题目

       Mars( 火星) appears to be flowing with small streams of salty water, at least in the  summer,  scientists reported Monday.  It suggests that. it would be possible for there to  be life today on Mars, NASA's science mission chief, John Grunsfeld, said at a news conference on September 28, 2015.       The streams are about 12 to 15 feet wide and 300 feet or more long, scientists said.  What we're dealing with is wet soil. thin layers of wet soil, not standing water, said Aifred McEwen of the University of Arizona at Tueson ! the principal scientist for the Mars 3.04 g铜镁合金完全溶解于100 mL 14.0 mol/L的浓硝酸中，得到NO2和N2O4的混合气体2 240 mL(标准状况)，向反应后的溶液中加入2.0 mol/L NaOH溶液，当金属离子全部沉淀时，得到5.08 g沉淀。下列说法不正确的是( )A．该合金中铜与镁的物质的量之比是2∶1B．被还原的硝酸的物质的量是0.12 molC．得到5.08 g沉淀时，加入NaOH溶液的体积是700 mLD．NO2和N2O4的混合气体中，NO2的体积分数是80%