What is the mass of Na2CO3 required to make a 500 mL standard solution of 0.400 mol/L Na2CO3?
a. 212 g
b. 23.4 g
c. 25.8 g
d. 27.39

21.2 g

Explanation:

Step 1: Given data

Step 2: Calculate the moles of Na₂CO₃ (solute) in the solution

We will use the definition of molarity.

C = moles of solute / liters of solution

moles of solute = C × liters of solution

moles of solute = 0.400 mol/L × 0.500 L = 0.200 mol

Step 3: Calculate the mass corresponding to 0.200 moles of Na₂CO₃

The molar mass of Na₂CO₃ is 105.99 g/mol.

0.200 mol × 105.99 g/mol = 21.2 g

the dependant variable is spilled water

the independent is the heat