Calculate the formula unit mass of  K2CO3 Select an answerA81 uB62 uC138 uD26 u

To calculate the formula unit mass of K2CO3, you need to know the atomic masses of potassium (K), carbon (C), and oxygen (O).

1. The atomic mass of potassium (K) is approximately 39.1 u. Since there are 2 potassium atoms in K2CO3, the total mass contributed by potassium is 39.1 u * 2 = 78.2 u.

2. The atomic mass of carbon (C) is approximately 12.01 u. Since there is 1 carbon atom in K2CO3, the total mass contributed by carbon is 12.01 u * 1 = 12.01 u.

3. The atomic mass of oxygen (O) is approximately 16.00 u. Since there are 3 oxygen atoms in K2CO3, the total mass contributed by oxygen is 16.00 u * 3 = 48.00 u.

4. Add up the masses contributed by potassium, carbon, and oxygen to get the formula unit mass of K2CO3: 78.2 u + 12.01 u + 48.00 u = 138.21 u.

So, the formula unit mass of K2CO3 is approximately 138 u. Therefore, the correct answer is C138 u.