The age of the fossil given the present amount of Carbon-14 is given in the equation,
A(t) = A(o)(0.5)^t/h
where A(t) is the current amount, A(o) is the initial amount, t is time and h is the half-life. Substituting the known values to the equation,
A(t) / A(o) = 0.125 = (0.5)^(t/5730)
The value of t from the equation is 17190.
Thus, the age of the fossil is mostly likely to be 17190 years old.
<span>Answer: D. They all have the same number of electrons in the electron cloud</span>
Answer:
Kb = 6.22x10⁻⁷
Explanation:
Triethanolamine, C₆H₁₅O₃N, is in equilibrium with water:
C₆H₁₅O₃N(aq) + H₂O(l) ⇄ C₆H₁₅O₃NH⁺(aq) + OH⁻(aq)
Kb is defined from concentrations in equilibrium, thus:
Kb = [C₆H₁₅O₃NH⁺] [OH⁻] / [C₆H₁₅O₃N]
The equilibrium concentration of these compounds could be written as:
[C₆H₁₅O₃N] = 0.486M - X
[C₆H₁₅O₃NH⁺] = X
[OH⁻] = X
pH is -log [H⁺], thus, [H⁺] = 10^-pH = 1.820x10⁻¹¹M
Also, Kw = [OH⁻] ₓ [H⁺];
1x10⁻¹⁴ = [OH⁻] ₓ [H⁺]
1x10⁻¹⁴ = [OH⁻] ₓ [1.820x10⁻¹¹M]
5.495x10⁻⁴M = [OH⁻], that means <em>X = 5.495x10⁻⁴M</em>
Replacing in Kb formula:
Kb = [5.495x10⁻⁴M] [5.495x10⁻⁴M] / [0.486M-5.495x10⁻⁴M]
<em>Kb = 6.22x10⁻⁷</em>
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Answer:
Explanation
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One
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Ca(OH)2 + 2HNO3 -----> Ca(NO3)2 + H2O
Focus on the NO3. This is an odd problem and you usually do not focus on the complex ion. But this one works easiest if you do.
The problem now is going to be the oxygens. There are 2 with the Calcium and only 1 free one going to the water. (The NO3 has been taken care of in the last step).
Ca(OH)2 + 2HNO3 -----> Ca(NO3)2 + 2H2O
Count the atoms. I think this equation is balanced.
atom Left Right Result
Ca 1 1 Balanced
O 8 8 Balanced
H 2 + 2 2*2 Balanced
N 2 2 Balanced
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Two
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CH4 + O2====> CO2 + H2O
Start with the hydrogens.
The right side requires a 2
CH4 + O2 ===> CO2 + 2H2O
Now look at the oxygens. There are 4 on the right. and only 2 on the left. You need to multiply O2 by 2
CH4 + 2O2 ===> CO2 + 2H2O
Each side has 1 Carbon 4 hydrogens and 4 oxygens. The equation is balanced.
Answer:
All the noble gases have the full number of electrons in each layer.
Explanation:
For example, neon is a noble gas. The first layer of electrons is full since it contains the max amount of electrons which is 2. The next layer is also full, since it contains 8 electrons which is the max amount it can hold.
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