is one real problem. The heating capacity of a heat pump decreases as the outdoor temperature falls. The drop in capacity is caused by the lessening amount of refrigerant mass moved through the compressor at one time. The heating capacity is proportional to this mass flow rate: the less the mass of refrigerant being compressed, the less the thermal load it can transfer through the heat-pump cycle. The volume flow rate of refrigerant vapor through the single-speed rotary compressor used in heat pumps is approximately constant. But cold refrigerant vapor entering a compressor is at lower pressure than warmer vapor. Therefore, the mass of cold refrigerant—and thus the thermal energy it carries—is less than if the refrigerant vapor were warmer before compression.

Here, then, lies a genuine drawback of heat pumps: in extremely cold climates—where the most heat is needed—heat pumps are least able to supply enough heat.

The primary purpose, of the passage is to______

A．explain the differences in the working of a heat pump when the outdoor temperature changes

B．contrast the heating and the cooling modes of heat pumps

C．describe heat pumps, their use, and factors affecting their use

D．advocate the more widespread use of heat pumps

点击查看答案

第11题

Which of the following would lead to an increase in the vapor pressure of a liquid I. Increasing the temperature II. Adding a nonvolatile

A.I only

B.II only

C.Both I and II

D.Neither I nor II