Answer:
= 72900 years
Explanation:
- The half-life is the time taken by a radioactive material to decay by half the original amount.
- The half-life of plutonium-239 is 24300 years which means it takes 24300 years to decay by half the original amount.
To calculate the time taken for a mass of 8 kg to decay to 1 kg we use;
New mass = Original mass x (1/2) ^n, where n is the number of half-lives
Therefore;
1 kg = 8 kg × (1/2)^n
1/8 = (1/2)^n
solving for n;
n =3
Therefore;
Time = 3 × 24300 years
= 72900 years
It will, therefore, take 72900 years for 8 kg of plutonium-239 to decay to 1 kg.
Answer:
see explanation
Explanation:
Write the balanced COMPLETE ionic equation for the reaction when Na₂CO₃ and AgNO₃ are mixed in aqueous solution. If no reaction occurs, simply write only NR.
Ag (+1) + NO3(-1) + 2 Na(+1) + Co3 (-2)--> Ag2CO3 (s) + 2 Na (+1) + 2NO3(-1)
It is softer than topaz and and it is softer than diamond (diamond has a Mohs hardness of 10, which is the highest value of the scale)
Answer: The ratio of carbon dioxide molecules to oxygen molecules is 20 :31
Explanation:
Combustion is a chemical reaction in which hydrocarbons are burnt in the presence of oxygen to give carbon dioxide and water.
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced combustion reaction is,:
Thus the ratio of carbon dioxide molecules to oxygen molecules is 20 : 31
