What is the % carbon by weight in 1.7 grams of potassium carbonate (K2CO3)? Answer in units of %.

%C = (atomic mass C/molar mass K2CO3) and change that to %.

To find the percent of carbon by weight in potassium carbonate (K2CO3), we first need to determine the molar mass of the compound.

The molar mass of potassium (K) is 39.10 g/mol, the molar mass of carbon (C) is 12.01 g/mol, and the molar mass of oxygen (O) is 16.00 g/mol.

To calculate the molar mass of potassium carbonate (K2CO3), we can add up the molar masses of each element present:
Molar mass of K2CO3 = (2 * molar mass of K) + molar mass of C + (3 * molar mass of O)

Molar mass of K2CO3 = (2 * 39.10) + 12.01 + (3 * 16.00)

Molar mass of K2CO3 = 78.20 + 12.01 + 48.00

Molar mass of K2CO3 = 138.21 g/mol

Now, to find the percent of carbon by weight, we divide the molar mass of carbon (12.01 g/mol) by the molar mass of potassium carbonate (138.21 g/mol) and multiply by 100 to get the percentage:

% Carbon by weight = (molar mass of C / molar mass of K2CO3) * 100

% Carbon by weight = (12.01 / 138.21) * 100

% Carbon by weight = 0.0868 * 100

% Carbon by weight ≈ 8.68%

Therefore, the percent carbon by weight in 1.7 grams of potassium carbonate (K2CO3) is approximately 8.68%.