Quantitative Chemistry, hard, multiple steps no help Flashcards
In a titration of potassium hydroxide with nitric acid, 50cm3 of a 3 moles/dm3 solution of KOH was used to completely neutralise a solution of nitric acid. What is the mass of potassium nitrate produced?
15.15g
20cm3 of NaOH is needed to completely neutralise 50cm3 of 1.5moles/dm3 of hydrochloric acid. What is the concentration of NaOH?
3.75moles/dm3
Element X has 80% of particles of an atomic mass of 50, 15.8% of an atomic mass of 51 and the remaining percentage has an atomic mass of 52. What is the average atomic mass number?
50.24
A compound has 6.85g of Barium, 1.60g of sulphur and 3.20g of oxygen. What is its empirical formula?
BaSO4
An element has the following isotopes: 250 particles of atomic mass number 138, 1550 particles of atomic mass number 140 and 75 particles of atomic mass number 141. What is the average atomic mass number?
139.77
50cm3 of ammonium hydroxide is titrated with 40cm3 of 0.125moles/dm3 of phosphoric acid to make ammonium phosphate according to the following equation:
3 NH4OH + H3PO4 = (NH4)3PO4 + 3 H2O
What is the concentration of ammonium hydroxide?
0.3 moles/dm3
Three isotopes have the atomic mass numbers 24 (48 particles), 26 (264 particles) and 28 (528 particles). What is the average atomic mass number?
27.75
10cm3 of a concentrated sulphuric acid solution is dissolved into 90cm3 of water and mixed. 12.5cm3 of a 1moles/dm3 ammonium hydroxide solution is placed into a conical flask. 25cm3 of the diluted acid is needed to completely neutralise the ammonium hydroxide according to this equation:
2NH4OH + H2SO4 = (NH4)2SO4 + H2O
What is the concentration of the original, concentrated sulphuric acid?
2.5 moles/dm3
A hydrocarbon contains 92.3% of carbon a the rest is made up of hydrogen.
a) What is its empirical formula?
b) What is its molecular formula, if the relative formula mass is 78?
a) CH
b) C6H6
Tina wants to make 5.35g of insoluble iron(lll)hydroxide according to the following equation:
3 NaOH + FeCl3 = Fe(OH)3 + 3NaCl
What is the mass of solid NaOH she has to weigh in to an excess of FeCl3 solution to get 5.35g of Fe(OH)3?
6.00g
A pure compound consists of 9.20g of Na, 2.40g of C and 9.60g of O.
What is its empirical formula?
Na2CO3
Ed wants to make hydrated magnesium sulphate from 250 cm3 of 2moles/dm3 sulphuric acid reacting with an excess of magnesium carbonate. What is the total expected mass of hydrated magnesium sulphate according to the following equation:
MgCO3 + H2SO4 + 10 H2O = MgSO4.10 H2O + H2O
Remember: MgSO4 has 10 molecules of water around it.
150g
A pure compound contains 0.048g of carbon, 0.008g of hydrogen and 0.160g of bromine.
a) What is its empirical formula?
b) What is its molecular formula if the relative formula mass is 216?
a) C2H4Br
b) C4H8Br2
