Answer:
0.60 moles of atoms of carbon
Explanation:
Step 1: Given data
- Chemical formula of the compound: Mg(HCO₃)₂
- Moles of oxygen atoms: 1.8 moles
Step 2: Calculate the number of carbon atoms in the given sample
According to the chemical formula of the compound, the molar ratio of C to O is 2:6, that is, there are 2 moles of atoms of C every 6 moles of atoms of O. The number of moles of atoms of C is:
1.8 mol O × 2 mol C / 6 mol O = 0.60 mol C
First let us calculate for the rate constant k from the
formula:
k = ln(2) / t0.5
where t0.5 is the half life
k = ln(2) / 1.3x10^9 years
k = 5.33x10^-10 years-1
Then we use the formula:
A/Ao = e^-kt
where A/Ao is the amount remaining = 25% = 0.25, t is
time
Rearranging to get t:
t = ln(A/Ao) / -k
t = ln(0.25) / (-5.33x10^-10 years-1)
t = 2.6x10^9 years
Answer: For number 8. I think only one if not i'm so sorry also you would need 143. 0914
Explanation:
<span>Heavy metals like mercury enter waterways by industrial dumping and poor regulatioin of effluent, and they also enter soil through a similar manner, in which waste is disposed of imporperly. Another source of heavy metals are the gases leaving industry carrying these metals. The metals fall as a solid on to soil and water ways. Therefore, the answer is D.</span>
