January to March test Flashcards
What is physical change?
No new substances formed
Usually involves appearance change or change of state
Reversible
What can cause physical change?
Physical changes include transitions from one state to another, such as from solid to liquid or liquid to gas. Cutting, bending, dissolving, freezing, boiling, sublimation and melting are some of the processes that create physical changes.
What is chemical change?
One or more new substances formed
Usually involves apperance change
Detectable energy change
Two or more substances (the reactants) react together forming one or more new substances.
Is this experiment reversible?
Test tube- spatula of white copper sulfate powder+water
The solution became warm and change blue in colour
Yes this is a physical cahnge- can be reversed if thw solution is heated
Experiment- is this reversible?
Test tube with copper sulfate and then add iron wool. The solution becomes clear
No , chemical change, not reversible
copper sulphate + iron= copper and iron sulfate
metal + acid=?
salt and hydrogen
Magnesium + hydrochloric acid=
Magnesium chloride and hydrogen
zinc +sulfuric acid=
zinc sulfate + hydrogen
Reactivity series
Metals above hydrogen in the reactivity series will react with acids to make? what
a salt and hydrogen
Metals below hydrogen in the reactivity series do what?
DON’T react with acids. The reaction becomes less and less exciting as you go down the series
What is conservation of mass?
In chemical reactions, the total mass of reactants is equal to the total mass of products. No atoms are made or destroyed
Li
Lithium
What are Exothermic reactions?
An Exothermic reaction is one which GIVES OUT ENERGY to the surroundings- usually heat
Examples of exothermic reactions
Combustion
Neutralisation
Burning match
Magnesium and acid
What are endothermic reactions?
It is a reaction that TAKES IN ENERGY from the surroundings
Examples of endothermic reactions
Thermal decomposition
Photosynthesis
What are fuels?
Granola- energy for humans
Coal-fuel that provides light and thermal energy
What is needed for a fire?
Fire triangle
Heat
Fuel
Oxygen
What does the top number 7 mean and what does the bottom number mean
Fire triangle
Heat, Fuel, oxygen
Word equation for combustion
fuel+oxygen+heat= water + carbon dioxide and heat
Fire triangle
How to test for C02?
limewater reacts with carbon dioxide and turns cloudy
How to test for water?
cobalt chloride paper turns blue to pink
What is thermal decomposition?
Thermal decomposition is when a compound breaks down into 2 or more simple substances when heated
what happens in this example of thermal decomposition?
copper carbonate = ? what
copper oxide and carbon dioxide
CuCO3(s) = CuO (s)+ CO2
what does the s mean?(the substance is a solid)
thermal decomposition of metal carbonates
metal carbonate–>
metal oxide and carbon dioxide
Another exaple of thermal decomposition
silver nitrate–>
silver + nitrogen dioxide + oxygen
Balance this example of thermal decomposition
AgNO3—-> Ag + NO2 +O2
2AgNO3–> 2Ag + 2NO2 + O2
draw a particle diagram of the above on a piece of paper
what is a Precipitation reaction
These are chemical reactions where two solutions reacts together to form an insoluble product.
It starts clear and ends as a cloudy mixture.
a) Silver bromide (s) + Sodium Nitrate
b) Copper Hydroxide (s) + Sodium Nitrate
c) Silver Iodide (s) + Potassium Nitrate
d) Barium Sulphate (s) + Sodium Chloride
