Question

HELP ASAP

Answer 1

Answer:

1) 206 g /mol

2) 0.971 mmol or 9.71 X 10⁻⁴ mol

3) 7.768 mmol or 7.768 X 10⁻³ mol

Explanation:

1) Let us calculate the molar mass by adding the atomic mass of each atom present in the given ibuprofen molecule.

Molecular formula : C₁₃H₁₈O₂

Molar mass = 13 X atomic mass of C + 18X atomic mass of H +2 X atomic mass of O

Molar mass = 13 X 12 + 18X1 + 2X16 = 206g/mol

2) moles is calculated as:

$moles=\frac{mass}{molarmass}=\frac{200mg}{206}=0.971mmol$

This is the moles in each ibuprofen tablet.

3) Now in each dose there are two tablets.

The adult took four doses

The number of tablets taken = 4X2 = 8

the number of moles taken = 8X0.971 mmol = 7.768 mmol

Answer 2

 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.