Answer: (E) 300 bq
Explanation:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
Radioactive decay process is a type of process in which a less stable nuclei decomposes to a stable nuclei by releasing some radiations or particles like alpha, beta particles or gamma-radiations. The radioactive decay follows first order kinetics.
Half life is represented by 
Half life of Thallium-208 = 3.053 min
Thus after 9 minutes , three half lives will be passed, after ist half life, the activity would be reduced to half of original i.e. 
, after second half life, the activity would be reduced to half of 1200 i.e. 
, and after third half life, the activity would be reduced to half of 600 i.e. 
,
Thus the activity 9 minutes later is 300 bq.
One molecule of ammonia is composed of two atoms of nitrogen and three atoms of hydrogen. Option B.
<h3>What is an equation?</h3>
The term chemical equation has to do with the presentation of a chemical reaction on paper in a way that it can be easily understood. It is easy to write an equation to show what is going on in a reaction system.
Now we have the reactions as shown in the question. In this reaction which is the synthesis of ammonia and occurs industrially in the Haber process. The statement that is not true is that; one molecule of ammonia is composed of two atoms of nitrogen and three atoms of hydrogen. Option B.
Learn more about chemical equation:brainly.com/question/28294176
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Place the mixture in hot water and stir well.
<span>The KNO3 is very soluble in hot water. </span>
<span>Use a fine filter paper and filter off the sand. </span>
<span>The sand will be separated from the KNO3 solution. </span>
<span>The water can now be evaporated from the solution by further, gentle heating leaving the solid in the container.</span>
The shells further away from the nucleus are LARGER and can hold MORE electrons
Answer:
The lowest whole number mass ratio of nitrogen that combines with a given mass of oxygen is 1:1
Explanation:
In compound A, we have 14 g of nitrogen combine with 16 g of oxygen
In compound B, we have 14 g of nitrogen combine with 32 g of oxygen
Therefore, we have
A B
Ratio of molar masses 14:16 14:32
Mass of O that combine with 1 g of N 1.14 2.29
Dividing by the smallest mass ratio 1 2
Therefore the lowest whole number mass ratio at which oxygen and nitrogen can combine = 1:1.
