It is a Compound.
Water can't be a mixture because it is chemically bonded and cannot be separated into H2 and O by physical means.
And water cannot be an element, because it is made of atoms of different types [H and Oxygen]
A. and D. would be the best pick for this sort of experiment, but maybe (unlikely) B. because you could see how they could react in certain situations, how they react to danger but I suggest A.
Hope this helps you ☁︎☀︎☁︎
Answer:1 mol of Mg(NO3)2 contains 6.022*10^23 molecules
3 mol Mg(NO3)2 contains 3*6.022*10^23 = 1.81*10^24 molecules
Each Mg(NO3)2 molecule contains 2 N atoms
Number of N atoms = 2*1.81*10^24 = 3.62*10^24 N atoms.
Answer:
the Rhyniognatha hirsti
Explanation:
at age 400 million years old