问题 选择题

(10成都12) 某食品干燥剂为白色固体,化学兴趣小组同学欲探究其成分,进行如下实验:

下列判断不正确的是(   )

A.称取2.0g干燥剂要用到的仪器是托盘天平

B.操作I是过滤

C.溶液a与溶液b可能都含有OH且具有相似的性质

D.该干燥剂的主要成分可能是生石灰,也可能是烧碱

答案

答案:D

A、此干燥剂为白色固体,称量时应该使用托盘天平,故A正确;

B、经过操作I,能得到沉淀a和溶液b,则该操作应该为过滤,故B正确;

C、常见的食品干燥剂是生石灰,能与水反应生成氢氧化钙,氢氧化钙能与碳酸钠反应生成氢氧化钠,所以溶液a与溶液b可能都含有OH-且具有相似的性质,故C正确;

D、烧碱具有极强的腐蚀性,不能用作食品干燥剂,故D错误,

故选D.

单项选择题
单项选择题

Phyllis Wheatley is regarded as America’’s first black poet. She was born in Senegal, Africa, about 1753 and brought to America aboard a slave ship at about the age of seven. John and Susannah Wheatley bought her for three pounds at a slave auction in Boston in 1761 to be a personal servant of Mrs. Wheatley. The family had three other slaves, and all were treated with respect. Phyllis was soon accepted as one of the family, which included being raised and educated with the Wheatley’’s twin 15-year-old children, Mary and Nathaniel. At that time, most females, even from better families, could not read and write, but Mary was probably one of the best educated young women in Boston. Mary wanted to become a teacher, and in fact, it was Mary who decided to take charge of Phyllis’’s education. Phyllis soon displayed her remarkable talents. At the age of twelve she was reading the Greek and Latin classics and passages from the Bible. And eventually, Mrs. Wheatley decided Phyllis should become a Christian.At the age of thirteen Phyllis wrote her first poem. She became a Boston sensation after she wrote a poem on the death of the evangelical preacher George Whitfield in 1770. It became common practice in Boston to have "Mrs. Wheatley’’s Phyllis" read poetry in polite society. Mary married in 1771, and Phyllis later moved to the country because of poor health, as a teacher and caretaker to a farmer’’s three children. Mary had tried to interest publishers in Phyllis’’s poems but once they heard she was a Negro they weren’’t interested.Then in 1773 Phyllis went with Nathaniel, who was now a businessman, to London. It was thought that a sea voyage might improve her health. Thirty-nine of her poems were published in London as Poems on Various Subjects, Religious and Moral. It was the first book published by a black American. In 1775 Phyllis wrote a poem extolling the accomplishments of George Washington and sent it to him. He responded by praising her talents and inviting her to visit his headquarters. After both of her benefactors died in 1777, and Mary died in 1778, Phyllis was freed as a slave. She married in 1778, moved away from Boston, and had three children. But after the unhappy marriage, she moved back to Boston, and died in poverty at the age of thirty.

Which of the following conclusions about Phyllis is supported by the passage

A.She would have been more recognized as a poet if she had not been black.

B.She would have written poetry if she had stayed in Africa.

C.She went unrecognized as a poet during her lifetime.

D.She only wrote religious poetry.