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Substances, Mixtures, and Solubility

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Substances, Mixtures, and Solubility. What is a solution section 1. Substances are composed of atoms and elements Substance is matter that has the same fixed composition, can’t be broken down by physical processes Physical processes: boiling, changing pressure, cooling, or sorting - PowerPoint PPT Presentation

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Page 1: Substances, Mixtures, and Solubility
Page 2: Substances, Mixtures, and Solubility

Substances are composed of atoms and elements Substance is matter that has the same fixed

composition, can’t be broken down by physical processes

Physical processes: boiling, changing pressure, cooling, or sorting

Chemical process: change the original substance into new substance(burning, chemical reactions, reaction to light)

REVIEW :Atom have specific protons for each element

Page 3: Substances, Mixtures, and Solubility

Two or more elements chemically combined in specific combinations and composition

H2O, NaCl, H2SO4, Water, salt, sulfuric acid

Page 4: Substances, Mixtures, and Solubility

Mixtures are combinations of substances that are not bonded together and can be separated by physical processes (salt water, granite, salt and pepper)

Heterogeneous Mixtures: mixture where substances are not mixed evenly

◦ Areas have different compositions◦ Seeds in watermelon, minerals in granite, cereal in milk

Page 5: Substances, Mixtures, and Solubility

Homogeneous mixtures: contains 2 or more substances that are evenly mixed but are not chemically bonded together

Shampoo, sugar water, Kool-Aid are examples

Solutions is another name for homogeneous mixtures

Page 6: Substances, Mixtures, and Solubility

Solutions form when a solute (salt) dissolves in a solvent (water)

Forming solids from a solution◦Crystallization occurs when cooling or

evaporation takes place and leaves a solid◦Precipitates forms from a chemical reaction that

produces a substance that isn’t soluable in solution and drops out

Page 7: Substances, Mixtures, and Solubility

Liquid solid solutions: solid (solute) dissolves in liquid(solvent) salt in water

Liquid gas solutions: gas is dissolved in a liquid (gas dissolved in water: carbonated water)

Liquid-liquid solutions: both solute and solvent are liquids ( vinegar and water)

Page 8: Substances, Mixtures, and Solubility

Smaller amount of one gas (solute) is dissolved in a larger amount of gas (solvent)

Both solvent and solute are gases◦Example: Our atmosphere contains 78%

Nitrogen and would be the solvent and other gases in atmosphere would be the solute

Page 9: Substances, Mixtures, and Solubility

In solid solutions, the solvent is a solid

Solute can be a gas, liquid, or solid

Solid-solid solution: alloys are mixture of 2 or more metals melted together and mixed (brass, steel)

Page 10: Substances, Mixtures, and Solubility

Water the Universal Solvent

◦Aqueous refers to a solution of where water is the solvent

◦Water can dissolve may different solutes

Page 11: Substances, Mixtures, and Solubility

Molecular Compounds:

◦Water is formed by sharing electrons between 2 atoms of H and 1 atom of Hydrogen

◦Water molecules when combined have areas of electrical charges that attract opposite charges, thus are polar charged

Page 12: Substances, Mixtures, and Solubility
Page 13: Substances, Mixtures, and Solubility

When compounds are formed by gaining or losing electrons to bond elements together

When atoms gain and lose electrons the number of electrons change and give an overall charge on the atoms

Opposite charge atoms attract and hold each other together

Page 14: Substances, Mixtures, and Solubility
Page 15: Substances, Mixtures, and Solubility

Because of the polar charge of water areas of water molecules attract the charged particles of ionic compounds and break them up

(Page 627 figure 8)

Page 16: Substances, Mixtures, and Solubility

Water molecules moves in between sugar molecules and separate them (thus dissolving)

What will dissolve?Like dissolves like

◦Polar solvents dissolve polar solutes (salt and water)

◦Nonpolar solvents dissolves non polar solutes

Page 17: Substances, Mixtures, and Solubility

If you have a polar molecule and nonpolar molecule (unlike polar molecules) they will not dissolve and will not form a solution

Oil is a nonpolar molecule that will not mix with polar water, therefore these two substances will no form a solution

Page 18: Substances, Mixtures, and Solubility

Solubility is a measurement of how much a solute will dissolve in a given amount of solvent

