SCI Unit 3
a) 10^-9 (14-5) b) 9 c) basic (states OH in problem)
A water solution at 25°C has [OH−] = 10−5 M. a) What is [H3O+]? b) What's the pH
hydronium ion
H3O+
HF + NaOH -> NaF (sodium fluoride, a salt) + H2O
Hydrogen fluoride (HF), an acid, reacts w/ sodium hydroxide to produce a salt that's used in toothpaste to help prevent tooth decay. What's the name of the salt that forms in this reaction?
a) salt, calcium carbonate, antacids b) acid, acetic acid, vinegar c) acid, sulfuric acid, car batteries d) acid, hydrochloric acid, certain toilet cleaners e) base, sodium bicarbonate, baking soda f) acid, boric acid, certain eye washes g) base, magnesium hydroxide, milk of magnesia h) salt, magnesium sulfate, epsom salts i) salt, potassium iodide, iodized salt j) base, sodium hydroxide, certain oven and drain cleaners k) base, ammonia, household ammonia
Identify each of the following compounds as an acid, a base, or a salt; give its chemical name; and name a consumer product in which it occurs: a) CaCO3 b) CH3CO2H c) H2SO4 d) HCl e) NaHCO3 f) H3BO3 g) Mg(OH)2 h) MgSO4 i) Kl j) NaOH k) NH3
protons or hydronium ions H3O+; OH-, hydroxide ions
In aqueous solutions, acids yield ---- and bases yield ----
a) sulfuric acid, H2SO4 b) potassium hydroxide, KOH c) ascorbic acid, C6H8O6 d) sodium bicarbonate, NaHCO3 e) carbonic acid, H2CO3 f) acetic acid, CH3CO2H g) citric acid, C6H8O7 h) sodium hydroxide, NaOH
Indicate the acid or base associated w/ each of the following everyday items: a) car batteries b) alkaline batteries c) vitamin C d) baking soda e) seltzer water f) vinegar g) oranges h) typical oven cleaners
no, when an acid donates a proton, a base accepts it, so both acid and base must be present
Can a substance act as an acid in the absence of a base?
1 x 10 ^-3 M
The pH of a typical soft drink is about 3. What is the value of [H3O+] for a soft drink?
the carboxyl group, -CO2H
What characteristic of molecular structure is common to all carboxylic acids
salt
What chemical species is always produced in a neutralization reaction?
red; blue; blue
What color would you expect litmus paper to turn when exposed to the following? a) vinegar b) a slurry of baking soda in water c) household ammonia
a) blue b) red c) blue d) red e) red
What color- red or blue- would you expect each of the following liquids to produce when added to litmus: a) milk of magnesia b) wine c) seawater d) a soft drink e) tomato juice
it means that water can act as an acid or a base
What do we mean when we say that water is amphoteric
carbon dioxide
What gas is formed when you drop an Alka-Seltzer tablet into water?
a positively charged particle consisting of two protons and two neutrons (why atomic # is 2 bc atomic # = p+ and why mass # is 4 bc 2 protons + 2 neutrons
What is an α particle; what's its charge
a decrease in the pH of the oceans due to the absorption of atmospheric CO2
What is ocean acidification
6 (bc pH + pOH = 14 in a water solution at 25 degrees C; you know the ph is 8 bc you just reverse the sign of the exponent from the concentration and 14 -8 = 6)
What is the pH of a solution at 25°C when the hydroxide ion concentration is 10^−8 M?
7
What is the pH of pure water at a temperature of 25°C?
the carboxyl group, -CO2H
What structural feature is common to all carboxylic acids?
sulfur dioxide (SO2) and nitrogen oxides (NOx; THINK: NO) -(which then produces sulfuric and nitric acid)
What two gaseous emissions are primarily responsible for acid rain?
a neutralization reaction, CH 3 - CO2H, is acetic acid, NaOH is sodium hydroxide, a base Na+CH3 -CO2-, is sodium acetate, a salt
What type of reaction is the following equation? Identify each compound (other than water) as an acid, a base, or a salt: CH3CO2H + NaOH -> NA+CH3CO2 + H2O
a chemical species that has an odd number of electrons
What's a free radical
a mass of fissionable material large enough to ensure that released neutrons are absorbed by other fissionable nuclei, thereby sustaining a nuclear chain reaction
What's critical mass
a unit of ionizing radiation representing an equivalent dose to humans, regardless of the type of radiation (think: RI)
What's rem?
