Students watched a cartoon either alone or with others and then rated how funny they found the cartoon to be. What is the indepe
2 answers:
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Answer:
20619.4793 years
Explanation:
The half life of carbon-14 = 5730 years
The formula for the half life for a first order kinetic reaction is:
Where,
is the half life
k is the rate constant.
Thus rate constant is:
5730 years=ln(2)/k
k = 1.21×10⁻⁴ years ⁻¹
Using integrated rate law as:
Where,
is the concentration at time t
is the initial concentration
Given that the final concentration contains 8.25 % of the original quantity which means that:
So,
ln(.0825)= -1.21×10⁻⁴×t
<u> t = 20619.4793 years</u>
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Answer:
Explanation:
We are given the percent composition: 22.5% phosphorus and 77.5% chlorine.
We can assume there are 100 grams of this compound. We choose 100 because we can simply use the percentages as the masses.
- 22.5 g P
- 77.5 g Cl
Next, convert these masses to moles, using the molar masses found on the Periodic Table.
- P: 30.974 g/mol
- Cl: 35.45 g/mol
Use the molar masses as ratios and multiply by the number of grams.
Divide both of the moles by the smallest number of moles to find the mole ratio.
The mole ratio is about 1 P: 3 Cl, so the empirical formula is written as:<u> PCl₃</u>