Your answer should be D. About 4 years. Hope this helps! =^-^=
<em>(The light reflected from the surface of the Moon takes only a second to reach Earth. The Sun is more than 8 light-minutes away. And so, if the light from the nearest star (Alpha Centauri) takes more than 4 years to reach us, we're seeing that star 4 years in the past.) Quora.com</em>
Answer:
Option 4 is correct (72 seconds)
Explanation:
Option 4 is correct (72 seconds)
The formula we are going to use is:
Where:
A is the final concentration
A_o is the initial concentration
k is the constant
t is the time
Half-Life=0.693/k
Half-life in our case=24 seconds
k=0.693/24
k=0.028875 s^-1
Since the concentration is decreased by 87.5 % which means only 12.5%(100-87.5%) is left.
The ratio 
will become 0.125
t≅ 72 seconds
Answer:
Number of moles = 0.51 mol
Explanation:
Given data:
Mass of CO₂ = 22.4 g
Number of moles = ?
Solution:
Number of moles of CO₂:
Number of moles = mass/molar mass
Molar mass of CO₂ = 44 g/mol
by putting values,
Number of moles = 22.4 g/ 44 g/mol
Number of moles = 0.51 mol
