Describe how you would make up3.2 g of a 5.00% aqueous solution of NaCl(i.e. find masses of the components that need to be mixed).
To make a 5.00% aqueous solution of NaCl weighing 3.2 g, we need to calculate the mass of NaCl and water needed. Here's how you can do it:
Step 1: Convert the percent concentration to a decimal fraction.
The concentration of the solution is given as 5.00%. To convert this to a decimal fraction, divide it by 100: 5.00% = 0.0500.
Step 2: Calculate the mass of NaCl required.
Multiply the mass of the solution (3.2 g) by the concentration fraction calculated in step 1:
Mass of NaCl = Mass of solution × concentration fraction
= 3.2 g × 0.0500
= 0.16 g
Therefore, you need 0.16 g of NaCl.
Step 3: Calculate the mass of water required.
To find the mass of water needed, subtract the mass of NaCl from the total mass of the solution:
Mass of water = Mass of solution - Mass of NaCl
= 3.2 g - 0.16 g
= 3.04 g
Therefore, you need 3.04 g of water.
Step 4: Combine the calculated masses.
Mix 0.16 g of NaCl with 3.04 g of water to prepare a 5.00% aqueous solution of NaCl weighing 3.2 g.
Note: It is important to ensure that the NaCl is completely dissolved in the water to obtain a homogeneous solution.