Δh<sub>a</sub>、Δh<sub>r</sub>、Δh<sub>c</sub>分别代表有效汽蚀余量、必需汽蚀余量、临界汽蚀余量,为了泵能避免发生汽蚀,要求()。
A、Δha≥Δhc
B、Δha≥Δhr
C、Δha≥100%Δhc(两者差值不小于0.5m)
D、Δha≥100%Δhr(两者差值不小于0.5m)
A、Δha≥Δhc
B、Δha≥Δhr
C、Δha≥100%Δhc(两者差值不小于0.5m)
D、Δha≥100%Δhr(两者差值不小于0.5m)
A、Δ<sub>rsub>H<sub>msub>=Δ<sub>rsub>G<sub>msub> B、Δ<sub>rsub>H<sub>msub>〉Δ<sub>rsub>G<sub>msub> C、Δ<sub>rsub>H<sub>msub>〈Δ<sub>rsub>G<sub>msub> D、三种均可能
A、Δ<sub>rsub>H<sub>msub>=Δ<sub>rsub>G<sub>msub> B、Δ<sub>rsub>H<sub>msub>>Δ<sub>rsub>G<sub>msub> C、Δ<sub>rsub>H<sub>msub><Δ<sub>rsub>G<sub>msub> D、三种均可能
A、ΔH=0 B、ΔH=C<sub>psub>(T<sub>2sub>-T<sub>1sub>) C、ΔH不存在 D、ΔH等于其他值
A、H<sub>2sub>O的标准生成热Δ<sub>fsub>H<sub>msub><sup>θsup> B、H<sub>2sub>(g)的标准燃烧热ΔcHm<sup>θsup>(H<sub>2sub>,g) C、H<sub>2sub>O(l)的标准生成热Δ<sub>fsub>H<sub>msub><sup>θsup>(H<sub>2sub>O,l) D、氢氧电池可逆热效应 E、以上均不对
A、Δ<sub>rsub>H<sup>θsup><sub>msub>〉0,Δ<sub>rsub>S<sup>θsup><sub>msub>〉0 B、Δ<sub>rsub>H<sup>θsup><sub>msub>〉0,Δ<sub>rsub>S<sup>θsup><sub>msub>〈0 C、Δ<sub>rsub>H<sup>θsup><sub>msub>〈0,Δ<sub>rsub>S<sup>θsup><sub>msub>〈0 D、Δ<sub>rsub>H<sup>θsup><sub>msub>〈0,Δ<sub>rsub>S<sup>θsup><sub>msub>〉0
A、λ<sub>1sub>〈λ<sub>2sub> B、λ<sub>1sub>〉λ<sub>2sub> C、λ<sub>1sub>=λ<sub>2sub> D、无法确定
A、K<sub>1sub><sup>øsup>=K<sub>2sub><sup>øsup>·(K<sub>4sub><sup>øsup>)2/K<sub>3sub><sup>øsup> B、K<sub>1sub><sup>øsup>=K<sub>2sub><sup>øsup>-K<sub>3sub><sup>øsup>+2K<sub>4sub><sup>øsup> C、K<sub>1sub><sup>øsup>=2K<sub>2sub><sup>øsup>·K<sub>3sub><sup>øsup>/K<sub>4sub><sup>øsup> D、lnK<sub>1sub><sup>øsup>=(K<sub>2sub><sup>øsup>-K<sub>3sub><sup>øsup>+2K<sub>4sub><sup>øsup>)
A、H<sub>1sub>、H<sub>2sub>A、H<sub>2sub>B、H<sub>3sub> B、H<sub>1sub>、H<sub>2sub>A、H<sub>2sub>B、H<sub>3sub>A C、H<sub>2sub>A、H<sub>2sub>B、H<sub>3sub>、H<sub>4sub> D、H<sub>2sub>A、H<sub>2sub>B、H<sub>3sub>A、H<sub>4sub>
A、△H<sub>1sub>+ △H<sub>2sub>+△H<sub>3sub> =△H<sub>4sub> B、△H<sub>1sub>+ △H<sub>2sub> = △H<sub>3sub> +△H<sub>4sub> C、(△H<sub>1sub>+ △H<sub>2sub>)-(△H<sub>3sub> +△H<sub>4sub>)=△H<sub>5sub> D、△H<sub>1sub>+△H<sub>2sub>+△H<sub>3sub>+△H<sub>4sub> =△H<sub>5sub>