This plateau is where a phase change occurs. Likely, this cooling curve observes the changing of a liquid into a solid (so that the temperature is quantifiable). As something cools, it’s losing energy to the surroundings; when a phase change occurs, like liquid to solid, energy isn’t lost directly from the atom, but instead the energy maintained by free motion of the atom is used. This lack of motion reduces it into a lattice (all while maintaining a constant internal energy), finalizing the phase change, after which energy is lost directly from the atom again.
<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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<span>Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles. We calculate as follows:
0.340 mol Br2 ( </span>6.022 x 10^23 molecules / mol ) = 2.05 x 10^23 molecules
Answer:
Explanation:
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is ²³Na. The free metal does not occur in nature, and must be prepared from compounds.
