REFSTUDY GUIDE: Big IdeasUse to answer form questions
1.Reaction rate measures how fast a reaction proceeds — how quickly a reactant disappears or a product appears — and it is distinct from the total amount of product, which is set by the limiting reactant. Two flasks running the same reaction can finish in 15 seconds or 3 hours and still produce the same total product; what changes is the speed of the rearrangement, not the chemistry. Rate is therefore a fifth piece of evidence for a reaction, alongside the W1 evidence types (color, gas, temperature, precipitate).
2.Collision theory explains the mechanism behind every rate factor: reactions happen only when particles collide with enough kinetic energy (≥ activation energy) and in the right orientation. Anything that increases the frequency of collisions (concentration, surface area) OR the fraction of collisions with enough energy (temperature, catalyst) speeds the reaction up. Temperature does both at once, which is why raising it ~10 °C often roughly doubles the rate.
3.A catalyst opens an alternative reaction pathway with a lower activation-energy hill, so a far greater fraction of collisions succeed; unlike a reactant, the catalyst is not consumed by the reaction and emerges intact (it can be reused). Enzymes inside your body are biological catalysts that make life-sustaining reactions fast enough at body temperature. Industrial catalysts let chemical plants run at lower temperatures and pressures than would otherwise be required.
DRAWKEY TERMSGoogle each → Images tab → sketch what you see
OTHER VOCAB: concentration · surface area
Reaction Rate
Speed at which a chemical reaction proceeds
Catalyst
Substance that speeds up a reaction without being consumed
Collision Theory
Reactions occur when particles collide with enough energy
Activation Energy
Minimum energy needed to start a chemical reaction
WRITEFOCUS QUESTIONYour initial thinking
Bread dough rises in 45 minutes on a hot summer afternoon but takes over 3 hours in a cold winter kitchen. The yeast reaction is the same; only the speed changes. The same is true everywhere — rust forms slowly, fires burn quickly, milk spoils faster on the counter than in the fridge. Same atoms, same products: different conditions, very different rates.
Why does food cook faster on a hot day than a cold day?
I think...
WRITEAFTER HOOK FORMReflect before continuing
I learned that...
WRITETemperature & Activation Energy
Station 1 — Temperature & Activation Energy
As temperature increased from 5 °C → 50 °C, rate ___ because:
Collision-theory explanation:
In my own words, "activation energy" is:
CHECKDAY 1 CHECK-INBefore you leave
Q1:Based on today's investigation of reaction rates & factors, explain
one key finding using evidence from your data. Connect your answer
to this week's focus question: Why does food cook faster on a hot
day than a cold day?
Confidence:
Reaction Rates & Factors (Day 2)
Name: Period:
Main idea I observed:
Evidence from my data:
I can apply this by:
WRITECatalysts & Reaction-Rate Design
The main idea about catalysts is...
This connects to Week 1 (evidence of reaction) because...
I can apply collision theory by...
DRAWCONCEPT MODELEnergy diagram: with vs. without catalyst
Sketch the energy diagram (energy y, reaction progress x) for
the SAME reaction WITHOUT vs. WITH a catalyst. Show reactant
+ product levels and the activation-energy (Ea) hill for
both — the catalyzed hill is lower. Add a particle-collision
inset; label ≥3 word-bank terms.
Word Bank: activation energy · catalyst ·
collision theory · reactants · products
≥3 word bank terms labeled
Two Ea hills shown (catalyzed is lower)
Reactant/product levels unchanged by catalyst
CHECKTEST YOUR THINKINGRate each: FALSE ← 1-2-3-4-5 → TRUE · 4 new + 1 last week + 1 spiral
1. Doubling the concentration of one reactant doubles the total amount of product made.
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2. A catalyst is used up by the reaction it speeds up.
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3. At a given temperature, every particle in a sample has exactly the same kinetic energy.
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4. Reaction rate and total amount of product are the same thing — a faster reaction ALWAYS produces more total product.
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5. [Last week] When something burns, mass disappears because the material is destroyed in the flame.
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6. [Spiral · C5 Kinetic Energy] A hotter object always contains MORE particles than a colder object of the same material — that is why it has more thermal energy.
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Pick any TWO statements -- especially any you rated 2, 3, or 4. Justify your rating with evidence:
Statement #___ -- I rated it ___ because:
Statement #___ -- I rated it ___ because:
THINKSCIENTIST CIRCLE DEBRIEFReflect after your Scientist Circle discussion
AHA! Moment
The one I changed my thinking most about is...
Remaining Question
I still wonder...
WRITEFOCUS QUESTION REVISITFinal written response
Why does food cook faster on a hot day than a cold day?
Word Bank: reaction rate · catalyst · collision theory · activation energy · concentration · surface area