a hydrogen ion, H+, is a proton; a hydronium ion, H3O+ is formed when a proton bonds to a molecule of water
What's the difference between a hydrogen ion and a hydronium ion
-a weak acid, such as acetic, boric, or carbonic acid, ionizes partially in water -a strong acid, such as hydrochloric, sulfuric, and nitric acid, ionizes completely in water
What's the difference between a weak acid and a strong acid? Give an ex. of each
litmus paper
an absorbent paper strip containing a natural dye that turns red in acid solution and blue in basic solution
strong acid
an acid that ionizes completely in aqueous solution to form an equivalent amount of hydronium ions
weak acid
an acid that ionizes partially in water
weak acid
an acid that is only slightly ionized in aqueous solution; it releases few hydrogen ions in a solution
salt (in common usage, salt or table salt refers specifically to sodium chloride -NaCl)
an ionic compound produced by the reaction of an acid and a base
salt (in common usage, salt or table salt refers specifically to sodium chloride (NaCl)
an ionic compound that can be produced by the reaction of an acid and a base;
decreases
as pH increases, the hydronium ion concentration ------
gamma (γ) radiation
bc of their high energies (even greater than the energies of X-rays) and their ability to penetrate deeply into matter, they can cause considerable biological harm
yes, ex: our pancreas produces a digestive fluid rich in sodium bicarbonate, a base and this fluid enters our small intestines, where it neutralizes stomach acids carried by foods as they exit the stomach and enter the intestines
does neutralization take place in our bodies
antacid
medication that neutralizes acid that's already been made
ionizing radiation
radiation (such as α, β, γ, x and γcosmic rays) capable of ionizing atoms or molecules in its path
positron emitters (some of which are used in medical imaging; an important class of radiotraces, used in positron emission tomography known more commonly as PET)
radioisotopes that decay w/ positron emission
acid rain
rain w/ a pH lower than 5.6, typically due to sulfuric and nitric acid contamination
penetrating power
the ability of ionizing radiation to penetrate matter
hydroxide ion
the anion OH- which is produced when bases dissolve in water
hydroxide ion
the anion OH-, produced when bases dissolve in water
hydronium ion
the cation H3O+ which is produced when acids release hydrogen ions (H+) in water
radioactivity
the emission of radiation by the spontaneous decay of an unstable atomic nucleus
binding energy (the cement that holds the nucleus together which comes from the conversion into energy of a very small fraction of the masses of the protons and neutrons that compose the atom)
the energy required to hold the protons and neutrons together in the nucleus of an atom
half-life
the length of time it takes for 1/2 of a given quantity of a radioactive isotope to decay; every radioisotope has its own characteristic half-life
nuclide
the nucleus of an isotope, characterized by the number of protons and neutrons it contains
common acids (although not all compounds w/ hydrogen atoms are necessarily acidic; ex: HCl (hydrochloric acid) and CH3CO2H (acetic acid) are acids while NH3, ammonia isn't an acid)
these have one or more hydrogen atoms
hydronium ion
this cation is produced when acids release hydrogen ions (H+) in water
gamma (γ) radiation
very high-energy (short wavelength) radiation emitted by excited-state nuclei
alpha particles (Beta and gamma rays have progressively weaker ionizing alpha rays but they penetrate matter further)
w/ their relatively large masses (4 atomic mass units) and 2 positive charges, have enough mass and charge to do considerable damage to whatever atoms and molecules they strike; they have considerable ionizing power, but, as we've seen, they have little penetrating power; however, they do a considerable amount of damage in the short distances they travel
it liberates the hydrogen gas
what does a magnesium strip do in an acid solution
strong acids and strong bases ionize completely in water, whereas weak acids and weak bases ionize partially and reversibly in water
what governs the strength of an acid or base
the extent to which the acid ionizes and on the concentration of the acid -(a more concentrated solution of a given acid is more acidic than a less concentrated solution of the same acid)
what is the acidity of a solution (the concentration of the hydronium ion)
water
The Arrhenius definitions of acids and bases assume the presence of what substance
more; doesn't
The Brønsted-Lowry definition of acids and bases considered to be ----- general than that proposed by Arrhenius bc it ---- the presence of water as solvent
8 x 10^-3 M
Suppose you have a solution of HCl in water that has a hydronium ion concentration of [H3O+] = 0.008 M. Express this value in exponential notation.
yes; no; no
Acids and bases react w/ each other to produce neutral solutions. Could you obtain a neutral solution by mixing, in the proper proportions: a) vinegar and sodium bicarbonate b) the juice of sour pickles and carbonated water c) seawater and milk of magnesia
basic; acidic; acidic
Are each of the following substances neutral, acidic, or basic? a) eggs b) rain c) diet Coke
increases 10 fold; increases 100 fold; increases 1000 fold
By what factor does the hydronium ion concentration change if we decrease pH by... a) one unit? b) two units? c) three units?
a salt is an ionic compound that can be produced by the reaction of an acid and a base
Define a salt
acid; base; NH4+ and HNO3-
For each of the following reactions, identify the acid and base and then indicate the products. HNO3 + NH3 -> ? a) HNO3 b) NH3 c) state products
base; acid; Lil and H2O
For each of the following reactions, identify the acid and base and then indicate the products: LiOH + Hl -> ? a) LiOH b) Hl c) state products
a) H3O+ = 10^-7; OH- = 10^ -7 b) H3O+ = 10 ^-3; OH- = 10^ -11 c) H3O+ = 10^-11; OH- = 10^-3
For each of these three examples, show that [H3O+] × [OH−] = 10−14. Enter [H3O+] at first, then [OH−]: a) pH = 7 b) pH = 3 c) pH = 11
NH3 (ammonia is the only base, the rest are acids)
For the following set, pick the compound that doesn't belong: a) HCL b) CH3CO2H c) H2CO3 d) NH3 e) H2SO4
nitric acid (the only compound in the list that isn't a carboxylic acid)
For the following set, pick the compound that doesn't belong: a) acetic acid b) citric acid c) nitric acid d) oxalic acid e) lactic acid
sodium hydroxide (the only compound that isn't a weak acid or base)
For the following set, pick the compound that doesn't belong: a) boric acid b) sodium bicarbonate c) carbonic acid d) ammonia e) sodium hydroxide
8 (hydronium = acids, hydroxide = bases)
Fresh eggs typically have a hydronium ion concentration of about 0.00000001 M. What is the typical pH of a fresh egg?
