Module 2 Flashcards
What do all chemical reactions produce?
A new substance
In a word equation what side should a reactant appear on?
The left
In a word equation what side should a product appear on?
The right
In a word equation what should be used instead of an = sign
An arrow
In a word equation what are the state symbols?
Solid (s)
Liquid (l)
Gas (g)
Aqueous (aq)
What is an aqueous?
A substance dissolved in water
How are state symbols written in a word equation?
In subscript
What is the word equation for carbon dioxide? (example of a word equation)
Carbon(g) + oxygen(g) —> carbon dioxide(g)
Energy is given out in…
An exothermic reaction
What happens to the temperature in an exothermic reaction?
It increases
Burning is an example of an exothermic reaction.
What happens to energy in an endothermic reaction?
The energy is taken in
What happens to the temperature in an endothermic reaction?
It decreases
Electrolysis is an example of an endothermic reaction.
Explain electrolysis
It uses electricity to separate compounds into the elements they contain.
What is a fuel?
A chemical burned to release energy
What happens during the combustion of fuel?
Heat energy is given out
Combustion is …
The term used to describe the burning of a fuel in the presence of oxygen
When a fuel is burned, what does it react with in the air?
Oxygen
What is the % of oxygen we breathe in?
21%
What is the test for oxygen?
Relights a glowing splint
What happens when carbon reacts with oxygen in the air?
It forms carbon dioxide
Carbon(s) + oxygen(g) —> carbon dioxide(g)
What is the test for carbon dioxide?
Turns limewater milky
What is the difference between incomplete and complete combustion?
The products of complete combustion are carbon dioxide and water. Incomplete combustion occurs when insufficient oxygen is present.
Describe carbon monoxide gas.
Carbon monoxide gas is a colourless, ouderless toxic gas
What is the Word equation for the combustion of hydrogen?
Hydrogen reacts with oxygen in the air to form water
Hydrogen(g) + oxygen(g) —> water(l)
What is the test for hydrogen?
Hydrogen gas burns with a squeaky pop
Why is hydrogen described as the fuel of the future?
Using renewable energy, water molecules can be split electrolysis to produce hydrogen and oxygen.
The hydrogen reacts with oxygen to release energy (exothermic reaction)
The only product of combustion is water.
What are the fossil fuels?
Coal, oil and natural gas
How was coal formed?
Millions of years ago giant plants died. Over the next million of years these plants were buried under water and dirt. HEAT and PRESSURE turned these dead plants into COAL.
How were oil and natural gas formed?
Plankton died and were buried in the ocean floor and over time they were covered by layers of silt and sand. Over millions of years the remains turned to oil and gas due to enormous HEAT and PRESSURE. Today we drill though the layers of silt, sand and rock to reach rock formations containing oil and gas.
What happens to fossil fuels in the air?
They undergo combustion with oxygen
What are the products of combustion?
Carbon dioxide and water.
What are hydrocarbons?
Molecules that only consist of carbon and hydrogen
