A. The radioactive decay equation is N = N0
where T is the
half-life (5730 years), N0 is the number of atoms at time t = 0 and
N is the number at time t.
Rewriting this as:
(N/N0) = 
Since N = (1/8) N0 and
substituting known values:
1/8 = 
Taking ln of both
sides:
ln(1/8)= -ln(2)*t/5730
t = - 5730 * ln(1/8) /
ln (2)
t = 17,190 years
The tree was cut down 17,190
years ago.
B. N0 = 1,500,000 carbon-14 atoms
Since N = (1/8) N0
N = 187,500 carbon
atoms left
Answer:
mL of NaOH required =29.9mL
Explanation:
Let us calculate the moles of vitamin C in the tablet:
The molar mass of Vitamin C is 176.14 g/mole

Thus we need same number of moles of NaOH to reach the equivalence point.
For NaOH solution:



Answer:
The 12L helium tank pressurized to 160 atm will fill <em>636 </em>3-liter balloons
Explanation:
It is possible to answer this question using Boyle's law:

Where P₁ is the pressure of the tank (160atm), V₁ is the volume of the tank (12L), P₂ is the pressure of the balloons (1atm, atmospheric pressure) And V₂ is the volume this gas will occupy at 1 atm, thus:
160atm×12L = 1atm×V₂
V₂ = 1920L
As the tank will never be empty, the volume of the gas able to fill balloons is the total volume minus 12L, thus the volume of helium able to fill balloons is:
1920L - 12L = 1908L
1908L will fill:
1908L×
= <em>636 balloons</em>
<em></em>
I hope it helps!
Answer:

Explanation:
Percent yield is the ratio of the amount actually produced to how much could theoretically be produced. It is found using this formula:

For this reaction, the theoretical or expected yield is 325.0 grams. The actual yield is 123.8 grams.

Divide.


Round to the nearest hundredth. The 9 in the hundredth place tells us to round the 0 to a 1 .

The percent yield is about <u>38.1%</u>