5 The apparatus shown below was set up. from cloth stopper
white cloud
glass tube

cotton wool soaked
in concentrated
hydrochloric acid
cotton wool soaked
in concentrated
ammonia solution
Give explanations for the following observations.

a The formation of a white cloud.

b It took a few minutes before the white cloud
formed.

c The white cloud formed further from the cotton
wool soaked in ammonia.

d Cooling the concentrated ammonia andhydrochloric acid before carrying out the
experiment increased the time taken for the
white cloud to form.

The rigid beam is supported by the three suspender bars. bars ab and ef are made of aluminum and bar cd is made of steel. if each bar has a cross-sectional area of 450 mm2, determine the maximum value of p if the allowable stress is (σallow)st = 200 mpa for the steel and ( σallow)al = 150 mpa for the aluminum. est = 200 gpa and eal = 70 gpa.

Imagine you work as a consultant, and your daily job involves listening to the constructive criticism of others. as part of your job, you must listen to opposing viewpoints to make important decisions. in this activity, you are a consulting dam engineer. you must make a decision about four different dams; should they be repaired, taken down, or left alone? you will listen to contrasting opinions about what should be done with the dams before you make the final decision. as the consulting dam engineer, what do you decide to do with this dam? explain your reasoning. by making your decision, did you support the opinions of the mayor and/or the dam safety official? why or why not? (site 1)

Drag each item into the proper state of matter category.