Could you guys help me with these questions pls. Thank you

8.4) 27.1 cm³

8.5) 0.217 mol/dm³

Explanation:

Please see attached picture for full solution.

8.4) Since the results from titrations 3-5 are within 0.10cm³ from each other, these 3 results are concordant.

8.5) Find mol of sulfuric acid to find mol of NaOH using mole ratio. Equation has already been balanced for you, so mole ratio of NaOH to H2S04 is 2:1. To find concentration of NaOH, divide the number of moles by the volume in dm³ since the units for concentration is mol/dm³, which you can think of as the number of moles of NaOH in a dm³ of solution.

1 dm³ = 1000cm³

Thus, 1cm³= 1/1000 dm³

- lead + phosphoric acid = hydrogen + lead(ii) phosphate

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements