Objective 1: Understanding Solutions
1. What are the characteristics of solutions, colloids, and suspensions? A solution is something dissolved in something else. By dissolved i mean it needs to have some particles ionized a solid you place in water that dissociates (ions split apart from each other) makes a solution a good solution you can make in your kitchen is a salt-water solution, Put some regular table salt in a glass and stir it and you will notice the salt "disappears" what happens is the sodium ions and the chloride Ions separate and 'hide' between water molecules. Some colloids are translucent because of the Tyndall effect, which is the scattering of light by particles in the colloid. Other colloids may be opaque or have a slight color. Suspensions are pushed down to the bottom/do not dissolve, they can be filtered, light does not pass, and heterogeneous.
2. What happens to the particles of a solute when a solution forms? When a solution forms, particles of the solute leave each.
3. How do solutes affect the freezing point and boiling point of a solvent? The addition of solutes to a nonvolatile solvent to a volatile solution causes an a boiling point elevation and a melting point depression, while also influencing osmotic pressures. These properties can be attributed to the solutes effects on the chemical potentials of the gaseous, liquid and solid phases. It can be generally assumed that solutes do not crystallize out with the solvent during freezing as the solute cannot be easily integrated into the solvent crystal structure. Furthermore, gaseous chemical potential remains unaffected by the solute as the solute does not enter the gas phase (and subsequently the gas remains pure) thereby not influencing gaseous chemical potential (despite decreasing gas pressure). Therefore, it can be seen that chemical potentials of the liquid phase are affected by solute presence. As the vapour pressure above solution is decreased through solute addition, the liquid-gas coexistence phase is present at a higher temperature than for a pure solvent (eliciting a boiling point elevation). Furthermore, as crystal formation is hindered in the solvent (by solute) melting point depression occurs.
4. Suppose you mix food coloring in water to make it blue. Have you made a solution or solution or a suspension? Explain. It would be a solution because it dissolved in the water obviously turning it blue. water dissolves so many solutions that it is often called the "universal solvent."
5. What effects do solutes have on a solvent’s freezing and boiling points? They usually lower freezing points, think antifreeze. And salt water freezes at a lower temp than fresh, that is why they put salt on ice. And they raise boiling points, think salt in water when making spaghetti. Or, again antifreeze.
Objective 2: Concentration and Solubility
1. How is a concentration measured? Concentration is the measure of how much of a given substance there is mixed with another substance.
2. Why is solubility useful in identifying substances? You can identify a substance by its solubility because it is a characteristic property of matter.
3. What factors affect the solubility of a substance? Temperature, pressure, and type of solvent.
4. How does temperature affect the solubility of most solids? Heat is required to break the bonds holding molecules together. solubility is dependant on temperature.
5. How can solubility help you identify a substance? Its because it is a characteristic property of matter.
Objective 3: Describing Acids and Bases
1. What are four properties of acids? Strong or concentrated acids often produce a stinging feeling on mucous membranes
React to indicators as follows: turn blue litmus and methyl orange red, do not change the color of phenolphthalein.
2. What are four properties of bases? Conducts electricity, bitter tasting, reacts with acids to neutralize its properties, feel slippery on the skin.
3. How can you use litmus paper to distinguish an acid from a base? Depends on the paper. All litmus paper is designed to work on different pH ranges. however, most liquid acids used turn blue litmus paper pink. Acid won't affect red litmus. Bases, however, turn red litmus paper blue, and does not affect blue litmus.
4. How might you tell if a food contains an acid as one of its ingredients? You would need to do the litmus test. The strip will indicate if it has any acids or is more neutral.
5. Why is it wise to wear gloves when spreading fertilizer in a garden? Straight fertilizers are usually salts so they can dry out your skin and cause pain in cuts.
However, most of the more expensive brands are "perilled" ..wrapped in soluble little bubbles and are less likely to harm a bare hand. OTOH, some fertilizers, perilled and not, have weed killers in the blend that can be absorbed through the skin. Wearing gloves is a sensible precaution as is eye protection and a dust protector over the mouth, although none of these are mandatory.
Objective 4: Acids and Bases in Solution
1. Which ion is found in acids? H+
2. Which kinds of ions do acids and bases form in water? When acids are added to water, they lose a proton (hydrogen ion). Contrary to popular belief, this proton does not simply exist on its own. Instead, it is bonded to another water molecule, forming a hydronium ion, H3O+. There probably is not a base equivalent as ucenigma has noted. H3O+ exists because you have a bare proton in the presence of molecules containing oxygen, each with 2 pair of unshared electrons in its orbitals. However, with a negative hydroxide ion, they would not be attracted.
3. What ions will the acid HNO3 form when dissolved in water? HNO3 breaks up to H+ NO3- in solution, and is an acid
4. What does a substance’s pH tell you? The amount of H+ ions.
5. If a solution has a pH of 6, would the solution contain more or fewer hydrogen ons (H+) than an equal volume of solution with a pH of 3? No it would not.
Objective 5: Digestion and pH
1. What are the two parts of digestion?
2. How do those two parts differ?
3. People who have lost most of their teeth may have trouble chewing their food. How does this affect their digestive process?
4. What is the pH in your mouth? Stomach? Small intestine?
5. Why are pH variations in different parts of the digestive system important to the process of digestion?
Objective 6: Key Terms
Define:
1. Acid is any of a class of substances whose aqueous solutions are characterized by a sour taste, the ability to turn blue litmus red, and the ability to react with bases and certain metals to form salts.
2. Neutralization is a reaction between acid and base which neutralizes both and results in the formation of water plus a salt.
3. indicator is a substance that indicates the degree of acidity or basically of a solution through characteristic color changes.
4. corrosive is a substance, especially a strong acid; capable of destroying or eating away by chemical action.
5. hydroxide ion is A chemical compound containing the hydroxyl group, especially one that releases a hydroxyl group when dissolved.
