n. [U] 1 a positive feeling that you have toward sb. or sth. that you consider to be good or suitable 赞成;赞许 2 official agreement or permission, given by sb. in authority 批准;核准;认可
【单选题】锌不但能与稀硫酸反应,还能与浓硫酸反应,现有一定质量的锌与浓硫酸在密闭器内发生反应,测得反应前后各物质的质量如下表所示,则下列有关X的说法中,正确的是( ) 物质 Zn H 2 SO 4 H 2 O ZnSO 4 X 反应前质量(g) 10.0 48.0 2.0 0 0 反应后质量(g) 3.5 28.4 5.6 16.1 x