Chapter 4 - Changes In Matter Flashcards
What are chemical changes?
When bonds between the atoms of the reactants are broken and new bonds are formed
What is the Law of Conservation of Mass? /3
States that the total mass of reactants is ALWAYS EQUAL to the total mass of products
REACTANTS = PRODUCTS
NO BALANCING JUST ADD AND SUBTRACT
Name 3 Carbon Cycle Chemical Reactions: /3
Combustion
Photosynthesis
Cellular Respiration
What is combustion?
A chemical reaction where:
Fuel + Oxygen —> Carbon Dioxide + Water + Energy
Ex. CH4 +2O2 —> CO2 + 2H2O + energy
(This equation is balanced)
What do you do if you need an ODD number of one element to balance the chemical equation?
Times everything by 2!
Ex. C6H14 + O2 —> CO2 + H2O + energy
2[C6H14 + 19/2 O2 —> 6O2 + 7H2O] + energy
Final answer:
2C6H14 + 19O2 —> 12O2 + 14H2O +energy
What is photosynthesis? /2
Plants use sunlight, water and carbon dioxide to produce glucose and oxygen
Formula:
6CO2 + 6H2O + sunlight —> C6H12O6 + 6O2
What is cellular respiration? /3
Cells (mitochondria) use oxygen and glucose (sugar) to make ATP energy
Releasing carbon dioxide back into the atmosphere
Formula:
6O2 + C6H12O6 —> 6CO2 + 6H20 + ATP energy
What is balancing chemical equations? /2
Consists of placing a coefficient before each reactant and product
The number of atoms of each element on the reactant side is equal to the number of atoms on the product side
What rules must you follow when balancing chemical equations? /4
Coefficients MUST BE WHOLE NUMBERS
Coefficients must be as SMALL as possible
New substances must never be added
Subscripts in chemical MUST NEVER BE CHANGED
What is acid-base neutralization? /3
Chemical change involving the reaction of an acid with a base
Producing salt and water
Formula: Acid + Base ==> Salt + Water
How to execute an acid-base neutralization? /7
Highlight H in the acid and the OH in the base ⬇️ Form your salt by writing the metal from the base and the nonmetal from the acid ⬇️ Write the group number of the metal ⬇️ Subtract the group number of the nonmetal from 8 (8-#) ⬇️ Cross the group numbers ⬇️ Form your H2O ⬇️ Balance the equation if necessary
What 3 elements are needed to start a fire? /3
Fire triangle
Oxidizing agent
Fuel
Ignition temperature
What is an oxidizing agent? /2
Substance that can cause a fuel to react
Oxygen is the most common oxidizing agent on Earth
What is fuel?
Substance that releases a large amount of energy by reacting with an oxidizing agent
Ex. Wood and propane
What is ignition temperature? /2
The minimum temperature of which the energy present is sufficient to start combustion
Can vary from one fuel to another
