Answer: Scientists are working on nuclear fusion process. Nuclear fusion is the process in which two atomic nuclei combine to form another nuclei. In the process either energy is absorbed or released due to the difference in the mass of reactants and products.
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:
Aquatic plants have aur filled tissues to make them easy to float.....
Explanation:
It provides buoyancy
A combustion reaction is a reaction that reacts in the presence of oxygen molecules. Methane will release -3115 kJ/mol of heat.
<h3>What is a combustion reaction?</h3>
A combustion reaction includes the reaction between the chemical reactant and oxygen molecule to produce the product. The combustion reaction between methane and oxygen is given as:
CH₄(g) + 2O₂ (g) → CO₂(g) + 2H₂O (l), ΔH = -890 kJ/mol
The stoichiometry coefficient from the reaction gives 1 mole of methane releases -890 kJ/mol enthalpy.
So, 3.5 moles methane will release = 3.5 × -890 = -3115 kJ/mol
Therefore, -3115 kJ/mol of heat is released.
Learn more about combustion reaction here:
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