D. is the missing element.
Carlos <em>hasn’t done research</em> on what other scientists have observed and investigated on this topic. If he hasn’t done his literature research, he may just be repeating the experiments of other scientists working in the same area.
Options “A.”, “B.”, and “C.” are all part of the scientific method.
Measuring cylinder, Pipette, Burette ( most accurate volume ).
The correct option would be A.
Hope this helps!! (:
Answer:
If you want the first option you need 2.5M.
If you want the second, you will end up with 120ml so your starting solution is:
0.5x (120/20) = 3.0M
This assumes that there’s no loss of volume on mixing. To remove that uncertainty, start with the 20ml of acid and add water, mixing, till you get the right volume.