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  1. Problems
  2. /Atoms and Molecules

Atoms and Molecules

Chemistry
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64 problems
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1.
Concentrated sulphuric acid is 98% H₂SO₄ by mass, and its density is 1.84 g mL⁻¹. New
High School (11–12) · Stoichiometry and Concentration, The Mole ConceptStemPy LabStemPy Lab
Hard
2.
A bottle is labelled sodium hydroxide, 3.0 M, density 1.11 g mL⁻¹. New
High School (11–12) · Stoichiometry and Concentration, The Mole ConceptStemPy LabStemPy Lab
Hard
3.
Antifreeze has ethylene glycol, C₂H₆O₂ (62 g mol⁻¹), dissolved in water. New
High School (11–12) · Stoichiometry and Concentration, The Mole ConceptStemPy LabStemPy Lab
Medium
4.
The saline drip used in hospitals has 0.9 g of sodium chloride in every 100 mL of solution. New
High School (11–12) · Stoichiometry and Concentration, The Mole ConceptStemPy LabStemPy Lab
Easy
5.
A solution with 3.40 g of silver nitrate is mixed with one holding 2.34 g of sodium chloride. New
High School (11–12) · Stoichiometry and Concentration, The Mole ConceptStemPy LabStemPy Lab
Hard
6.
In a blast furnace, carbon monoxide takes the oxygen from haematite: Fe₂O₃ + 3CO → 2Fe + 3CO₂. New
High School (11–12) · Stoichiometry and Concentration, The Mole ConceptStemPy LabStemPy Lab
Medium
7.
Kabir drops 13 g of zinc into a solution that holds 7.3 g of hydrogen chloride: Zn + 2HCl → ZnCl₂ +… New
High School (11–12) · Stoichiometry and Concentration, The Mole ConceptStemPy LabStemPy Lab
Medium
8.
A lighter holds butane, which burns as 2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O. New
High School (11–12) · Stoichiometry and Concentration, The Mole ConceptStemPy LabStemPy Lab
Easy
9.
A chemist burns 0.230 g of a liquid that holds only carbon, hydrogen and oxygen. New
High School (11–12) · Stoichiometry and Concentration, Molecules, Ions and FormulaeStemPy LabStemPy Lab
Hard
10.
A fuel gas is 82.8% carbon and 17.2% hydrogen by mass. New
High School (11–12) · Stoichiometry and Concentration, Molecules, Ions and FormulaeStemPy LabStemPy Lab
Medium
11.
Orange crystals used in the laboratory are 26.6% potassium, 35.4% chromium and 38.0% oxygen by mass. New
High School (11–12) · Stoichiometry and Concentration, Molecules, Ions and FormulaeStemPy LabStemPy Lab
Medium
12.
A farmer can buy urea, CO(NH₂)₂, ammonium nitrate, NH₄NO₃, or ammonium sulphate, (NH₄)₂SO₄. New
High School (11–12) · Stoichiometry and Concentration, Molecules, Ions and FormulaeStemPy LabStemPy Lab
Easy
13.
Gold has a molar mass of 196.97 g mol⁻¹. New
High School (11–12) · The Mole ConceptStemPy LabStemPy Lab
Hard
14.
A stick of chalk is 10.0 g of calcium carbonate, CaCO₃, of molar mass 100.09 g mol⁻¹. New
High School (11–12) · The Mole ConceptStemPy LabStemPy Lab
Medium
15.
A drip bag holds 90.08 g of glucose, C₆H₁₂O₆, of molar mass 180.16 g mol⁻¹. New
High School (11–12) · The Mole ConceptStemPy LabStemPy Lab
Easy
16.
Aluminium sulfate, Al₂(SO₄)₃, is used to make water clear. New
High School (11–12) · The Mole Concept, Molecules, Ions and FormulaeStemPy LabStemPy Lab
Medium
17.
Gallium has two isotopes: gallium-69 of mass 68.926 u and gallium-71 of mass 70.925 u. New
High School (11–12) · The Mole Concept, Molecules, Ions and FormulaeStemPy LabStemPy Lab
Hard
18.
Silicon has three isotopes: silicon-28 of mass 27.977 u (92.23%), silicon-29 of mass 28.976 u… New
High School (11–12) · The Mole Concept, Molecules, Ions and FormulaeStemPy LabStemPy Lab
Medium
19.
Urea, CO(NH₂)₂, is a fertiliser. Find its molecular mass, with C = 12.01 u, O = 16.00 u, N = 14.01… New
High School (11–12) · The Mole Concept, Molecules, Ions and FormulaeStemPy LabStemPy Lab
Easy
20.
At 110 °C and a fixed pressure, Meera sparks 50 mL of hydrogen with 20 mL of oxygen. New
High School (11–12) · Laws of Chemical Combination, The Mole ConceptStemPy LabStemPy Lab
Hard
21.
Sulfur forms two oxides. Oxide A is 50.0% sulfur by mass, and oxide B is 40.0% sulfur. New
High School (11–12) · Laws of Chemical Combination, The Mole ConceptStemPy LabStemPy Lab
Medium
22.
Two black powders are reduced to the metal. New
High School (11–12) · Laws of Chemical Combination, The Mole ConceptStemPy LabStemPy Lab
Medium
23.
Arun heats 24.5 g of potassium chlorate in a test tube. New
High School (11–12) · Laws of Chemical Combination, The Mole ConceptStemPy LabStemPy Lab
Easy
24.
A car goes 16 km on one litre of petrol. New
High School (11–12) · Measurement, Units and Significant FiguresStemPy LabStemPy Lab
Easy
25.
Gold can be beaten into a very thin leaf. New
High School (11–12) · Measurement, Units and Significant FiguresStemPy LabStemPy Lab
Hard
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