1/5单选题
难度：
1.有一瓶20g的氯化钾溶液，蒸干后得到了2.8g氯化钾固体。请问这一溶液中溶质的质量分数。
| A | 20% |
| B | 18% |
| C | 14% |
| D | 16% |
- 提示1：
- IDxpbWcgd2lkdGg9MjE2IGhlaWdodD00NiBzcmM9Imh0dHBzOi8vcDIucWluZ2d1by5jb20vRzEvTTAwLzM0LzI4L3JCQUNFMU1TLUx5d3hVTUNBQUFEWWl3aHN0TTg5Ny5wbmciPg==
正确答案：Qw==
5rq26LSo55qE6LSo6YeP5YiG5pWw5Li677yaMi44LzIww5cxMDAlPTE0JTxicj48YnI+
2/5单选题
难度：
2.
小欢通过计算发现，上述3次实验中，第几次数据是错误的？
小亮和小欢同学对铜与氧气反应的产物进行探究：小欢把加热后的铜丝A与过量稀硫酸反应，发现加热后生成的黑色物质B全部溶解，得到红色物质C。将C洗涤、干燥，称得质量为9.6g。小亮认为还可测出稀硫酸的质量分数。以下是他的测定方法：每次取16g铜丝，加热后质量为m1，逐滴加入稀硫酸与其反应，使黑色固体还有剩余。取出剩余固体，洗涤、干燥，称其质量为m2，并由反应前后溶液质量的变化计算出参加反应的稀硫酸质量m3。小亮经三次实验，记录实验数据如下表，计算出稀硫酸的质量分数为49％。
 | m1（g） | m2（g） | m3（g） |
| 第1次 | 17 | 13 | 10 |
| 第2次 | 19 | 11 | 20 |
| 第3次 | 22 | 6 | 40 |
| A | 第一次 |
| B | 第二次 |
| C | 第三次 |
| D | 没有错误数据 |
- 提示1：
- PHA+Q3XliqDng63lkI7nlJ/miJDnmoTpu5HoibLniankvZNC5Li6Q3VP44CC5oqK6buR6Imy55qE54mp6LSo5rq26Kej5o6J5LmL5ZCO5Ymp5L2Z55qE57qi6Imy54mp6LSo77yM5oiR5Lus5Y+v5Lul5Yik5pat5Li65rKh5pyJ6KKr5Y+N5bqU5o6J55qE6ZOc44CCPC9wPg==
- 提示2：
- PHA+5YGH5aaC5pyJ6ZSZ6K+v55qE5pWw5o2u77yM6YKj5LmI6ZSZ6K+v55qE5qC55rqQ5bqU6K+l5Zyo56ys5LiA5qyh55qE6LSo6YeP5Y2zbTxzdWI+MTwvc3ViPu+8jOaJgOS7peaIkeS7rOWPquimgeeul+WHujE2Z+mTnOacgOWkmuiDveeUn+aIkOeahOawp+WMlumTnOeahOi0qOmHj+WNs+WPr+i/m+ihjOWIpOaWreOAgjwvcD4=
- 提示3：
- PHA+57uP6L+H6K6h566XbTHlsLHlvojlrrnmmJPlj5HnjrDplJnor6/llaZ+PC9wPg==
正确答案：Qw==
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
3/5单选题
难度：
3.
