Previous Labs
Did the reaction between the baking soda solution and calcium chloride increase or decrease in temperature?
The temperature increased
What must you have for a successful chemical reaction? (Hint: 2 things)
1) Correct orientation
2) Sufficient energy
What do you need in order for an equation to be balanced?
Equal amounts of molecules in the reactants AND products.
Ex. 6CO2 + 6H2O + heat --> C6H12O6 + 6O2
What is the difference in energy in endothermic and exothermic reactions? (Hint: release/absorb)
Endothermic reactions absorb energy, and exothermic reactions release energy.
Why is it important to balance a chemical equation?
To make sure there's an equal number of atoms of elements on both sides of the reaction to abide with the law of the conservation of mass
Which reacted faster: the whole chalk piece or the crushed up chalk?
Crushed up chalk; more surface area to interact with
What is the only factor in chemical reactions that increases the PERCENTAGE of successful collisions?
Temperature
What can be changed when balancing chemical equations?
The coefficient (the big number BEFORE the chemical)
What is an example of an exothermic reaction?
Many answers:
combustion; respiration; rusting; decomposition
and more!
If I start a chemical reaction and the reactants have a mass of 400g, what will be the mass of the products?
Also 400g!
What kind of reaction do you get with vinegar and baking soda? (Hint: exo or endo)
Endothermic
What are TWO ways that can make chemical reactions happen faster?
Increase of concentration
Increase of temperature
Increase of surface area
Increase of pressure
Is this equation balanced?
2Al + 3FeO --> Al2O3 + 3Fe
Yes
What is an example of an endothermic reaction?
Many examples:
melting ice; photosynthesis; cooking/baking
and more!
True or False:
When you burn something, you are destroying those atoms
False
Burning something doesn't destroy in terms of mass, it transforms the atoms to gases and ashes
What happened to the potassium permanganate when you added the heated oxalic acid compared to the room temperature acid?
The purple changed to clear FASTER than the oxalic acid at room temperature
What does a catalyst do?
Lowers required activation energy for a reaction
Balance the equation!
_Sb + _O2 --> _Sb4O6
4Sb + 3O2 --> 1Sb4O6
How do temperatures change in endothermic AND exothermic reactions?
Endothermic reactions have lower temperatures, and exothermic reactions have higher temperatures.
What is the Law of Conservation of Mass?
Mass is neither created nor destroyed in chemical reactions.
What are two things you could do to increase the concentration of a solution?
Either:
1) Add more solute to the solution
2) Decrease the volume of the solvent
What is a real life example of a way to could increase the reaction rate of a chemical?
Many answers
Too many to list here
Balance the Equation!
2Si2H2 + _O2 --> _SiO2 + _H2O
2Si2H2 + 5O2 --> 4SiO2 + 2H2O
Which type of reaction has more activation energy: exothermic or endothermic reactions?
Endothermic reactions
What is one type of reaction that violates the law of conservation of mass?
Nuclear reactions; mass is converted into energy