Caffeine is 49.47% carbon, 5.19% H, 28.8%N
and 16.48% O. What is mass of carbon in 37.1g of caffeine?
37.1 g caffeine x 0.4947 = ? g C.
To calculate the mass of carbon in caffeine, we need to find the amount of carbon in a 37.1g sample of caffeine.
Step 1: Convert the percentages to mass.
The percentages given in the question represent the mass percent composition of each element. To convert these percentages to mass, we need to assume a total mass of 100g.
Mass of carbon = 49.47% of 100g = 49.47g
Mass of hydrogen (H) = 5.19% of 100g = 5.19g
Mass of nitrogen (N) = 28.8% of 100g = 28.8g
Mass of oxygen (O) = 16.48% of 100g = 16.48g
Step 2: Calculate the molar mass of caffeine.
The molar mass of caffeine (C8H10N4O2) can be calculated by summing the atomic masses of each element.
Molar mass of C = 12.01 g/mol
Molar mass of H = 1.01 g/mol
Molar mass of N = 14.01 g/mol
Molar mass of O = 16.00 g/mol
Molar mass of caffeine = (8 * Molar mass of C) + (10 * Molar mass of H) + (4 * Molar mass of N) + (2 * Molar mass of O)
Step 3: Find the moles of carbon in a 37.1g sample of caffeine.
Use the molar mass of caffeine to convert the mass of carbon to moles.
Moles of carbon = Mass of carbon / Molar mass of carbon
Step 4: Calculate the mass of carbon in the 37.1g sample of caffeine.
Mass of carbon in the 37.1g sample = Moles of carbon * Molar mass of carbon
By following these steps:
1. Convert the percentages to mass:
Mass of carbon = 49.47g
2. Calculate the molar mass of caffeine:
Molar mass of caffeine = (8 * 12.01 g/mol) + (10 * 1.01 g/mol) + (4 * 14.01 g/mol) + (2 * 16.00 g/mol) = 194.19 g/mol
3. Find the moles of carbon in a 37.1g sample of caffeine:
Moles of carbon = 49.47g / 194.19 g/mol = 0.25447 mol
4. Calculate the mass of carbon in the 37.1g sample of caffeine:
Mass of carbon in the 37.1g sample = 0.25447 mol * 12.01 g/mol = 3.06g
Therefore, the mass of carbon in a 37.1g sample of caffeine is approximately 3.06 grams.