which is the formula mass of na2so4? 119.06 amu 125.98 amu 142.05 amu 174.12 amu

Explanation:

Step1: Find atomic masses

The atomic mass of Na (sodium) is approximately 22.99 amu, S (sulfur) is approximately 32.07 amu, and O (oxygen) is approximately 16.00 amu.

Step2: Calculate mass of sodium in formula

In $Na_2SO_4$, there are 2 Na atoms. So mass of Na is $2\times22.99 = 45.98$ amu.

Step3: Calculate mass of sulfur in formula

There is 1 S atom. So mass of S is 32.07 amu.

Step4: Calculate mass of oxygen in formula

There are 4 O atoms. So mass of O is $4\times16.00=64.00$ amu.

Step5: Calculate formula - mass

Formula - mass of $Na_2SO_4$ is $45.98 + 32.07+64.00 = 142.05$ amu.

Answer:

142.05 amu