Chemical reactions Flashcards
In a chemical reaction are there more atoms
In a chemical reaction, atoms are rearranged but the number of atoms don’t change
How can you tell if there is a chemical reaction
Temperature rise, fizzing or bubbles of gas , colour change, smell and sound and flames
Is water and tea a chemical or physical change
Physical because dissolving is not a chemical reaction.
What is ethanoic acid
Vinegar
What is sodium bicarbonate
Baking soda
What does vinegar and baking soda make
Carbon dioxide
What is a physical reaction
They are reactions that do not make new chemicals. Examples are boiling, melting and freezing. It is usually reversible
What is a chemical reaction
Bonds between atoms are broken and made to make new substances
What is a dioxide
A conpound with 2 oxygen atoms
What is a monoxide
A compound with one oxygen element
What is an oxide
An element that reacted with oxygen
Scientific name for burning
Combustion
What is needed for a fire (fire triangle)
Heat, oxygen and a fuel
What is it called when oxygen is added to a reaction
Oxidation
What is it called when oxygen is removed from an equation
Reduction
What type of reaction is combustion
Oxidisation because a fuel had to have reacted with oxygen to release energy.
Scientific name for rust
Iron oxide
What do the letters in brackets mean after a formula (state symbols)
(s) is solid, l for liquid, g for gas and aq for aqueous solution (dissolves in water)
What happens when magnesium reacts with oxygen
It creates a bright light which we can protect our eyes from by using a welding mask
What does a catalyst do
Speed up the rate of reaction
What happens when you leave hydrogen peroxide at room temperature, what type of reaction is it and is it slow or quick
It turns to water and oxygen and it is a decomposition reaction because it breaks down. It is a slow reaction but you can use a catalyst to speed it up
How can you use enzymes in reactions and what type of reactions
Enzymes are natural biological catalysts
What happens to the catalyst when it is added to a reaction
It is not used up or chemically changed (mass is the same)
What is a common use for catalysts
Digestive system and the exhaust system in a car
What is an exothermic reaction
When energy is transferred to the surroundings and usually feels hot
What is an endothermic reaction
When energy is taken in from the surroundings and usually feels cold
Formula for combustion
Fuel + oxygen-> carbon dioxide + water + energy
What gas does a Bunsen Burner use
Methane (CH4)
What is a bad thing about doing combustion practicals in an open and uninsulated area
Not all the heat will go directly where you want it to and it will go to the surroundings
When can we use exothermic and endothermic reactions realistically
Exothermic- hand warmers, fires and respiration
Endothermic- ice packs, melting ice cube (gases have more energy than solids), cooking an egg
What is thermal decomposition and is it exothermic or endothermic
Breaking down a compound into its elements or simpler compounds using a high temperature. It is endothermic.
What insulates reactions
Polystyrene foam cup
What do you call the odd result in a practical
Anomaly or outlier
What are reactants and products in a reaction
Reactants are the substances that react together and products are the substances formed
What words are not written in word equations
Words like powder ,solution or gas
What is the symbol equation for carbonate
CO3
What is oxygen as a symbol in the air
O2 because it is a molecule
What does acid and base make
Salt and water
What do metals and acids make
Salt and hydrogen
What do acids and metal carbonates make
salt+ carbon dioxide + water
What do you call the little numbers next to elements
Subscripts
How to balance an equation
What goes in must go out so the same atoms must be there but they can be rearranged with numbers in front.
What is the Law of Conservation of Mass
During chemical reactions or a change of state, no atoms are created or destroyed. The total mass stays the same.
If a log is burnt, will the ash of it weight the same as the log and oxygen
No because carbon dioxide and oxygen would have went into the atmosphere but if you gathered those gases it would still weigh the same.
Symbol equation for butane
C4H10
What is the only product when hydrogen burns
Water
What is a fuel
A substance which can be burned to release energy
How much reactants and products are in thermal decomposition reactions
One reactant because it is just a compound being heated. There are always 2 or more products because the compound is being broken down
Why does ethanoic acid and sodium bicarbonate set out a candle
It produces carbon dioxide which displaces the oxygen to fuel the fire.
Are combustion reactions reversible
No they are irreversible
Scientific name for fizzing
Effervescence
If a reaction tested alcohols to see which was more efficient in heating to 30 degrees, would you want the alcohol that released the least or most mass
The one that released the least amount of mass would be more efficient because it used less energy but still heated it to the same point.
What is an element
Substance that consists of one type of atom and in the periodic table
What is a compound
A substance made from more than one type of element and they are chemically bonded together
What is a diatomic molecule and name an example
A diatomic molecule is a molecule that has two elements, same or different. An example is oxygen.
What do you call diatomic molecules with the same element
A homonuclear diatomic molecule
What do you call diatomic molecules with different elements
A heteronuclear diatomic element
What does it mean for a metal to be found ‘native’
Pure unreactive form
Why can we not find most metals in their pure form but we can find gold and silver in their pure form
Gold and silver are unreactive metals so they will be displaced if other substances come into contact with it and left in pure form. However, if reactive metals came into contact with other substances, they would displace another metal and become a compound.
What happens to cobalt chloride paper/ anhydrous copper sulfate if exposed to water
The paper will turn pink and the sulfate will go from white to blue
What hazard is represented by the symbol of a chemical in a test tube being poured on a hand
Corrosion
What hazard is represented by the symbol of a fish and tree and explain it
Environment hazard like pouring chemicals down the sink can harm marine life (water pollution)
What hazard is represented by the symbol of a circle in half with arrows pointing outwards
Explosive
What hazard is represented by the symbol of a person with arrows pointing out a circle in the centre of their chest
Health hazard
What safety precautions can you take
Wearying safety goggles, wearing gloves, wearing a lab coat and tying back hair and tucking away loose clothing
What name is given to a reaction where hydrogen ions react with hydrogen ions to make water
Neutralisation
Oxidation is the … of electrons. Reduction is the … of electrons
First gap is loss and second is gain
There are metals in a room and oxygen so why aren’t they reacting
The metals are already bound to something and not pure metals or you need catalysts
What is a metal carbonate
A compound that contains metal, carbon and oxygen
How do you stop a fire
Remove a side of the fire triangle
What extinguisher to use on a wood fire and why
A water extinguisher because it removes the heat aspect by extreme cooling
What extinguisher to use on an electrical fire and why
A CO2 extinguisher because it removes the oxygen aspect by displacing it
What extinguisher (or alternative) to use on a chip pan fire and why
A wet chemical extinguisher because it removes the heat aspect.An alternative could be a fire blanket but not water as the fire will spit it out.
What extinguisher to use on a car fire and why
An ABC dry powder extinguisher because it removes the oxygen aspect by forming a barrier between the fuel and oxygen source.
What do foam extinguishers do
They work by a build up of foam on the surface, meaning oxygen can’t enter and it cools the fuel
If a candle was lit in a big or small jar which jar would take longest for the candle to go out and why
It would take longest for the bigger jar’s candle to go out because it had the most oxygen, one of the sides of the fire triangle
What does hydrogen do when near a burning splint
Make a pop sound
What is the thermal energy store in a fire
Flame