oxalic acid, citric acid (also: acetic acid)
Give the names of two carboxylic acids that can be found in foods
mass defect (original atomic mass is found to be less than the sum of individual masses of its constituent particles- this is bc energy is removed during the formation of the nucleus; mass defect is the mass missing in the resulting nucleus and represents the energy released during the formation of the nucleus)
Proton and neutron are the constituent particles of nucleus. But the mass of a nucleus is found to differ from the sum of masses of proton and neutron. This difference in mass is known as...
a hydronium ion, H3O+
Suppose the nucleus of a hydrogen atom enters a quantity of water; what's produced by the interaction of the hydrogen nucleus w/ a water molecule
a) .00001 b) .00002 mol H3O+
Suppose you have a solution in which [H3O+] = 1 × 10−5 M. a) Express this value in decimal notation b) How many moles of hydronium ions are in 2 liters of this solution?
acidic
Which category describes most foods; acidic, neutral, or basic
a) 0.01 M HCl b) 0.01 M acetic acid c) 0.01 M nitric acid
Which member (if either) of each of the following pairs of solutions would you expect to show a higher hydronium ion concentration? a) 0.01 M HCl or 0.0001 M HCl b) 0.01 M acetic acid or 0.0001 M acetic acid c) 0.01 M nitric acid (HNO3) or 0.01 M acetic acid
-the concentrations are constant bc water is in dynamic equilibrium w/ the ions it forms; the concentrations are equal to each other bc each ionization event produce one hydronium and one hydroxide ion
Why are the concentrations of hydronium and hydroxide ions in purewater constant (at a given temp) and equal to each other?
-antacids provide enough base to just neutralize excess stomach acid; the stomach needs to maintain acidity for normal functioning
Why does an antacid neutralize some, but not all, stomach acid
it's less in the case of the acetic acid solution bc acetic acid only partially ionizes; it's a weak acid
Why is the hydronium ion concentration different in the case of a 0.04 M solution of acetic acid than it is in a 0.04 M solution of sulfuric acid?
weak base
a base that ionizes partially in water
strong base
a base the dissociates completely in water to form an equivalent amount of hydroxide ions
carboxylic acid
a carbon-bearing acid characterized by the presence of the carboxyl group, -CO2H
base (think 'b' for base and blue)
a chemical compound that turns litmus paper blue and reacts w/ acids to form salts
acid
a chemical compound that turns litmus paper red and reacts w/ bases to form salts
buffer
a combination of a weak acid and its conjugate base that resists changes in pH
β particle (the discharge of this results in β radiation or β decay)
a high-speed electron emitted during (β) radioactive decay
pH
a measure of acidity, defined as the negative logarithm of the hydronium ion concentration
ionizing power
a measure of how efficiently ionizing radiation causes ionization as it penetrates matter
positron
a positively charged analog of an electron; a particle indistinguishable from an electron except that it carries a positive charge
isotopic enrichment
a process of increasing the abundance of a desired isotope in a mixture by removing the undesired isotope
neutralization
a reaction between an acid and a base to produce a salt and oftentimes water
neutralization (ex: a simple acid-base neutralization occurs when HCl reacts w/ NaOH; neutralization reactions an produce a variety of other salts such as potassium iodide and magnesium sulfate)
a reaction between an acid and a base to produce a salt and water
nuclear fission
a reaction that splits a relatively massive nucleus into two or more sizable fragments, *releasing* energy in the process
dynamic equilibrium
a state in which the rate of a forward reaction (such as ionization) equals the rate of the reverse reaction (such as recombination) so that the concentrations of all chemical species remain constant
dynamic equilibrium
a state in which the rate of a forward reaction (such as ionization) equals the rate of the reverse reaction (such as recombination), such that the concentrations of all chemical species remains constant
amphoteric (ex: water)
a substance that can act as both an acid and a base
radiocarbon dating
a technique based on the characteristic rate of carbon-14 for determining the age of an artifact of biological origin
a) carbonic acid b) sulfuric and nitric acids
a) What acid makes rainwater normally acidic? b) What acids give rise to acid rain?
amphoteric
able to act as either an acid or a base
they're ionic compounds containing the hydroxide ion (OH-) or carbonate ion (CO3^-2) (ex: sodium hydroxide, NaOH and calcium carbonate, CaCO3)
how do we define a basic compound- what does it contain
background radiation
ionizing radiation emanating from within us as well as from our environment and outer space
