2021-2022学年八年级全一册化学鲁教版（五四制）暑假提前学（8）物质组成的表示
※题型：单选题※知识点：单选题※试题难度：容易<br>“84”消毒液的主要辟分是次氯酸钠(NaClO)。NaClO中氯元素的化合价为( )<br>A.-1 B.+1 C.+5 D.+7<br>答案<br><img src="https://picture2.zhihuicn.com/answer/2/5/2021/08b7b75aff154ad29bc6fcc4a70169a0/76900E09FAB5EBA344B8EA84E844FF07.png"><br>解析<br>略<br>※题型：单选题※知识点：单选题※试题难度：中等<br>偏钛酸钡(<img src="https://picture2.zhihuicn.com/testImage/2/2020/9/25/9B3D69D776620681ABCAE47B77695522.png"><br>)因其显著的“压电效应”而广泛应用于超声波发生装置中。已知偏钛酸钡中钛元素的化合价为+4价,则其化学式中x的数值是( )<br>A.1 B.2 C.3 D.4<br>答案<br><img src="https://picture2.zhihuicn.com/answer/2/5/2020/ad40a40a284f4e4da1f7bbae387be1de/06CA09E70C17EF8BA2D3B8C70D693953.png"><br>解析<br>略<br>※题型：单选题※知识点：单选题※试题难度：较易<br>由<img src="https://picture2.zhihuicn.com/testImage/2/2021/6/25/729CC357F6ED9DCC7007D48684A026F2.png"><br>组成的混合物中,碳元素的质量分数为60%,则与氧元素的质量分数最接近的是( )<br>A.31% B.32% C.33% D.35%<br>答案<br><img src="https://picture2.zhihuicn.com/answer/2/5/2021/fc69667376434b4dabd9228743b270bb/E7F0EDF83F40244C8F0C84B97471AED6.png"><br>解析<br><img src="https://picture2.zhihuicn.com/explain/2/5/2021/c25f00f7adf3474eb3df814bc6290794/A4D5FA003DEC7F1A36DD7B96D7C07792.png"><br><br>※题型：填空题※知识点：填空题※试题难度：较易<br>乙醇(<br><img src="https://picture2.zhihuicn.com/testImage/2/2020/9/18/3F07E94D7ECB10A9E43EEDDD27705AA4.png"><br>)可用作燃料。按要求计算。<br>1.乙醇分子中C、H、O原子个数比为。<br>2.乙醇中碳元素和氢元素的质量比为(写最简比)。<br>3.乙醇的相对分子质量为。<br>4.9.2g的乙醇中含有碳元素的质量为g。<br>答案<br><img src="https://picture2.zhihuicn.com/answer/2/5/2020/5da86c97ab654429a452ae4108fe4c52/06BAEF9C601131A644D7B5B1B24D0C90.png"><br>解析<br><img src="https://picture2.zhihuicn.com/explain/2/5/2020/6bee1b87b421453d81a5fc5dbe814c14/3FCA99A228E3B056C035934E14AF9432.png"><br><br>
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