Answer:
only thing close I can see would be aluminun
Explanation:
atomic number of 13 and 8 2nd electrons in its shell.
B. 0.72 mol NaCl
http://www.convertunits.com/from/grams+NaCl/to/moles
Chemical equilibrium is reach when the concentrations of the product and reactants will no longer change with time. this does not mean that there is no change in concentration, only the net change is zero. the forward rate of reaction is now equal to backward rate of reaction.
Given, half life of a certain radioactive element = 800 years.
Amount of substance remaining at time t = 12.5%
Lets consider the initial amount of the radioactive substance = 100%
Using the half life equation:
A = A₀(1/2)^t/t₁/₂
where A₀ is the amount of radioactive substance at time zero and A is the amount of radioactive substance at time t, and t₁/₂ is the half-life of the radioactive substance.
Plugging the given data into the half life equation we have,
12.5 = 100 . (1/2)^t/800
12.5/100 = (1/2)^t/800
0.125 = (0.5)^t/800
(0.5)^3 = (0.5)^t/800
3 = t/800
t = 2400 years
Thus the object is 2400 years old.
5.5 grams of reactants. According to the Law of Conservation of Mass, mass isn’t created or lost through any chemical changes, so the total mass should remain constant from the initial reactants to the final products.
