Reactants & Products
These are the starting substances in a chemical reaction.
Reactants
Melting ice is this type of change.
Physical change
In a chemical equation, this symbol separates reactants from products.
the arrow (→)
Reaction rate describes this about a chemical reaction.
how fast a reaction happens
Collision theory says particles must do this in order to react.
Collide
These are the substances formed at the end of a chemical reaction.
Products
Burning paper is this type of change.
Chemical change
In the equation 2H₂ + O₂ → 2H₂O, this number shows how many molecules are involved.
coefficient
Increasing temperature usually makes reactions happen this way.
faster / faster reaction rate
Particles must collide with enough of this to react successfully.
Energy
In the reaction Iron + Oxygen → Iron oxide, these are the reactants.
iron and oxygen
This type of change does NOT create a new substance.
Physical Change
Identify the reactants in this equation: CaCO₃ → CaO + CO₂
CaCO₃
Name two factors that increase reaction rate
higher temperature, greater surface area, stirring/mixing, higher concentration, catalyst
Write a chemical equation for hydrogen reacting with oxygen to form water.
2H₂ + O₂ → 2H₂O
The arrow (→) in a chemical equation means this.
A reaction has occurred. The direction of a chemical reaction
A student heats blue copper sulfate crystals and they turn white. When water is added, they turn blue again.
Is this a physical or chemical change? Explain your reasoning.
Chemical change occurred when heated because a new substance (anhydrous copper sulfate) formed. The colour change and need to add water to reverse it indicates a chemical reaction.
Identify the products in this equation: Zn + 2HCl → ZnCl₂ + H₂
ZnCl₂ and H₂
Explain why powdered substances often react faster than large pieces.
powder has more surface area, so more collisions occur
According to collision theory, why do not all particle collisions result in a reaction?
Particles must collide with enough energy and correct orientation. If energy is too low or particles are not aligned properly, no reaction occurs.
Write a word equation for magnesium reacting with oxygen.
magnesium + oxygen → magnesium oxide
Explain how you know rusting is a chemical change.
a new substance is formed (iron oxide/rust) and the change is difficult to reverse
Explain why the number of atoms must be the same on both sides of a chemical equation.
atoms are not created or destroyed (law of conservation of mass)
A reaction takes 5 minutes at 20°C and 1 minute at 40°C. Explain why increasing temperature increases reaction rate using particle theory.
Higher temperature gives particles more kinetic energy, so they move faster and collide more often. Collisions are also more energetic, increasing the chance of a successful reaction.
Explain why increasing temperature increases successful collisions.
particles move faster, causing more frequent and energetic collisions