A lab technician mixes a 0.730 M solution of sodium bromide (NaBr) and water. The volume of the solution is 135 milliliters.
What is the mass of dissolved sodium bromide in the solution?
anbaat -

We need 10.14 grams of sodium bromide to make a 0.730 M solution

Explanation:

Step 1: Data given

Molarity of the sodium bromide (NaBr) = 0.730 M

Volume of the sodium bromide solution = 135 mL = 0.135 L

Molar mass sodium bromide (NaBr) = 102.89 g/mol

Step 2: Calculate moles NaBr

Moles NaBr = Molarity NaBr * volume NaBr

Moles NaBr = 0.730 M * 0.135 L

Moles NaBr = 0.09855 moles

Step 3: Calculate mass of NaBr

Mass NaBr = 0.09855 moles * 102.89 g/mol

Mass NaBr = 10.14 grams

We need 10.14 grams of sodium bromide to make a 0.730 M solution

Explanation:

2HNO₃ + Ba( OH)₂ = Ba( NO₃ )₂ + 2H₂O .

2 mole      1 mole

13.9 mL of .174M barium hydroxide contains .0139 x .174 moles

= 2.42 x 10⁻³ moles .

1 mole of barium hydroxide reacts with 2 moles of nitric acid

2.42 x 10⁻³ moles of barium hydroxide will react with 2 x 2.42 x 10⁻³ moles of nitric acid

= 4.84 x 10⁻³ moles

4.84 x 10⁻³ moles of nitric acid is contained in 28.7 mL

molarity of nitric acid = 4.84 x 10⁻³ / 28.7 x 10⁻³

= .169 M .