燃气燃烧时需要消耗氧气，1立方天然气完全燃烧理论上需要消耗立方空气，因此燃具应安装在通风良好的场所（）

B．7

C．29

D．10

B.5.5

C.9.52

D.10

单位天然气（通常是1m³）完全燃烧所放出的热量叫天然气的热值。

A. 0.8~1

B. 1~1.1

C. 1.1~1.3

天然气和空气混合，当天然气浓度在一定范围内时，遇明火就会发生燃烧和爆炸。燃烧时，燃烧波的传播速度较慢，约0.3～2.4m/s，而爆炸时，会迅即产生高压高温，波速达到1000～3000m/s，对管线和容器的破坏力很大。天然气产生爆炸的浓度范围为5～15％，随温度、压力升高，爆炸浓度的上限提高，爆炸范围扩大。Natural gas and air mix, when the concentration of natural gas within a certain range, open fire will occur combustion and explosion. In combustion, the propagation speed of combustion wave is slow, about 0.3 ~ 2.4m/s, while in explosion, the high pressure and temperature will be generated immediately, and the wave speed reaches 1000 ~ 3000m/s, which is very destructive to pipelines and containers. The explosion concentration range of natural gas is 5 ~ 15%. With the increase of temperature and pressure, the upper limit of explosion concentration increases and the explosion range expands.

A. 相同

B. B.有时快，有时慢

C. C.快

D. D.慢

B．轻，重

C．轻，轻

D．重，轻

B．0.08-0.12MPa

C．0.05-0.10MPa

D．0.08-0.10MPa

此题为判断题(对，错)。