It is described as how much solvent can be dissolved in 100 ml of solvent at a certain temperature

At 25@ C grams dissolved in 100 ml wataer

Potassium chromate

63 g

Barium sulfide .00025 g

Page 19: Substances, Mixtures, and Solubility

Liquid solid solutions: temperature affects how much solutes can be dissolved

Usually an increase in temperature allows more solute to be dissolved◦Notice on chart that NaCl and CaCO3

become less soluble in higher temperatures

Page 20: Substances, Mixtures, and Solubility
Page 21: Substances, Mixtures, and Solubility

Liquid-gas solutions: increase in temperature decrease the solubility of a gas dissolved in it

Carbon dioxide is dissolved under pressure in water in pop cans

◦Opening a warm can of pop vrs a cold can, the gas is released much faster and leaves the solution under warmer conditions faster

Page 22: Substances, Mixtures, and Solubility

A saturated solutions can hold no more solute in solution at a given temperature or pressure

It will fall to bottom of solvent A hot solution can hold more solute than

at lower temperatures and when cooling the hot saturated solution a supersaturated solution may form

Page 23: Substances, Mixtures, and Solubility

Rate of dissolving is sped up by: ◦Increasing temperature◦Crushing the solute◦Stirring the solution

Page 24: Substances, Mixtures, and Solubility

Concentration of a solution tells you how much solute is present compared to the amount of solvent◦It is recorded by using percent of solute is

compared to solvent◦Juices concentration are written by 15%,

20% etc

Page 25: Substances, Mixtures, and Solubility

When a solute is added to water (salt water) and you want to freeze it , a lower temperature is needed (to freeze salt water could be 31℃)

If you want to boil salt water a greater temperature is needed to boil it

Page 26: Substances, Mixtures, and Solubility

Acids: are substances that release positive H+ ions in water called a hydronium ion

When an acid mixes with water, acid dissolves and releases H+ ion

Page 27: Substances, Mixtures, and Solubility

Sour taste

Conduct electricity

Corrosive (break down substances)

React strongly with metals releasing H gas

Page 28: Substances, Mixtures, and Solubility

Vinegar (acetic acid), citric acid, ascorbic acid we are familiar with

H2SO4 (sulfuric acid) ◦ Production of fertilizers, batteries, paint

HCl (hydrochloric acid) ◦ Muratic acid used in pickling that removes impurities from

the surfaces of metals, cleans motar, bricks HNO3 (nitric acid) use in fertilizer, dyes, and plastic

Page 29: Substances, Mixtures, and Solubility

Bases are substances that accept H+ ions and give off to a solution of water with OH- ions

Page 30: Substances, Mixtures, and Solubility

Feels soapy, slippery Taste bitter Corrosives Conduct electricity

Page 31: Substances, Mixtures, and Solubility

Cleaning productsYour blood is basic in solutionNaOH (sodium Hydroxide) is known as

lye and is used to make soap, clean ovens, unclog drains

CaOH (calcium hydroxide) often called lime is put on athletic fields to mark lines

Page 32: Substances, Mixtures, and Solubility

pH is the measure of how acidic or basic a solution is Ranges from 0-14 where neutral pH is at 7 Below 7 covers the range of acid solutions (closer to 0

is more acidic0 Above 7 covers range of basic solutions (closer to 14 is

more basic)

Page 33: Substances, Mixtures, and Solubility
Page 34: Substances, Mixtures, and Solubility

Some acids are helpful (HCl in stomach to digest food however too concentrated HCl will eat away on tissue

If more H+ (hydronium ions) are present the higher the acidic content (lower pH)

Bases with large amounts of OH- ions (hydroxide) have greater concentrations and are more basic (higher pH)

Each number on pH is 10 fold greater or smaller than the number before it:

Comparing ph3 to ph1 is a difference of 2 2 102 means that there is a difference of

100 times more acidic

Page 35: Substances, Mixtures, and Solubility

Indicators are compounds that react with acidic and basic solutions and produce certain colors to indicate their acidity or basicity tendencies

Page 36: Substances, Mixtures, and Solubility

Neutralization is the reaction of an acid with a base

When an acid and a base are combined, they will neutralization each other and the resulting pH will be 7

NaOH + HCl NaCl + H2O Base acid salt water