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OpenStem
@openstem · Joined Jul 2026
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Quiz5 questions
Why is the Haber process run at ~450°C instead of a lower temperature, which would favour a higher equilibrium yield of ammonia?
AA lower temperature would make the reaction too slow to be economicalBA lower temperature would shift the equilibrium toward the reactantsCThe iron catalyst only works above 450°CDAmmonia decomposes below 450°C
Chemistry · L3 · Industrial Equilibrium — Haber and Contact Processes — 5 Q
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Chemistry · L3 · Industrial Equilibrium — Haber and Contact Processes — 5 QQuiz6 questions
What does a buffer solution do when a small amount of acid or base is added?
AIt resists the pH change, keeping pH roughly steadyBIt instantly neutralises the solution to pH 7CIt causes a larger pH swing than plain water would showDIt changes colour but the pH itself is unaffected
Chemistry · L3 · Buffers — Resisting pH Change
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Chemistry · L3 · Buffers — Resisting pH ChangeQuiz6 questions
Which of these best describes what entropy measures?
AThe total mass of a systemBHow spread out or disordered energy and matter areCThe temperature of a system in degrees CelsiusDThe exact amount of heat a reaction releases
Chemistry · L3 · Entropy and the Second Law Quiz
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Chemistry · L3 · Entropy and the Second Law QuizQuiz6 questions
What is a reaction mechanism?
AThe single collision that turns reactants directly into productsBThe sequence of small elementary steps a reaction actually proceeds through, from reactants to productsCAnother name for the balanced overall chemical equationDA list of the four everyday factors that can speed a reaction up
Chemistry · L3 · Reaction Mechanisms and the Rate-Determining Step — 6 Q
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Chemistry · L3 · Reaction Mechanisms and the Rate-Determining Step — 6 QQuiz6 questions
Which pair of oxidation states does iron most commonly show in its compounds?
AFe⁺ and Fe²⁺BFe²⁺ and Fe³⁺CFe³⁺ and Fe⁴⁺DFe and Fe⁺
Chemistry · L3 · Transition Metals — Variable States and Color — 6 Q
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Chemistry · L3 · Transition Metals — Variable States and Color — 6 QQuiz5 questions
What two products does complete combustion of a hydrocarbon fuel produce in plenty of oxygen?
ACarbon dioxide and waterBCarbon monoxide and sootCHydrogen and oxygenDA shorter alkane and an alkene
Chemistry · L3 · Combustion and Cracking of Hydrocarbons — 5 Q
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Chemistry · L3 · Combustion and Cracking of Hydrocarbons — 5 QQuiz5 questions
HDPE and LDPE are both addition polymers of ethene, yet HDPE is rigid and LDPE is flexible. What best explains this difference?
AHDPE chains are cross-linked with sulfur, LDPE chains are notBHDPE has long, straight chains that pack tightly; LDPE has short, branched chains that pack looselyCHDPE is a condensation polymer while LDPE is an addition polymerDHDPE and LDPE are made from different monomers
Chemistry · L3 · Polymer Structure and Properties — 5 Q
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Chemistry · L3 · Polymer Structure and Properties — 5 QQuiz6 questions
Which two dissolved ions are responsible for making water 'hard'?
ASodium and chloride ionsBCalcium and magnesium ionsCPotassium and carbonate ionsDHydrogen and hydroxide ions
Chemistry · L3 · Water Hardness
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Chemistry · L3 · Water HardnessQuiz6 questions
Which two gases are chiefly responsible for acid rain?
ACarbon dioxide and oxygenBSulfur dioxide and nitrogen oxidesCMethane and hydrogenDOzone and helium
Chemistry · L3 · Acid Rain
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Chemistry · L3 · Acid RainQuiz6 questions
A rate vs concentration graph is a straight line passing through the origin. What is the reaction order?
AFirst orderBZero orderCSecond orderDCannot be determined from a graph
Chemistry · L3 · Reading Rate Graphs — 6 Q
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Chemistry · L3 · Reading Rate Graphs — 6 QQuiz6 questions
What does Avogadro's Law state?
