B

PTHH: 2A + Cl2 --> 2ACl
Áp dụng ĐLBTKL:
m_A + m_{Cl2 pư} = m_ACl
--> m_{Cl2 pư} = m_ACl - m_A=29,25-11,5
                    = 17,75 (g)
--> n_Cl2 pư=17,75/71=0,25 (mol)
Theo PTHH, n_A = 2.n_{Cl2 pư} = 2.0,25 = 0,5 (mol)
--> M_A=11,5/0,5=23 (g/mol) --> A là Na --> CT của muối là NaCl 
Đáp án: C

Johnny told me he didn't know how to do that exercise.

A
C
C
B

B-->terrifying

ve hãy gọi mùa hè

=

227,5

 
=8,75.(2,15+9,34-1,49)
=8,75.10=87,5

30. He asked me if I was student.
31. I asked her if she studied at that school.
32. I asked him if there were many students at that school.
33. The tourists asked us if Phong Nha cave was in central Viet Nam.
34. I have learned English since 2005.
35. Nam asked if Lan liked reading poems.