1.9 questions Flashcards
What volume of 0.25 moldm-3 sodium hydroxide solution is required to neutralise 25.0cm3 of 0.15 moldm-3 sulfuric acid.
0.03dm
What volume of 0.30 moldm-3 sodium hydroxide solution is required to neutralise 25.0cm3 of 0.125 moldm-3 nitric acid.
0.0104dm
What volume of 0.125 moldm-3 calcium hydroxide solution is required to neutralise 25.0cm3 of 0.15 moldm-3 hydrochloric acid.
0.015
What is the concentration of calcium hydroxide solution if 20cm3 of it is required to neutralise 25.0cm3 of 0.15 moldm-3 sulfuric acid.
0.1875
A standard solution was prepared by dissolving 2.6061g of anhydrous sodium carbonate in distilled water and making up to 250cm3. A 25cm3 portion of this was titrated against hydrochloric acid. 18.7cm3 of hydrochloric acid was required for neutralisation. Calculate the concentration of the hydrochloric acid using the hints below
0.263
A 25g sample of household cleaning fluid containing ammonia was dissolved in water and made up to 250cm3. A 25cm3 portion of this solution required 29.4cm3 of 0.25 moldm-3 sulfuric acid for neutralisation. Calculate the percentage by mass of ammonia in the cleaning fluid.
10%
A marble chip of mass 2.5g required 28.0cm3 of 1.5moldm-3 hydrochloric acid to react with all of the calcium carbonate in the marble. Calculate the % by mass of calcium carbonate in the marble chip.
84%
A solution is made by dissolving 5.0g of impure sodium hydroxide in water and making it up to 1dm3 of solution. 25.0cm3 of this solution is neutralised by 30.3cm3 of hydrochloric acid of concentration 0.102 moldm-3. Calculate the % purity of the sodium hydroxide.
98.9%
27.823g of sodium carbonate were dissolved in water and made up to 1.0dm3. 25cm3 of this solution was neutralised by 48.8cm3 of hydrochloric acid of concentration
moldm-3. Find n in the formula Na2CO3.nH2O
10
This is a challenging calculation which is classed as a “back titration”. A 1.00g sample of limestone is allowed to react with 100cm3 of 0.20 moldm-3 hydrochloric acid. The excess acid required 24.8cm3 of 0.1 moldm-3 sodium hydroxide. Calculate the % of calcium carbonate in the limestone.
87.6%
This is a challenging calculation which is classed as a “back titration”. 0.50g of fertiliser containing ammonium sulfate is warmed with sodium hydroxide solution. The ammonia evolved was absorbed in 100cm3 of 0.1moldm-3 hydrochloric acid. The excess of hydrochloric acid required 55.9cm3 of 0.1moldm-3 sodium hydroxide for neutralisation. Calculate the % of ammonium sulfate in the sample. The equations are
(NH4)2SO4 + 2NaOH -> 2NH3 + Na2SO4 + 2H2O
NH3 + HCl -> NH4Cl
HCl + NaOH -> NaCl + H2O
58.2%
