Which Solutions Showed The Greatest Change In Ph Why

How is the pH of a solution related to the H3O+?

pH is the negative log of the H3O+ concentration in molarity units.

relationship between OH and H3O+

inversely related

As H3O+ increases, OH-

decreases

What is a buffer?

solution that resists changes in pH by neutralizing small amounts of acids or bases

If you add acid to water, how will the pH change?

pH will decrease

If you add base to water, how will the pH change?

pH will increase

If you add acid to a buffer, how will the pH change?

pH slightly decreases

If you add base to a buffer, how will the pH change?

pH slightly increases

Which solution(s) showed the greatest change in pH? Why?

The water and NaCl solution; not buffers.

Which solutions(s) showed little or no change in pH? Why?

The high and low pH buffer had the least change; they are buffers which resist changes in pH.

A patient with an acidotic blood pH of 7.3 may be treated with an alkali such as sodium hydrogen carbonate. Why would this treatment raise the pH of the blood?

Sodium hydrogen carbonate is a basic solution which will slightly neutralize the acidic blood back into the normal pH range.

What is neutralization?

H+ions from an acid combine with OH- ions from a base to produce water, H2O

What is a titration?

addition of a specific amount of base to an acidic solution, to neutralize the sample, or vice versa

What is the function of an indicator in a titration?

determine the endpoint of a titration by changing color; the acid has been neutralized by the addition of base.

What is the functional group of an alcohol and a phenol?

The hydroxylgroup, OH-, forms the alcohol and phenol functional group.

Why are some alcohols soluble in water?

alcohols with 4 carbons or less, because the hydroxyl group causes the compound to be overall polar.

If an alcohol solution has a pH of 5, would it be a primary alcohol, a secondary alcohol, a tertiary alcohol, or a phenol?

Phenol because when combined with water phenols make weak acids

Propanal solubility and color

soluble; orange

Compound A forms a red-orange precipitate with Benedict's reagent but does not react with iodoform

aldehyde because it positively reacted with Benedict's reagent

Compound B forms a yellow solid in the iodoform test but does not react with Benedict's reagent.

methyl ketone because it reacted with the Iodoform test

What chemical tests could you use to distinguish between 2-pentanone and 3-pentanone?

Use the Iodoform test because only methyl ketones will positively react.

Almond-flavored cookies

Benzaldehyde

Candies with cinnamon flavor

Cinnamaldehyde

Nail polish remover

Acetone

What does the D in D-glucose mean?

The OH group off the chiral carbon furthest from the carbonyl, is on the right side of the molecule, in the Fischer projection.

What is the bond that links monosaccharides in di-and polysaccharides?

Glycocidic bond

What is the type of glycosidic bond in maltose?

alpha-1,4glycosidic bond

Why does maltose have both alpha and beta forms (anomers)?

Mutarotation allows cyclic compounds to open then close. When the ring closes, randomly rotating adjacent atoms cause the anomers

What is the difference in the structure of amylopectin and amylose?

Amylose = continuous chain of glucose monomers
amylopectin = similar chain but with many smaller branches.

What is the monosaccharide that results from the complete hydrolysis of amylose?

Glucose

What is the difference in the structure of amylose and cellulose?

Amylose glucose monomers are bonded with alpha-1,4 glycosidic bonds whereas cellulose monomers are bonded with beta-1,4 glycosidic bonds.

What happens to glucose or galactose when the Cu+2 in Benedict's reagent is reduced?

glucose or galactose is oxidized into carboxylic acid compounds

Would you expect fructose or glucose to form a red color rapidly with Seliwanoff's reagent?

Fructose. Seliwanoff's reagent readily reacts with ketones

Why don't all the disaccharides undergo fermentation with yeast?

the specific enzymes for lactose or galactose are not present.

How can the iodine test be used to distinguish between amylose and glycogen?

Amylose produces a deep blue/black color while glycogen produces a reddish-purple color.

carbohydrates that are reducing sugars

Glucose, fructose, lactose

which carbohydrates are ketoses?

Fructose and sucrose

which carbohydrates give a positive fermentation test?

Glucose, fructose, and sucrose

which carbohydrates give a blue-black color in the iodine test?

Starch

Produces a reddish-orange solid with Benedict's reagent and a red color with Seliwanoff's reagent in 1 minute

Sucrose

Produces a color change with Benedict's reagent, a light orange color with Seliwanoff's reagent after 5 min, and produces no bubbles during fermentation.

lactose

Produces no color change with Benedict's or Seliwanoff's reagent, but turns a blue-black color with iodine reagent.

starch

How do the results of the Benedict's test indicate that hydrolysis of sucrose and starch occurred?

The solution turned orange revealing a reducing sugar. (glucose -> sucrose + starch)

How do the results of the iodine test indicate that hydrolysis of starch occurred?

The solution turned yellow which revealed starch was no longer present.

What is the functional group in amines?

ammonia, NH3, with hydrocarbon groups replacing one or more of the hydrogen atoms.

What is the functional group in amides?

carboxylic acid bonded to an amine

What products are formed when amides are hydrolyzed? acid hydrolysis

carboxylic acid and an ammonium salt.

What products are formed when amides are hydrolyzed? base hydrolysis

the salt of a carboxylic acid and ammonia or amine

Neo-Synephrine and methamphetamine are what type of amines?

Both are secondary amines.

What type of compound accounts for the "fishy" odor of fish?

amine

Explain why amines are basic.

they accept protons from the N

You have unknowns that are a carboxylic acid, an ester, and an amine. Describe how you would distinguish among them.

litmus paper: carboxylic acid would turn red; amine blue. smell: ester would smell good, amine bad