AEqual volumes of any gases, at the same temperature and pressure, contain equal numbers of molesBEqual volumes of any gases always contain equal massesCEqual masses of any gases always contain equal numbers of molesDThe volume of a gas is independent of temperature and pressure
Chemistry · L3 · Avogadro's Law and Molar Gas Volume — 6 Q
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Chemistry · L3 · Avogadro's Law and Molar Gas Volume — 6 QQuiz6 questions
What type of reaction is esterification — an alcohol and a carboxylic acid combining to form an ester and water?
ANeutralizationBCondensationCCombustionDDisplacement
Chemistry · L3 · Esters — Formation and Uses — 6 Q
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Chemistry · L3 · Esters — Formation and Uses — 6 QQuiz6 questions
What does electronegativity describe?
AAn atom's tendency to pull the electrons it shares in a bond toward itselfBThe number of valence electrons an atom hasCAn atom's atomic massDThe number of bonds an atom can form
Chemistry · L3 · Electronegativity and Bond Polarity — 6 Q
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Chemistry · L3 · Electronegativity and Bond Polarity — 6 QQuiz6 questions
Which three metals commonly act as catalysts in a car's catalytic converter?
APlatinum, palladium and rhodiumBIron, nickel and copperCVanadium, manganese and chromiumDGold, silver and zinc
Chemistry · L3 · Catalysts in Industry — 6 Q
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Chemistry · L3 · Catalysts in Industry — 6 QQuiz6 questions
Using the criss-cross method on Ca²⁺ and NO3⁻, what is the correct formula for calcium nitrate?
ACaNO3BCa(NO3)2CCa2NO3DCa(NO3)3
Chemistry · L3 · Naming and Writing Ionic Formulae
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Chemistry · L3 · Naming and Writing Ionic FormulaeQuiz5 questions
What is the formula for the retention factor, Rf?
ARf = distance travelled by substance ÷ distance travelled by solvent frontBRf = distance travelled by solvent front ÷ distance travelled by substanceCRf = distance travelled by substance × distance travelled by solvent frontDRf = distance travelled by substance − distance travelled by solvent front
Chemistry · L3 · Chromatography and Rf Values
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Chemistry · L3 · Chromatography and Rf ValuesQuiz5 questions
What does a combustion analysis apparatus actually measure directly?
AThe mass of CO2 and the mass of H2O produced when a known mass of sample burns completelyBThe percent composition of the sample, read off an instrument displayCThe molar mass of the sample directlyDThe number of moles of oxygen gas consumed
Chemistry · L3 · Combustion Analysis — 5 Q
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Chemistry · L3 · Combustion Analysis — 5 QQuiz5 questions
How much heat is needed to melt 40 g of ice at 0 °C? Use the latent heat of fusion of ice, L_f = 334 J/g.
A13.36 kJB3.34 kJC133.6 kJD1.336 kJ
Chemistry · L3 · Specific Latent Heat Quiz
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Chemistry · L3 · Specific Latent Heat QuizQuiz5 questions
What fundamentally distinguishes a redox titration from an acid–base titration?
AThe titrant and analyte react via electron transfer, and the endpoint is a redox-driven colour change, not a pH indicator changeBRedox titrations never use a buretteCRedox titrations always require heating the flask to boilingDThere is no real difference — both types measure exactly the same thing
Chemistry · L3 · Redox Titrations
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Chemistry · L3 · Redox TitrationsQuiz7 questions
The structure below is caffeine, the stimulant in coffee and tea. How many nitrogen atoms does one caffeine molecule contain?
A2B3C4D6
Chemistry · L3 · Reading Structures, Equations & Curves — 7 Q
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Chemistry · L3 · Reading Structures, Equations & Curves — 7 QQuiz10 questions
Which functional group is present in CH₃COOH (ethanoic acid)?
AAldehyde (–CHO)BKetone (C=O)CCarboxylic acid (–COOH)DEster (–COO–)
Chemistry · L4 · Organic Chemistry Basics — 10 Q
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Chemistry · L4 · Organic Chemistry Basics — 10 QQuiz10 questions
Which set of quantum numbers is NOT valid for an electron?
