Chemical Reactions Basics
This is what happens when substances change into new substances.
What is a chemical reaction?
This type of reaction releases heat to the surroundings.
What is an exothermic reaction?
A system that can exchange matter and energy with its surroundings.
What is an open system?
Bubbles forming in a reaction usually means this is being produced.
What is gas?
The goal of an MRE heater reaction is to produce this kind of energy.
What is heat (thermal energy)?
These are the starting substances in a chemical reaction.
What are reactants?
This type of reaction absorbs heat from the surroundings.
What is an endothermic reaction?
A system that does not let matter in or out (but may allow energy).
What is a closed system?
A temperature probe is used to measure this in a reaction.
What is temperature change?
To heat food, students need a reaction that is this type.
What is exothermic?
These are the substances formed after a chemical reaction.
What are products?
In an exothermic reaction, the temperature of the surroundings usually does this.
What is increases?
In an open system, gas escaping can make the mass appear to do this.
What is decrease?
If the temperature rises quickly, the reaction is likely this type.
What is exothermic?
A reaction that heats up to about 60°C is useful because it can…
What is warm/cook food safely?
Evidence that a chemical reaction happened might include gas, temperature change, or…
What is color change (or new solid/precipitate forming)?
In an endothermic reaction, the temperature of the surroundings usually does this.
What is decreases?
In a closed system, the mass before and after the reaction should do this.
What is stay the same?
If the temperature drops, energy is being taken in by the reaction, meaning it is…
What is endothermic?
This is why a strong exothermic reaction can be dangerous if uncontrolled.
What is it can overheat and burn/melt materials?
This is the scientific rule that says matter cannot be created or destroyed in a reaction.
What is the Law of Conservation of Mass?
This is stored energy in chemical bonds.
What is chemical energy?
A sealed bag reaction is used in class because it helps prove this law.
What is conservation of mass?
A graph showing temperature over time helps you identify this.
What is energy change during a reaction?
In designing a heater, insulation helps because it reduces…
What is heat loss to the surroundings?