chem test - 3/27/24 Flashcards
(37 cards)
What is the Law of Conservation of Mass?
Atoms can only be rearranged in a chemical reaction, not created or destroyed, leading to the conservation of mass where the mass of reactants equals the mass of products, only in a closed system.
What are open systems?
Systems that allow matter to enter or leave, potentially altering the total mass while still adhering to the law of conservation.
What are closed systems?
Systems that do not allow matter to enter or leave, maintaining a constant mass according to the law of conservation, though energy may change forms.
What is a synthesis reaction?
Reactions where smaller molecules combine to form larger molecules, represented by A + B → AB.
What is a decomposition reaction?
Reactions where large molecules break down into elements or smaller molecules, represented by AB → A + B.
What is a single displacement reaction?
Reactions where a single element displaces another element in a compound, represented by Z + AB → ZB + A.
Metals can only replace other metals
What is double displacement reaction?
Reactions where elements exchange places within compounds, represented by AB + BC → BB + AC.
What is a combustion reaction?
Reactions where a fuel reacts rapidly with oxygen, producing oxides and energy, potentially resulting in complete or incomplete combustion.
What is an acid?
Aqueous solutions that produce H+ ions, characterized by sour taste, reactivity with metals, and ability to change colors of indicators.
What is a base?
Aqueous solutions that produce OH- or CO32- ions, characterized by bitter taste, slippery feel, and ability to conduct electricity.
What is the pH scale?
Measure of acidity or basicity on a scale from 0 to 14, where pH less than 7 indicates acidity, 7 indicates neutrality, and greater than 7 indicates basicity.
What are acid-base indicators?
Substances that change color based on the acidity or basicity of a solution, such as litmus paper.
What is neutralization?
Reaction between an acid and a base to form water and an ionic compound, resulting in a pH closer to 7.
What happens in neutralization reactions?
Double displacement reactions where acids and bases react to produce water and a salt.
What are the products in complete combustion?
Hydrocarbon + oxygen → carbon dioxide + water + energy
What are the products in incomplete combustion?
Hydrocarbon + oxygen → carbon dioxide + water + carbon monoxide + carbon + energy
What is the difference between rust and corrosion?
Corrosion: Breakdown of a metal as a result of chemical reactions with its environment.
Rusting: One form of corrosion; the corrosion of metals that contain iron.
What causes rust? What prevents it?
Causes: Corrosion of iron affected by air, water, electrolytes, acidity
Prevention: use corrosion resistant materials, such as plastic or paint, protective coating and galvanizing steel.
Corrosion: How does salt contribute to the condition of the car?
It can affect both the bodies of cars and the metal supports of bridges as salt speeds up the process of corrosion once it begins. Salt can create more rust on cars that have already been corroded.
Corrosion: What have car companies done differently from the past to avoid rusting on bumpers?
They have began to make bumpers out of plastic rather than steel as it doesn’t corrode and is much lighter than steel
Corrosion: How does this strategy benefit the environment?
It can reduce the release of metal pollutants and conserve the resources used in steel production that can be very wasteful and harmful
Corrosion: What is meant by beneficial corrosion and how does this differ from rusting?
Beneficial corrosion happens when metals like aluminum or copper develop protective coatings like aluminum oxide or greenish patina, protecting the metal from further damage. In contrast, rusting is the corrosion of iron, where the rust layer doesn’t protect the metal but continues to degrade it.
What is the optimal pH range for swimming pools?
7.2-7.8
What happens if pH drops below this optimal range?
Water irritates the eyes
