Energy & Heat
What type of energy increases when temperature increases?
Kinetic energy
What is the first step in any stoichiometry problem?
Convert grams to moles
What type: A + B → AB
Synthesis
What must happen for a reaction to occur?
Particles must collide
What formula is used for percent yield?
(actual ÷ theoretical) × 100
Which requires more energy to heat up: a substance with high or low specific heat?
High specific heat
What does a balanced equation give you for calculations?
Mole ratios
What type: AB → A + B
Decomposition
What is required for collisions to be successful?
Enough energy (activation energy)
If actual yield is smaller than theoretical, percent yield is…?
Less than 100%
In an exothermic reaction, is energy absorbed or released?
Released
In 2H₂ + O₂ → 2H₂O, what is the mole ratio of H₂ to O₂?
2:1
What type: A + BC → AC + B
Single replacement
What law states mass is conserved?
Law of Conservation of Mass
What does specific heat measure?
Energy needed to raise temperature
What happens to energy during an endothermic reaction?
It is absorbed
What is the limiting reactant?
The reactant that runs out first
What type: AB + CD → AD + CB
Double replacement
Closed system: what can move in/out?
Energy only
What is the last element you balance in combustion reactions?
Oxygen
A hot metal is placed in water. Who gains energy?
The water (and surroundings)
What does molar mass tell you about a substance?
The mass of one mole of that substance
What type of reaction is CH₄ + O₂ → CO₂ + H₂O?
Combustion
Why do chemists use moles?
To count particles consistently
What determines how much product is made?
Limiting reactant