The general equation for radioactive decay is;
N = N₀e^(-λt)
x - decay constant (λ) - rate of decay
t- time
N - amount remaining after t days , since we are calculating the half life, amount of time it takes for the substance to to be half its original value, its N₀/2
N₀ - amount initially present
substituting the values
N₀/2 = N₀e^(-0.081t)
0.5 = e^(-0.081t)
ln (0.5) = -0.081t
-0.693 = -0.081t
t = 0.693 / 0.081
= 8.55
half life of substance is 8.55 days
Answer:
1.59 x 10⁻²⁵ J.
Explanation:
- The energy of a photon is calculated Planck - Einstein's equation:
E = h ν
, where
E is the energy of the photon,
h is Planck's constant <em>(h = 6.626 x 10
⁻³⁴ J.s)</em>
ν is the frequency of the photon
-
There is a relation between the frequency (ν
) and wave length (λ).
λ.ν = c,
where c is the speed of light in vacuum (c = 3
.0 x 10
⁸ m/s).
λ = 125 cm = 1.25 m.
<em>Now, E = h.c/λ.</em>
∴ E = h.c/λ = (6.626 x 10
⁻³⁴ J.s) (3
.0 x 10
⁸ m/s) / (1.25 m) = 1.59 x 10⁻²⁵ J.
<u>Answer:</u> The correct answer is Option A.
<u>Explanation:</u>
Mole ratio is defined as the ratio between the stoichiometric coefficients of the molecules present in the chemical reaction.
For the given balanced chemical equation:
By Stoichiometry of the reaction:
3 moles of iron metal reacts with 4 moles of water to produce 1 mole of iron oxide and 4 moles of hydrogen gas.
The mole ratio of 
Hence, the correct answer is Option A.
Answer:
Explanation:
Hello,
In this case, during titration at the equivalence point, we find that the moles of the base equals the moles of the acid:
That it terms of molarities and volumes we have:
Next, solving for the volume of lithium hydroxide we obtain:
Best regards.
Answer:
Explanation:
You are not really helped by what is hold the liquid. Beakers and cylinders come on a lot of sizes. I hate to be crabby about things like that, but you really need to be aware that the question is slightly flawed (not your fault).
The beaker, you'd be like to get 1 sig digit. You have to be awfully careful about claiming more. So the and is 50 mL, but that mL is a guess and the 50 is not totally accurate, but what would you say the second digit is? 48 or 47? You don't really know. Maybe even 49.
The graduated cylinder is a little better. Read the bottom of the meniscus (the bottom of the 1/2 bubble). I think you can get 2 sig digs., so the answer is 36 mL. But everything also depends on what you have been told.
