Answer:
atomic, neutrons
Explanation:
the mass number of an atom is equal to the sum of the protons and neutrons in the nucleus of the atom.
Answer:
you need to send us the figure
Explanation:
Half-life of a radioactive substance is the time required to reduce the amount of substance to half of its initial amount.
In present case, half-life is material is given as 1000 years and initial amount of material is given as 400 kg
Answer 1) Since, half-life of radio-active substance is 1000 years, therefore after 1st half life, amount of the material will be left to half the initial amount. Hence, amount of substance left after 1000 years = 400/2 = 200 kg.
Answer 2) For 2000 years, radioactive material has crossed 2 times the half life. Therefore , amount of the material will be left to 1/4 the initial amount. Hence, amount of substance left after 2000 years = 400/4 = 100 kg.
Answer 3) For 4000 years, radioactive material has crossed 4 times the half life. Therefore , amount of the material will be left to 1/16 the initial amount. Hence, amount of substance left after 4000 years = 400/16 = 25 kg.
Answer : The time passed in days is 28.6 days.
Explanation :
Half-life = 14.3 days
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant =
t = time passed by the sample = ?
a = let initial amount of the reactant = 100 g
a - x = amount left after decay process = 100 - 75.0 = 25.0 g
Now put all the given values in above equation, we get
Therefore, the time passed in days is 28.6 days.