Unit 2 & 4 Chemistry

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binds the evidence for a chemical reaction in a lab:

Catalyst: a substance that makes a chemical reaction occur faster without itself being consumed in the reaction

Law of Conservation of Mass: The total mass of reactant, must equal the total mass of products

Synthesis: A+B =AB

Decomposition: AB=A+B

Single Displacement: A+BC=AC+B (activity series)

Double Displacement:

AB+CD= AD+BC

Products that produce:

Precipitation: when one of the products are soluble

Produce Gas:

Neutralization: the reaction of an acid and base in which the solutions' PH level is closer to 7. That produces water and an ionic compound

Organic compounds: a molecular compound that contains one or more carbon-carbon bonds and often one or more carbon- hydrogen bonds

Composed of hydrogen and carbons (hydrocarbons)

Examples: Propane, C3H8 and Butane C4H10

Link between combustion, global warming and greenhouse gases:

Common products are carbon dioxide, water and sometimes carbon monoxide. Carbon dioxide is a greenhouse gas that contributes to climate change as does water vapour. Greenhouse gas any of several atmospheric gases (such as water vapour, carbon dioxide, and methane) that allow solar radiation to pass through the atmosphere but absorb infrared radiation emitted by Earth, there by trapping thermal energy and making Earth warmer

Incomplete vs Complete of organic compounds:

Complete Combustion:

CxHy +O2 (g) -- CO2 (g) + H2O (g) + energy

supply is plentiful of oxygen

ideal way to burn a fuel because it releases the most energy from the fuel molecules

produces cleanest soot and hottest flames

blue flames indicates the gas is completely burned as completely as possible and produces the most thermal energy

Incomplete Combustion:

CxHy + O2 (g) -- C(s) + CO2 (g) + H2O + energy

CxHy + O2 (g) -- CO (g) + H2O (g) + energy

mixture of fuel + air= "fuel rich"

lack of oxygen

soot, yellow, and cooler

undesirable except in starting lawn mowers. A cold combustion lawn mower is much easier to start if a fuel-rich mixture enters its engine than if there is less fuel and more air

Problems with Incomplete Combustion:

Automobile engines:

combustion of gasoline

vehicle is idling

idling engine operates below its optimal temperature

a gasoline is burned less completely than when the engine operates at a higher temperature

Inhalation hazard

chemicals in soot are toxic

soot particles are often too small to be filtered by the upper respiratory tact

particles penetrate deep into the lungs and irritate sensitive tissue

respiratory problems

Silent Killer

Carbon monoxide because there's no color, taste, or odor

binds tightly with the hemoglobin in blood

prevents hemoglobin from binding with inhaled oxygen

during rush hour air enough to cause headaches a mild symptoms of poisoning

Acid: compound that produces hydrogen ions when mixed with water

conducts electricity

tastes sour

turns litmus blue to red

neutralizes bases

Base: compound that produced OH- when mixed with H20

conducts electricity

tastes bitter

turns red litmus blue

neutralizes acids

Acidic Oxide : oxide that forms an acidic solution when dissolved in water; a non metallic oxide

Basic oxide: oxide that forms a basic solution when dissolved in water; a metallic oxide

Oxide: a compound composed of oxygen and one other element

Oxides can form when an element reacts with oxygen, often in air

Metal Oxides + Water -- Basic solutions

Non- Metal oxides + Water -- Acidic Solutions

Environmental concerns with acidic solutions formed when non metal oxides react with water:

The reaction of carbon dioxide with water droplets in the atmosphere makes rain naturally mildly acidic. As a result, "normal rain" has a pH of 5.6 rather than 7 which is neutral. Unusually high levels of carbon dioxide in the atmosphere. in addition to climate change- oceans are acidic too. At a certain pH, animals can not make shells at all.

Products between an acid and a hydroxide (neutralization) :

HCl (aq) + NaOH (aq) -- H2O (l) + NaCl (aq)

acid + base -- water + ionic compound

Neutralization with a carbonate compound:

acid + carbonate -- water + carbon dioxide + ionic compound

H2SO4 (aq) + CaCO3 (s) -- H2O (l) + CO2 (g) + CaSO4 (s)

Four Common Neutralization reactions:

Stomach Acid: Digestive fluids have a pH of 1.5 -acidic. Antacids contain hydroxide or carbonate compounds

3HCl (aq) + Al(OH)3 (s) -- AlCl3 (aq) + 3 H2O (l)

Rehabilitating Lakes:

Solutions and Solubility

The unique properties of water is that it dissolves both polar covalent and ionic compounds

The importance of water and the global water crisis: there is only 2.5% fresh water remaining and the rest of Earth's water is about 97.5% which is too salty to consume. In 2010, almost 900 million people lacked safe drinking water and another 2.6 billion lacked basic sanitation. Three of the most important challenges in providing portable water are population growth, increasing global demand for water, and pollution and exploitation.

How global warming might have an impact on the water crisis:

The effect global warming might have on the availability of fresh water is the rate of flow of water from one part of the cycle to another varies considerably. Groundwater can take several years to replace, it is important to acknowledge, at any given time, there is far more stored water on earth in other words "ground water" or stored in icebergs than actually moving through the water cycle. Therefore when global warming occurs these stored fresh water will melt and continue in the cycle and it will take several years to replace the groundwater

Water molecules showing polar covalent bonds and hydrogen bonds. Relate these bonds to properties of water:

high melting & boiling points -- permits water to exist as a liquid at room temperature

Expansion when cooling from 4C to 0C -- causes ice to float, causes water to freeze from the top down allowing life to continue below

High surface tension -- pulls water into round droplets, allows small insects to walk on water

ability to exchange thermal energy with little change in temperature -- absorb a great deal of thermal energy for a small increase in temperature; release energy for small decrease in temperature

inability to mix with non polar compounds -- enables organisms to retain water because of the waterproof coating (ex. wax on leaves), organisms to store non-polar substances (eg. fats, oils)

Define:

Solution: a homogeneous mixture of two or more substances

Homogeneous: uniform mixture and have only one phase

Solute: the substance that dissolves in a solvent

Solvent: the substance that dissolves the solute

Concentration: ratio of the quantity of solute to the quantity of solution or solvent usually quantity of solute per unit volume of solution

Concentration Solution: a solution with a relatively large quantity of solute dissolved per unit volume of solution

Alloy: a solution of two or more metals

Aqueous Solution: a solution in which water is the solvent

Analyze and obtain data from solubility curves:

Concentration Problems using moles

C=n/V

a solid

concentrated solution (dilution):

CcVc = CdVd

Dilutions involve adding more solvent to a solution to decrease the concentration

Volumetric glassware is required to prepare dilutions

Solubility rules: if the product is slightly soluble (s) its a precipitate

A ionic equation: taken apart and write the ions

Net ionic equation: cross out ions from reactants and products (spectator ions)