Chemical change, because the white powder heated the water and caused a thermal reaction, and possibly gas was produced due to bubbles.
Nh4cl (the oxidation number of N=-3) so it would be the right answer
I believe that the answer to the question provided above is that molecules in solid are compact and are connected. It requires huge energy to move it, thus requires high temperature.
Hope my answer would be a great help for you. If you have more questions feel free to ask here at Brainly.
Once the torch is lit, the acetylene flow must be increased until the flame stops smoking <span>before the oxygen is turned on for adjustment in order to keep the tip of the torch cool.
You should also note that while lighting the torch, you should keep the spark lighter near the tip but not covering it.</span>