An=2, l=1, mₗ=0, mₛ=+½Bn=3, l=2, mₗ=−2, mₛ=−½Cn=2, l=2, mₗ=0, mₛ=+½Dn=4, l=0, mₗ=0, mₛ=+½
Chemistry · L4 · Atomic Structure & Periodicity — 10 Q
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Chemistry · L4 · Atomic Structure & Periodicity — 10 QQuiz10 questions
How many moles of CO₂ are produced by burning 44 g of propane (C₃H₈, M = 44 g/mol) in excess oxygen? (C₃H₈ + 5O₂ → 3CO₂ + 4H₂O)
A1 molB2 molC3 molD5 mol
Chemistry · L4 · Stoichiometry & Equilibrium — 10 Q
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Chemistry · L4 · Stoichiometry & Equilibrium — 10 QQuiz6 questions
Given E°(Ag⁺/Ag) = +0.80 V and E°(Zn²⁺/Zn) = −0.76 V, what is E°cell for the spontaneous cell built from this pair?
A+1.56 VB+0.04 VC−1.56 VD+0.80 V
Chemistry · L4 · Electrochemistry — 6 Q
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Chemistry · L4 · Electrochemistry — 6 QQuiz5 questions
In the complex [Cu(NH₃)₄]²⁺, what role does each NH₃ molecule play?
AA Lewis acid accepting an electron pair from copperBA Lewis base donating a lone pair to copperCA spectator ion with no bond to copperDA reducing agent that lowers copper's oxidation state
Chemistry · L4 · Coordination Chemistry — 5 Q
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Chemistry · L4 · Coordination Chemistry — 5 QQuiz6 questions
A solute dissolves and ideally dissociates into 3 ions per formula unit (like K₂SO₄). What is its van't Hoff factor i?
A1B2C3D4
Chemistry · L4 · Colligative Properties (Quantitative) — 6 Q
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Chemistry · L4 · Colligative Properties (Quantitative) — 6 QQuiz6 questions
For the equilibrium Ag₂CrO₄(s) ⇌ 2 Ag⁺(aq) + CrO₄²⁻(aq), which is the correct Ksp expression?
AK_{sp} = [\text{Ag}^+][\text{CrO}_4^{2-}]BK_{sp} = [\text{Ag}^+]^2[\text{CrO}_4^{2-}]CK_{sp} = 2[\text{Ag}^+][\text{CrO}_4^{2-}]DK_{sp} = [\text{Ag}_2\text{CrO}_4][\text{Ag}^+]^2[\text{CrO}_4^{2-}]
Chemistry · L4 · Solubility Equilibria (Ksp) — 6 Q
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Chemistry · L4 · Solubility Equilibria (Ksp) — 6 QQuiz6 questions
Dipole moment is a vector quantity. What two things does that mean it has?
AOnly a magnitude, measured in debyeBA magnitude AND a directionCOnly a direction, from negative to positiveDA magnitude and a sign (positive or negative), but no direction
Chemistry · L4 · Intermolecular Forces & Molecular Polarity — 6 Q
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Chemistry · L4 · Intermolecular Forces & Molecular Polarity — 6 QQuiz6 questions
What is the final product when a primary alcohol is oxidized with excess hot acidified KMnO₄?
AAn aldehydeBA ketoneCA carboxylic acidDAn ester
Chemistry · L4 · Organic Chemistry II — Oxidation Ladder & Carboxylic Acids Quiz
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Chemistry · L4 · Organic Chemistry II — Oxidation Ladder & Carboxylic Acids QuizQuiz6 questions
According to Hückel's rule, how many π electrons must a planar, cyclic, fully conjugated ring have to be aromatic?
A4n π electronsB4n + 2 π electronsC2n + 4 π electronsDn π electrons
Chemistry · L4 · Aromatic Chemistry & EAS — 6 Q
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Chemistry · L4 · Aromatic Chemistry & EAS — 6 Q