【单选题】
不等式<img class="kfformula" src="20190808/1565250723184457.png" data-latex="{x}^{2}-2x-80"/>的解集是( )
①
<img class="kfformula" src="20190808/1565250723229267.png" data-latex="\left ( {4,+\infty } \right )"/>
②
<img class="kfformula" src="20190808/1565250723616994.png" data-latex="\left ( {-\infty ,-2} \right )\cup \left ( {4,+\infty } \right )"/>
③
<img class="kfformula" src="20190808/1565250723532354.png" data-latex="\left ( {-\infty ,-2} \right )"/>
④
<img class="kfformula" src="20190808/1565250723744347.png" data-latex="\left ( {-2,4} \right )"/>
【单选题】
<img class="kfformula" src="20190808/1565256297772060.png" data-latex="\sqrt {\left ( {lg5-1} \right )^{2}}"/>的值等于( )
①
<img class="kfformula" src="20190808/1565256297983776.png" data-latex="lg\frac {1} {5}"/>
②
<img class="kfformula" src="20190808/1565256297148379.png" data-latex="lg5-1"/>
③
<img class="kfformula" src="20190808/1565256297764160.png" data-latex="lg5"/>
④
<img class="kfformula" src="20190808/1565256297303551.png" data-latex="lg2"/>
【单选题】
<img class="kfformula" src="20200624/1592998127855778.png" data-latex="{Ba(OH)}_{2}" width="66" height="31"/>·<img class="kfformula" src="20200624/1592998127449837.png" data-latex="{8H}_{2}0" width="60" height="28"/>晶体与<img class="kfformula" src="20200624/1592998127342306.png" data-latex="{8H}_{2}0" width="67" height="28"/>晶体的反应,是( )。
【单选题】
欲使0.1mol/L的<img class="kfformula" src="20200629/1593414371655621.png" data-latex="{CH}_{3}COONa" width="110" height="34"/>溶液中,c(<img class="kfformula" src="20200629/1593414371705821.png" data-latex="{Na}^{+}" width="58" height="33"/>)/c(<img class="kfformula" src="20200629/1593414371315923.png" data-latex="{CH}_{3}{COO}^{-}" width="118" height="34"/>)更接近于1:1 ,应采取的措施是()。
③
加入适量<img class="kfformula" src="20200629/1593414371383535.png" data-latex="{CH}_{3}COOH" width="98" height="30"/>
【单选题】
欲使0.1mol/L的<img class="kfformula" src="20200629/1593414655316335.png" data-latex="NaH{CO}_{3}" width="77" height="33"/>溶液中c(<img class="kfformula" src="20200629/1593414655655850.png" data-latex="{H}^{+}" width="39" height="28"/>)、c(<img class="kfformula" src="20200707/1594094658266332.png" data-latex="{{CO}_{3}}^{2-}" width="77" height="37"/>)、c(<img class="kfformula" src="20200706/1594030018177834.png" data-latex="{HC{O}_{3}}^{-}" width="80" height="36"/>)都减小,其方法是()。
【单选题】
已知直线过点<img class="kfformula" src="20190809/1565321501439277.png" data-latex="\left ( {\sqrt {3},-3} \right )"/>,且倾斜角为30°,则直线的方程是( )
①
<img src="20190809/1565321420131356.png" title="1565321420131356.png" alt="图片49.png"/>
②
<img src="20190809/1565321484569743.png" title="1565321484569743.png" alt="图片50.png"/>
③
<img src="20190809/1565321493966443.png" title="1565321493966443.png" alt="图片51.png"/>
④
<img src="20190809/1565321498657079.png" title="1565321498657079.png" alt="图片52.png"/>
【单选题】
今有360本图书借给学生阅读,每人9本,则余下的书数<img class="kfformula" src="20190924/1569292387333325.png" data-latex="y"/>(本)和学生数<img class="kfformula" src="20190924/1569292387869597.png" data-latex="x"/>(个)之间的函数关系式为( )
①
<img class="kfformula" src="20190924/1569292387325349.png" data-latex="y=40/x"/>
②
<img class="kfformula" src="20190924/1569292387912197.png" data-latex="y=9*x"/>
③
<img class="kfformula" src="20190924/1569292387266041.png" data-latex="y=360-9x"/>
④
<img class="kfformula" src="20190924/1569292387456376.png" data-latex="y=360+9x"/>
【单选题】
设<img class="kfformula" src="20200624/1592994110275229.png" data-latex="{N}_{A}" width="43" height="27"/>为阿伏加德罗常数的值,现有0.3mol/L<img class="kfformula" src="20200624/1592994110834086.png" data-latex="{K}_{2}{SO}_{4}" width="63" height="30"/>溶液,1L溶液中<img class="kfformula" src="20200707/1594086644585029.png" data-latex="{S{O}_{4}}^{2-}" width="68" height="32"/>有( )<img class="kfformula" src="20200624/1592994110685297.png" data-latex="{N}_{A}" width="49" height="27"/>个。
【单选题】
计算<img class="kfformula" src="20200624/1592993098219071.png" data-latex="{71gC1}_{2}" width="79" height="31"/>所含原子数为( )<img class="kfformula" src="20200624/1592993098786896.png" data-latex="{N}_{A}" width="43" height="33"/>。
【单选题】
如果25℃时Kw=<img class="kfformula" src="20200629/1593410268481104.png" data-latex="1\times {10}^{-14}" width="63" height="39"/>,100℃时Kw=<img class="kfformula" src="20200629/1593410268882824.png" data-latex="1\times {10}^{-12}" width="75" height="29"/>,这说明().
④
前者c(<img class="kfformula" src="20200629/1593410268511436.png" data-latex="{H}^{+}" width="46" height="24"/>)较后者大