8 seconds have passed. There is a sample of lithium-8 being tested. The half-life of lithium-8 is 0.84 seconds. The sample of lithium-8 after 8 seconds is 28 grams. How much lithium-8 was in the sample at the beginning of the experiment? Round your answer to 2 sig figs.
Do no forget units!

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm

the answer would be c

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l