Answer:
5 mg
Explanation:
If one half life is 4 hours, then 3 half lives is 12 hours.
This means that the sample will decay to 1/8 of its original amount.
So, the answer is 40(1/8) = 5 mg.
Molarity = Moles/Liter
Use the molecular atomic mass of NaCl to convert from grams to moles.
Molecular mass of NaCl is the sum of its atomic masses. Look at the periodic table to find these. Na is 23 g/mol and Cl is 35.5 g/mol ,
so NaCl = 23 + 35.5 = 58.5 g/mol
multiply to cancel out grams
76 g NaCl * (1mol / 58.5 g NaCl) = 1.3 mol NaCl
over 1 Liter is just 1.3 M NaCl
Hope this helps!
Answer:
B
Explanation:
it is bigger then earth so it will have a greater mass.
Answer:
Total pressure 5.875 atm
Explanation:
The equation for above decomposition is

rate constant 
Half life 
Initial pressure 
Pressure after 3572 min = P
According to first order kinematics


solving for P we get
P = 2.35 atm

initial 4.70 0 0
change -2x +2x +x
final 4.70 -2x 2x x
pressure of
after first half life = 2.35 = 4.70 - 2x
x = 1.175
pressure of
after first half life = 2x = 2(1.175) = 2.35 ATM
Total pressure = 2.35 + 2.35 + 1.175
= 5.875 atm