Convert concentration units and calculate unknown concentration from titration data.
| English | Chinese |
|---|---|
| concentration | 浓度 |
| solution volume | 溶液体积 |
| titration | 滴定 |
Try each question before opening its hint or answer. Use paper for calculations and diagrams.
Why does the expression 0.100 × 20.0 give the wrong number of moles for 20.0 cm³ solution?
Use the relationships above and check particle ratios and units.
The volume must be in dm³: use 0.0200, not 20.0.
4.0 g NaOH is made up to 250 cm³ solution. Find concentration in g/dm³ and mol/dm³. M = 40 g/mol.
Convert 250 cm³ to dm³; use mass or moles per volume.
4.0/0.250 = 16 g/dm³; (4.0/40)/0.250 = 0.40 mol/dm³.
HCl + NaOH → NaCl + H₂O. Find the volume of 0.100 mol/dm³ NaOH needed for 25.0 cm³ of 0.200 mol/dm³ HCl.
Find acid moles, use the 1:1 ratio and then calculate alkali volume.
n(HCl) = 0.200 × 0.0250 = 0.00500 mol. V(NaOH) = 0.0500 dm³ = 50.0 cm³.
Use Lesson 4 in your worksheet for written practice. Your teacher will discuss those answers in class.