Answer:
True!
Explanation:
Soap molecules form something called micelle. If you look it up, these are usually formed if something has a hydrophobic tails (water hating) and hydrophilic heads (water loving).
So essentially when you try to get the grease off of your shirt or hand, the soap hydrophobic ends interact with grease and capture it and the water interacts with the hydrophilic heads to pull the micelle out releasing the grease.
The formula for pOH is -log(M)
So, all we need to do is plug in that number! -log(4.5x10^-3)
That gives us 2.3, so the pOH is 2.3 :)
The combustion of ethane is expressed in the balanced reaction C2H6 + 3.5O2= 2CO2 + 3 H2O. Given the mass of oxygen gas, we get the moles of ethane needed by converting this mass to mole (dividing my 32 g/mol), then multiply by 1/3.5 (stioch ratio) and the molar mass of ethane (30 g/mol). The answer is 16.69 grams ethane.
Answer:
Explanation:
A radioactive isotope is an isotope that undergoes nuclear decay, breaking apart into a smaller nucleus and emitting radiation during the process.
The half-life of an isotope is the amount of time it takes for a certain quantity of a radioactive isotope to halve.
For a radioactive isotope, the amount of substance left after a certain time t is:
(1)
where
is the mass of the substance at time t = 0
m(t) is the mass of the substance at time t
is the half-life of the isotope
In this problem, the isotope is uranium-235, which has a half-life of
We also know that the amount of uranium left in the rock sample is 6.25% of its original value, this means that
Substituting into (1) and solving for t, we can find how much time has passed:
4.88x10^20 H2O2 molecules
