Answer:
Explanation:
count given by old sample = .97 disintegrations per minute per gram
count given by fresh sample = 6.68 disintegrations per minute per gram
Half life of radioactive carbon = 5568 years
rate of disintegration
dN / dt = λ N
In other words rate of disintegration is proportional to no of radioactive atoms present . As number reduces rate also reduces .
Let initial no of radioactive be N₀ and after time t , number reduces to N
N₀ / N = 6.68 / .97
Now



λ is disintegration constant
λ = .693 / half life
= .693 / 5568
= .00012446 year⁻¹
Putting the values in the equation above


1.929577 = .00012446 t
t = 15503.6 years .
Answer:
dipole-dipole
Explanation:
Polar molecules are formed as result of covalent bonds between atoms.
Dipole-dipole attraction are intermolecular bonds. Both London dispersion forces and dipole-dipole attraction are van der waals forces.
In dipole-dipole attraction, polar molecules (unsymmetrical molecules) line up such that the positive pole of one molecule attracts the negative pole of another. Example of such is found in HCl.
Answer:
pH = 4.4
Explanation:
pH = -log[H₃O⁺]
= -log(4.3 × 10⁻⁵)
pH = 4.37 = 4.4
I'm actually learning this in my chemistry class right now lol. Hope this helps though. :)
Answer:
Assuming that all of the oxygen is used up, 1.53×4111.53×411 or 0.556 moles of C2H3Br3 are required. Because there are only 0.286 moles of C2H3Br3 available, C2H3Br3 is the limiting reagent.
Limiting Reagent What is the limiting reagent if 76.4 grams of C2H3Br3 were reacted with 49.1 grams of O2? C2H3Br3 + 11O2 → 8CO2 + 6H2O + 6Br2 SOLUTION Using Approach 1: A. 76.4g × (1 mol/ 266.72 g) = 0.286 moles C2H3Br3 49.1g × (1 mole/ 32 g) = 1.53 moles O2 B.
Explanation:
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https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Map%3A_Introductory_Chemistry_(Tro)/08%3A_Quantities_in_Chemical_Reactions/8.04%3A_Limiting_Reactant_and_Theoretical_Yield
Answer: In order to melt a network solid, a relatively large amount of heat is needed, sufficient to break the covalent bonds that hold the entire solid together
hope this helps