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【单选题】
函数<img class="kfformula" src="20190808/1565253438624934.png" data-latex="y=2-{x}^{2}"/>单调递减区间( )

<img class="kfformula" src="20190808/1565253438467999.png" data-latex="\left ( {-\infty ,0} \right )"/>
<img class="kfformula" src="20190808/1565253438403956.png" data-latex="\left ( {-\infty ,-1} \right )"/>
<img class="kfformula" src="20190808/1565253438303182.png" data-latex="\left ( {-1,+\infty } \right )"/>
<img class="kfformula" src="20190808/1565253438117832.png" data-latex="\left ( {0,+\infty } \right )"/>
【单选题】
关于维生素<img class="kfformula" src="20200424/1587719873847609.png" data-latex="{K}_{1}" width="39" height="26"/>描述,下列说法错误( )。

注射1~2h起效,3~6h止血效应明显,12~24h<img class="kfformula" src="20200424/1587719873825079.png" data-latex="PT" width="44" height="27"/>恢复正常
维生素<img class="kfformula" src="20200424/1587719873963754.png" data-latex="{K}_{1}" width="39" height="26"/>主要在胃内吸收
维生素<img class="kfformula" src="20200424/1587719873577601.png" data-latex="{K}_{1}" width="39" height="27"/>为促凝血因子合成药
维生素<img class="kfformula" src="20200424/1587719873539508.png" data-latex="{K}_{1}" width="39" height="27"/>缺乏可引起出血倾向凝血酶时间(<img class="kfformula" src="20200424/1587720020548019.png" data-latex="PT" width="42" height="27"/>)延长
有镇痛作用
【单选题】
P单质反应<img class="kfformula" src="20200629/1593418632407394.png" data-latex="4P+3KOH+{3H}_{2}O==={3KH}_{2}{PO}_{2}+{PH}_{3}" width="297" height="34"/>中变化(  )。

既被氧化又被还原
被氧化
既未被氧化又未被还原
被还原
【单选题】
设<img class="kfformula" src="20200624/1592994530966484.png" data-latex="{N}_{A}" width="49" height="27"/>为阿伏加德罗常数值,现有0.3mol/L<img class="kfformula" src="20200624/1592994530304513.png" data-latex="{K}_{2}{SO}_{4}" width="61" height="30"/>溶液,2L溶液中钾离子浓度为( )mol/L。

0.6
0.3
0.9
1.0
【单选题】
设<img class="kfformula" src="20200706/1594009368539359.png" data-latex="{N}_{A}" width="57" height="28"/>为阿伏加德罗常数值,现有0.3mol/L<img class="kfformula" src="20200624/1592993842192203.png" data-latex="{K}_{2}{SO}_{4}" width="51" height="31"/> 溶液,1L溶液中钾离子有( )<img class="kfformula" src="20200624/1592993842591471.png" data-latex="{N}_{A}" width="57" height="34"/>个。

0.6
0.3
1.0
0.9
【单选题】
不等式<img class="kfformula" src="20190808/1565250723184457.png" data-latex="{x}^{2}-2x-80"/>解集( )

<img class="kfformula" src="20190808/1565250723229267.png" data-latex="\left ( {4,+\infty } \right )"/>
<img class="kfformula" src="20190808/1565250723616994.png" data-latex="\left ( {-\infty ,-2} \right )\cup \left ( {4,+\infty } \right )"/>
<img class="kfformula" src="20190808/1565250723532354.png" data-latex="\left ( {-\infty ,-2} \right )"/>
<img class="kfformula" src="20190808/1565250723744347.png" data-latex="\left ( {-2,4} \right )"/>
【单选题】
<img class="kfformula" src="20200707/1594090277136567.png" data-latex="将足量Zn与5L0.1mol/L\, \, {H}_{2}{SO}_{4}溶液反应" width="370" height="32"/>,<img class="kfformula" src="20200706/1594022732803813.png" data-latex="可以生成(\, \, \, )mol氢气。\, \, " width="201" height="31"/>

22.4
11.2
2.24
1.12
【单选题】
用pH均为2盐酸醋酸溶液,分别中和等体积、等物质量浓度氢氧化钠溶液,当氢氧化钠恰好完全中和,消耗盐酸醋酸溶液体积分别为<img class="kfformula" src="20200629/1593410807763639.png" data-latex="{V}_{1}{V}_{2}" width="62" height="26"/>,则<img class="kfformula" src="20200629/1593410807313382.png" data-latex="{V}_{1}{V}_{2}" width="61" height="22"/>关系正确()。

<img class="kfformula" src="20200629/1593410807121645.png" data-latex="{V}_{1}{V}_{2}" width="65" height="36"/>
<img class="kfformula" src="20200629/1593410807286465.png" data-latex="{V}_{1}={V}_{2}" width="78" height="34"/>
<img class="kfformula" src="20200629/1593410807420867.png" data-latex="{V}_{1}\leq {V}_{2}" width="69" height="37"/>
<img class="kfformula" src="20200629/1593410807799986.png" data-latex="{V}_{1}{V}_{2}" width="73" height="29"/>
【单选题】
两条平行直线<img class="kfformula" src="20190809/1565322829875215.png" data-latex="3x+4y-7=0"/><img class="kfformula" src="20190809/1565322829154016.png" data-latex="3x+4y+8=0"/>之间距离( )

<img class="kfformula" src="20190809/1565322829886592.png" data-latex="3"/>
<img class="kfformula" src="20190809/1565322829721740.png" data-latex="3\sqrt {2}"/>
<img class="kfformula" src="20190809/1565322829406438.png" data-latex="15"/>
<img class="kfformula" src="20190809/1565322829833725.png" data-latex="\frac {1} {5}" width="87" height="63"/>
【单选题】
将0.lmol·<img class="kfformula" src="20200629/1593409309479184.png" data-latex="{L}^{-1}" width="46" height="31"/>醋酸溶液加水稀释,下列说法正确()。

溶液中c(<img class="kfformula" src="20200629/1593409309358634.png" data-latex="{H}^{+}" width="36" height="32"/>)c(<img class="kfformula" src="20200629/1593409309469275.png" data-latex="{OH}^{-}" width="55" height="27"/>)都减小
溶液中c(<img class="kfformula" src="20200629/1593409309586142.png" data-latex="{H}^{+}" width="45" height="26"/>)增大
醋酸电离平衡向逆反应方向移动
溶液pH增大