Concentration Of Solutions (GCSE Chemistry)

A diluted sample has concentration 0.0250 mol/dm3. If the dilution factor from stock to sample was 1 in 20, what was the stock concentration?

25.0 cm3 of hydrochloric acid is neutralised by 20.0 cm3 of 0.100 mol/dm3 sodium hydroxide. What is the concentration of the hydrochloric acid in mol/dm3? (HCl + NaOH ? NaCl + H2O)

A burette delivered 23.50 cm3 of 0.100 mol/dm3 Ba(OH)2. How many moles of hydroxide ions (OH–) were provided by that volume? (Ba(OH)2 provides 2 OH– per formula unit.)

When carrying out a titration, the burette reading is recorded as 12.35 cm3 at start and 35.75 cm3 at end. What volume of titrant was delivered?

A student dissolves mass m of solute of Mr 120 to make 250 cm3 of solution. Which expression gives the concentration in mol/dm3?

A student prepares 100.0 cm3 of 0.100 mol/dm3 NaOH by diluting a 1.00 mol/dm3 stock. What volume of stock is needed (in cm3)?

A student dissolves 0.500 g of NaCl (Mr = 58.5) in 100 cm3 water. What is the concentration in mol/dm3?

When making up solutions, why should you add solid to water rather than water to solid?

A student titrates 25.00 cm3 of HCl with 23.50 cm3 of 0.100 mol/dm3 Ba(OH)2. Using 2HCl + Ba(OH)2 ? BaCl2 + 2H2O, what is the concentration of HCl (mol/dm3)?

In a titration the end-point volumes are 23.90, 23.45, 23.55, 23.55, 23.45 cm3. Why might the student use 23.50 cm3 for calculations instead of a single raw value?

If a saturated solution at a given temperature cannot dissolve any more solute, what happens to the concentration if extra solid solute is added?