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OpenStem
@openstem · Joined Jul 2026
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Quiz3 questions
What is the smallest particle of an element?
AA moleculeBAn atomCA compoundDA crystal
Chemistry · L2 · Atoms, Molecules, and Elements
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Chemistry · L2 · Atoms, Molecules, and ElementsQuiz3 questions
Which of these is a chemical change?
ACutting a piece of paperBMelting butterCBurning woodDDissolving sugar
Chemistry · L2 · Physical and Chemical Changes
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Chemistry · L2 · Physical and Chemical ChangesQuiz6 questions
What determines an element's position in the periodic table?
AThe colour of the elementBIts atomic number — the number of protonsCThe year it was discoveredDHow heavy a single atom feels
Chemistry · L2 · Periodic Table Basics
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Chemistry · L2 · Periodic Table BasicsQuiz5 questions
What is the full range of the pH scale?
A0 to 7B0 to 10C0 to 14D1 to 100
Chemistry · L2 · Acids, Bases & the pH Scale
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Chemistry · L2 · Acids, Bases & the pH ScaleQuiz6 questions
In the word equation 'magnesium + oxygen → magnesium oxide', which substances are the reactants?
AMagnesium oxide onlyBMagnesium and oxygenCOxygen onlyDThere are no reactants shown
Chemistry · L2 · Chemical Reactions & Word Equations
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Chemistry · L2 · Chemical Reactions & Word EquationsQuiz5 questions
Which technique would you use to separate sand from water?
AFiltrationBEvaporationCDistillationDChromatography
Chemistry · L2 · Separating Mixtures
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Chemistry · L2 · Separating MixturesQuiz6 questions
Which pair of metals sits at the very top of the reactivity series (most reactive)?
AGold and platinumBPotassium and sodiumCIron and copperDAluminium and zinc
Chemistry · L2 · Metals and Reactivity
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Chemistry · L2 · Metals and ReactivityQuiz5 questions
What is the correct chemical symbol for sodium?
ASBSoCNaDN
Chemistry · L2 · Elements, Compounds & Chemical Formulae
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Chemistry · L2 · Elements, Compounds & Chemical FormulaeQuiz5 questions
In a cup of sweet tea, sugar is dissolved in hot water. What is the sugar called?
AThe solventBThe soluteCThe solutionDThe mixture
Chemistry · L2 · Solubility and Solutions
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Chemistry · L2 · Solubility and SolutionsQuiz6 questions
Which three things make up the fire triangle?
AFuel, oxygen, and heatBWater, salt, and sugarCWood, coal, and oilDSmoke, ash, and soot
Chemistry · L2 · Combustion and Fuels
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Chemistry · L2 · Combustion and FuelsQuiz5 questions
What does density measure?
AHow heavy an object isBHow much space an object takes upCHow much mass is packed into a given volumeDHow many atoms an object contains
Chemistry · L2 · Density
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Chemistry · L2 · DensityQuiz5 questions
What makes a solid a crystal?
AIt is always clear and colourlessBIts particles are arranged in a regular, repeating patternCIt can only be made by humansDIt has no fixed shape
Chemistry · L2 · Crystals and Crystallization
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Chemistry · L2 · Crystals and CrystallizationQuiz6 questions
Which gas makes up the largest share of the air?
AOxygenBNitrogenCCarbon dioxideDArgon
Chemistry · L2 · Gases in the Air
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Chemistry · L2 · Gases in the AirQuiz5 questions
What is a polymer?
AA single small moleculeBA long chain made of many repeating monomer unitsCA type of metalDA liquid that never solidifies
Chemistry · L2 · Polymers and Plastics
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Chemistry · L2 · Polymers and PlasticsQuiz5 questions
What does a corrosive hazard symbol warn you about?
AThe substance catches fire easilyBThe substance can damage skin, eyes, or metal on contactCThe substance makes other materials burn more fiercelyDThe substance is harmless in small amounts
Chemistry · L2 · Chemical Safety and Hazard Symbols
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Chemistry · L2 · Chemical Safety and Hazard SymbolsQuiz5 questions
What happens to the temperature of the surroundings in an exothermic reaction?
AIt increases — energy is releasedBIt decreases — energy is absorbedCIt stays exactly the sameDIt cannot be predicted
Chemistry · L2 · Energy in Chemical Reactions
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Chemistry · L2 · Energy in Chemical ReactionsQuiz6 questions
Which general word equation describes neutralization?
