Polietilen được trùng hợp từ etilen. Hỏi từ 280g polietilen đã được trùng hợp từ bao nhiêu phân tử etilen, biết hiệu suất phản ứng trùng hợp là 50%?
A. $ {{5.6,02.10}^{23}} $
B. $ {{15.6,02.10}^{23}} $
C. $ {{20.6,02.10}^{23}} $
D. $ {{6,02.10}^{24}} $

Sản phẩm chính của phản ứng cộng giữa propen và HCl là
A.\(C{H_2} = CCl - C{H_3}\).
B.\(C{H_2} = CH - C{H_2}Cl\).
C.\(C{H_3} - CHCl - C{H_3}\).
D.\(C{H_2}Cl - C{H_2} - C{H_3}\).

Trong phân tử propen có số liên kết xích ma là
A.7
B.9
C.8
D.6

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
You must get home before __________. Otherwise, you won’t be allowed to go out for a long time in the future.
A.deal
B.law
C.curfew
D.rule

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
We don't have a/an __________ supply of money, you know. You need to spend it more wisely.
A.ending
B.endless
C.durable
D.lasting

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
The major factor causing the generation gap is the lack of _______ between parents and their children.
A.view
B.communication
C.contact
D.seeing

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Jenny lives in a/an _______ which consists of four generations.
A.extended family
B.nuclear family
C.family member
D.generation gap

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
_______ are the rules of behavior that are typically accepted while people are eating at a table.
A.table manners
B.social rules
C.viewpoints
D.footsteps

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
A(n) _______ is a big family that includes not only the parents and children, but also grandparents, uncles, aunts and cousins, all living under the same roof.
A.generation gap
B.extended family
C.nuclear family
D.family member

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
The decision was __________ by environmental groups for its harmful effects.
A.supported
B.criticized
C.approved
D.protected