Energy changes: Theory Flashcards
Explain Chemical energy
The energy contains in any substances that can be used as fuels
Some examples of Chemical energy usage
Example: Combustion reaction with fuels such as wood or coal, to produce thermal and light energy (and other usages and examples)
Explain Energy changes
Transformation or Movement of energy from one form to another
Energy change is responsible for changes in ___ and ___ reactions.
Matter of states, Chemical
3 types of Heat transfer
Radiation, Conduction and Convection
Exothermic reactions ___ energy as the surroudings get hotter.
release
Endothermic reactions ___ energy when they get cold
take in / absorb in
Most chemical reactions are ___.
exothermic
Explain how Exothermic reactions work.
Exothermic reactions release (or) produce thermal energy to the surroundings, due to the temperature and heat.
Explain how Endothermic reactions work.
Endothermic reactions absorb in (or) take in heat energy from the surroundings.
Evaporation is an (exothermic/endothermic) reaction.
endothermic
Melting is an (exothermic/endothermic) reaction.
endothermic
You can identify the type of reactions by looking at the ___.
temperature changes
Neutralization is an (exothermic/endothermic) reaction.
exothermic
Freezing is an (exothermic/endothermic) reaction.
exothermic
What are the products of combustion?
The substances that are created when a fuel burns
What are the products of combustion?
The substances that are created when a fuel burns
Diesel is separated from ___.
Crude oil
Crude oil was found over millions of years from ___.
Dead animals
Crude is a ___ source.
non-renewable
Hydrogen fuel’s source
Methane
What is Methane formed with?
Animal waste, rubbish dump
Methane is a ___ source.
renewable
Ethanol fuel is from plants, such as ___.
sugar cane
Ethanol’s a ___ source.
renewable
Diesel and Ethanol are in ___ state at 20*C.
Liquid
Hydrogen’s state at 20*C
Gas
Hydrogen can be ___ and dangerous.
Explosive
…
Some questions can’t be answered scientifically, yet the answer can be based on the people’s opinions and beliefs.
Equation for calculating the heat transferred to water
(not necessary)
H = m * c * △T
(H = heat transferred to water,
m = mass of the water,
c = heat capacity of the water,
△T = temperature change)
