The Cell Membrane.
The Cell Membrane wraps around the entire cell and only allows certain things to pass through, blocking out potentially harmful things from the organelles within the cell.
Hope this helps!
Answer : The partial pressure of helium is, 
Solution : Given,
Molar mass of 
= 32 g/mole
Molar mass of helium = 4 g/mole
Molar mass of 
= 28 g/mole
Total pressure of gas = 
As we are given gases in percent, that means 10 g of oxygen gas, 50 g of helium gas and 40 g of nitrogen gas present in 100 g of mixture.
First we have to calculate the moles of oxygen, helium and nitrogen gas.
Now we have to calculate the total number of moles of gas mixture.
Now we have to calculate the moles fraction of helium gas.
Now we have to calculate the partial pressure of helium.
where,
= partial pressure of helium
= total pressure
= mole fraction of helium
Now put all the given values in this formula, we get
Therefore, the partial pressure of helium is,
<span>To find the molar mass, look at a periodic table for each element.
Ibuprofen, C13 H18 and O2. Carbon has a molar mass of 12.01 g, Hydrogen has 1.008 g per mole, and Oxygen is 16.00 g per mole.
C: 13 * 12.01
H: 18 * 1.008
O: 2 * 16.00
Calculate that, add them all together, and that is the molar mass of C13H18O2.
Molar mass: 206.274
Next, you have 200mg in each tablet, with a ratio of C13H18O2 (molar mass) in GRAMS per Mole
So, you need to convert miligrams into grams, which is 200 divided by 1000.
0.2 g / Unknown mole = 206.274 g / 1 Mole
This is a cross multiplying ratio where you're going to solve for the unknown moles of grams per tablet compared to the moles per ibuprofen.
So, it's set up as:
0.2 g * 1 mole = 206.274 * x
0.2 = 206.274x
divide each side by 206.274 to get X alone
X = 0.00097
or 9.7 * 10^-4 moles
The last problem should be easy to figure out now that you have the numbers. 1 dose is 2 tablets, which is the moles we just calculated above, times four for the dosage.
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