5 moles because molarity signifies number of moles dissolved in One litre of water
Speed=distance/time
D=150km
S=7200s
Divide the numbers.
150/7200=0.02km/s <---final answer
Answer:
The right answer is "3 g".
Explanation:
Given:
Initial mass substance,

By using the relation between half lives and amount of substances will be:
⇒ 


Thus, the above is the correct answer.