只含铜、氧两种元素的固体样品9.0g，测得其中含铜元素的质量为8.0g。已知铜有CuO和Cu2O两种氧化物，且均为固体。下列说法不正确的是
| A | 固体样品可能是Cu2O |
| B | 固体样品的物质成分组合只有2种情况 |
| C | 固体样品可能是Cu、CuO与Cu2O的混合物 |
| D | 若固体样品中只含两种物质，则两种物质的质量比可能为5︰4 |
- 提示1：
- PHA+QUJD5qC55o2u5bey55+l5p2h5Lu26K6h566X5Ye65qC35ZOB5Lit5ZCr6ZOc5YWD57Sg55qE6LSo6YeP5YiG5pWw77yM54S25ZCO5YaN5YiG5Yir6K6h566X5Ye6Q3VP5ZKMQ3U8c3ViPjI8L3N1Yj5P5Lit6ZOc5YWD57Sg55qE6LSo6YeP5YiG5pWw77yM5o2u5q2k5YiG5p6Q5qC35ZOB55qE57uE5oiQ55qE5oOF5Ya177yb5oqKQ3XnmoTpk5zlhYPntKDotKjph4/liIbmlbDnnIvlgZoxMDAl44CCPC9wPg==
- 提示2：
- PHA+ROS7juagt+WTgeeahOe7hOaIkOeahOaDheWGteS4reaJvuWHuuWPquWQq+S4pOenjeeJqei0qOeahOaDheWGte+8jOe7k+WQiOeJqei0qOeahOWMluWtpuW8j+i/m+ihjOiuoeeul++8jOWNs+WPr+W+l+WHuuS4pOenjeeJqei0qOeahOi0qOmHj+avlC48L3A+
正确答案：Qg==
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
4/5单选题
难度：
4.
为测定一瓶放置已久的烧碱中NaOH含量，某同学取适量的烧碱样品，溶于一定量的水，得到200g溶液，再加入200g稀硫酸(足量)充分搅拌到不再放出气泡为止，称量溶液为395.6g。请计算或回答：若所取样品为50.0g，则样品中NaOH的质量分数是多少？
| A | 78.8% |
| B | 76.8% |
| C | 77.8% |
| D | 79.8% |
- 提示1：
- PHA+5Yip55So6LSo6YeP5a6I5oGS5a6a5b6L77yM5qC55o2u5Y+N5bqU5YmN5ZCO54mp6LSo5oC76LSo6YeP55qE5beu5Y+v6K6h566X5pS+5Ye65LqM5rCn5YyW56Kz55qE6LSo6YeP44CCPC9wPg==
- 提示2：
- PHA+5Yip55So5a6M5YWo5Y+N5bqU5pS+5Ye65LqM5rCn5YyW56Kz55qE6LSo6YeP77yM5qC55o2u5Y+N5bqU55qE5YyW5a2m5pa556iL5byP77yM5Y+v6K6h566X5Ye65qC35ZOB5Lit56Kz6YW46ZKg55qE6LSo6YeP44CCPC9wPg==
- 提示3：
- PHA+55Sx5qC35ZOB6LSo6YeP5LiO56Kz6YW46ZKg6LSo6YeP55qE5beu5LiO5qC35ZOB6LSo6YeP55u45q+U77yM5rGC5Ye65qC35ZOB5LitTmFPSOeahOi0qOmHj+WIhuaVsOOAgjwvcD4=
正确答案：QQ==
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
5/5单选题
难度：
5.传统“陈醋”生产过程中有一步称为“冬捞夏晒”，是指冬天捞出醋中的冰，夏日曝晒蒸发醋中的水分，以提高醋的品质，假设用醋酸的质量分数为3%的半成醋，生产500g 5.4%的优级醋，过程中醋酸没有损失，捞出的冰和蒸发的水的总质量为
| A | 500g |
| B | 400g |
| C | 200g |
| D | 100g |
- 提示1：
- IOWFiOaxguWHujMl55qE5Y2K5oiQ6YaL55qE6LSo6YeP
- 提示2：
- IOWGjeaxguWHuuaNnuWHuueahOWGsOWSjOiSuOWPkeeahOawtOeahOaAu+i0qOmHjw==
正确答案：Qg==
6Kej77ya6K6+MyXnmoTljYrmiJDphovnmoTotKjph4/kuLp477ybeMOXMyU9NTAwZ8OXNS40Je+8m3g9OTAwZzxicj7mjZ7lh7rnmoTlhrDlkozokrjlj5HnmoTmsLTnmoTmgLvotKjph489OTAwZy01MDBnPTQwMGc8YnI+5pWF6YCJQg==