The atomic radius of main group elements generally increases down a group because as there are more electrons they are farther away from the nucleus and the electrons closer to the nucleus shield the outer electrons from the protons for attraction.
Answer: There are 0.000043 moles of melatonin.
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 
of particles.
To calculate the moles, we use the equation:
given mass = 10 mg = 0.01 g
molar mass of 
= 232.28 g
Thus there are 0.000043 moles of melatonin
The answer Is C.the layer of rock they're found in
Answer:
Cells are uncountable becasue they move around your body, make up your skin and other organs as well. And because when you grow, the cells multiply, and that makes it very hard for scientists to count cells in a human's body.
Explanation:
Hope this helped!
The given equation from the problem above is already balance,
N2O5 ---> 2NO2 + 0.5O2
Since, in every mole of N2O5 consumed, 2 moles of NO2 are formed, we can answer the problem by multiplying the given rate, 7.81 mol/L.s with the ratio.
(7.81 mol/L.s) x (2 moles NO2 formed/ 1 mole of N2O5 consumed)
= 15.62 mol/L.s
The answer is the rate of formation of NO2 is approximately 15.62 mol/L.s.
