Because if you change two things then you do not know which one has affected or altered the dependent variable. if you only change one then you know what exactly changed and why
Answer:
Explanation:
exothermic reactions are the reactions which involve the release of energy.
the energy released can be of any forms ,for example heat,light .
all the combustion reactions are exothermic reactions
Answer:
56°
Explanation:
First calculate 

The interplanar spacing can be calculated from:

The diffraction angle is determined from:

Solve for 

The diffraction angle is:
