The mass decay rate is of the form

where
m₀ = 3000 g,the initial mass
k = the decay constant
t = time, years.
Because the half-life is 30 years, therefore

After 60 years, the mass remaining is

Answer: 750 g
O = C = O Straight because there is no solitary electrons on C
Answer:
B
Explanation:
cool air never rises so not A
C would mean its getting warmer
and heat flows from warm to cool so not D
we are left with B
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Answer:
The state of matter of rain is liquid. Clouds are 2 states of matter, liquid and gas
Explanation:
Answer: The correct option is 2.
Explanation: Polyatomic ions are defined as the ions in which two or more elements are covalently bonded to act as a single unit. They always carry some charge.
Examples of polyatomic ions are:
known as hydroxide ion,
known as sulfate ion
We are given a compound
having 2 ions which are
and
. these ions are named as sodium ions and hydrogen carbonate ions.
Therefore, the correct option is 2.