Cho 7,8gam hỗn hợp A gồm metanol và etanol tác dụng với kali dư thu được 2,24 lít khí hidro ở đktc. Xác định thành phần phần trăm về khối lượng các chất trong hỗn hợp đầu ,tính khối lượng kali đã dùng và tính khối lượng muối thu được.

What is common about these molecules? a.their atoms are held together by covalent bonds. b.they are all made up of the same two atoms. c.their atoms are held together by ionic bonds. d.they are all made up of oxygen atoms only.

The diagram below shows a cell placed in a solution.a cell is shown placed inside a beaker. it is labeled cell. the solution inside the beaker is labeled 40% salt solution and the solution inside the cell is labeled 20% salt solution.only water is allowed to move in and out of the cell. what will most likely happen to the cell? it will expand as water moves out of it. it will shrink as water moves out of it.it will expand as water moves into it. it will shrink as water moves into it.

At stp, which substance is the best conductor of electricity? a. nitrogen b. neon c. sulfur d. silver