bài 1 các chất và ion cho dưới đây đóng vai trò axit, bazơ, lưỡng tính hay trung tính ? tại sao ? nh4+, al(h20)3+, s2-, zn(oh)2, na+, cl-, so42-, no3- , co32- hòa tan các muỗi nacl, nh4cl, alcl3, na2s, kno3, na2co3 vào nước thành 6 dung dịch, sau đó cho vào mỗi dung dịch một ít quỳ tím. hỏi dung dịch có màu gì? tại sao?

Electromagnets coils of wire paper clips picked up 10 3 15 6 20 9 25 12 ms. owens' class was studying magnets. ms. owens showed her students how to make an electromagnet using a nail, a d-cell battery, and plastic coated wire. the students wrapped the wire around the nail and then attached the ends to the battery. when they were finished, they tested their magnets by investigating how many paperclips their magnets could pick up. they also tested whether they could increase the strength of their electromagnets by using more coils of wire. they recorded the class average of their results in the data table seen here. ms. owens asked her students to graph their data in a line graph. how should the students label the x-axis on their line graph? a) size of battery b) number of paper clips c) number of coils of wire d) strength of electromagnet