题目

下面是一家服衣店的广告，请你配上一段话帮助店员(shop assistant)宣传，40词左右。Hualian Clothes Store 答案：Welcome to Hualian Clothes Store. Do you like this sweater? It's only $21 and it's very nice. These socks are only $3. This cap is only$8. These shorts are only $6. These pants are only $19. The shop assistants here are very friendly.对于3Fe（s）+4H2O（g） 高温 . Fe3O4（s）+4H2（g），若起始投入3mol铁、4mol水汽在体积为0.5L的密闭容器中反应，平衡时氢气的物质的量浓度4mol?L-1，则化学平衡常数为（　　） A、13B、16.75C、127D、1