Ametal + acid → salt + hydrogenBacid + base → salt + waterCacid + metal carbonate → salt + water + carbon dioxideDsalt + water → acid + base
Chemistry · L2 · Making Salts
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Chemistry · L2 · Making SaltsQuiz6 questions
What is the general word equation for a metal reacting with an acid?
Ametal + acid → salt + oxygenBmetal + acid → salt + hydrogenCmetal + acid → salt + waterDmetal + acid → oxide + hydrogen
Chemistry · L2 · Metals Reacting with Acids
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Chemistry · L2 · Metals Reacting with AcidsQuiz6 questions
Which test identifies oxygen gas?
ADamp red litmus paper turns blueBA glowing splint relights into a flameCLimewater turns cloudyDA lit splint gives a squeaky pop
Chemistry · L2 · Testing for Gases
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Chemistry · L2 · Testing for GasesQuiz6 questions
What is fermentation?
AYeast burning sugar using oxygenBYeast breaking down sugar without using oxygenCA physical change where sugar just dissolvesDSugar cooling down until it turns solid
Chemistry · L2 · Fermentation
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Chemistry · L2 · FermentationQuiz5 questions
Why does a singlet carbene's cyclopropanation of an alkene proceed stereospecifically?
AIt reacts in a single concerted step with no intermediate that could rotate and scramble the alkene's original stereochemistryBSinglet carbenes never react with alkenes at allCSinglet carbenes always racemize the alkene before additionDSinglet carbenes only add to alkenes at very low temperature
Chemistry · L5 · Carbene Chemistry
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Chemistry · L5 · Carbene ChemistryQuiz5 questions
What metal is added to steel to make stainless steel, giving it its rust-resistance?
AChromiumBZincCTinDGold
Chemistry · L2 · Protecting Metal Structures
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Chemistry · L2 · Protecting Metal StructuresQuiz6 questions
Which best describes evaporation in terms of energy?
AEndothermic — it absorbs energy from its surroundingsBExothermic — it releases energy to its surroundingsCNo energy change happens at allDIt only happens at exactly 100°C
Chemistry · L2 · Energy in the Water Cycle
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Chemistry · L2 · Energy in the Water CycleQuiz6 questions
What is an alloy?
AA pure element found on the periodic tableBA mixture of a metal with one or more other elementsCA type of acid used to clean metalDA gas released when metal burns
Chemistry · L2 · Alloys — Mixing Metals for a Purpose
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Chemistry · L2 · Alloys — Mixing Metals for a PurposeQuiz6 questions
What happens to energy when a chemical bond is broken?
AEnergy is always taken inBEnergy is always given outCNo energy change happens at allDIt depends only on the temperature of the room
Chemistry · L2 · Energy Stored in Chemical Bonds
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Chemistry · L2 · Energy Stored in Chemical BondsQuiz5 questions
What pigment gives red cabbage juice its pH-indicating power?
AAnthocyaninBChlorophyllCCaroteneDMelanin
Chemistry · L2 · Natural pH Indicators
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Chemistry · L2 · Natural pH IndicatorsQuiz6 questions
In the particle picture, what causes gas pressure?
AOne large particle pushing steadily on the containerBCountless tiny particles constantly colliding with the container's wallsCThe container walls squeezing inward on their ownDGas particles sticking permanently to the walls
Chemistry · L2 · Gas Pressure — the Particle Picture
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Chemistry · L2 · Gas Pressure — the Particle PictureQuiz6 questions
Which gas turns clear limewater cloudy?
AOxygenBCarbon dioxideCCarbon monoxideDNitrogen
Chemistry · L2 · What Comes Out of a Flame
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Chemistry · L2 · What Comes Out of a FlameQuiz6 questions
What is the purpose of the screening step at a water treatment plant?
ATo kill bacteria and other pathogensBTo remove large debris like leaves and litterCTo let heavy particles settle to the bottomDTo trap fine particles in sand and gravel
Chemistry · L2 · Treating Water for Drinking
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Chemistry · L2 · Treating Water for DrinkingQuiz6 questions
Why is gold usually found as pure ('native') metal in the ground?
AIt is extremely unreactive, so it never combines with other elementsBIt is extracted from its ore by electrolysis before it is buriedCIt reacts with carbon underground to release itselfDGold ore is too rare to form
Chemistry · L2 · Getting Metals from Ores
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Chemistry · L2 · Getting Metals from Ores