CHM1020 Exam 4 Study
T/F a nuclear equation is balanced in the same way as any other chemical equation
false (in chemical equation the atoms must balance. in nuclear equation the atoms do not balance, since one nucleus is converted into another. Instead the protons and neutrons will balance)
most electronegative
general direction least to most on periodic table ↗
Acids produce this in water
hydronium ion
Which of the following compounds are soluble in water?
- Pb(NO3)2 (nitrates (NO3-) are always soluble) - NH4Cl (NH4+ salts are always soluble)
Match each H+ concentration to its corresponding OH- concentration in aqueous solution
- [H+]= 1x10^-10 : [OH-]= 1x10^-4 - [H+]= 1x10^-7 : [OH-]= 1x10^-7 - [H+]= 3x10^-7 : [OH-]= 3x10^-8 ([H+] x [OH-]= 1x10^14) - [H+]= 5x10^-2 : [OH-]= 2x10^-13 ([H+] x [OH-]= 1x10^14)
Which techniques are used to desalinate water?
- distillation - reverse osmosis
Which of the following options correctly compare the effect of acid precipitation on lakes in different geological surroundings?
- lakes in granite areas tend to have lower pH values than lakes in limestone regions - lakes in limestone regions have a higher acid-neutralizing capacity
Match the symbols correctly to describe the uneven charge distribution in any polar covalent bond.
δ+; marks the atom with the LOWER electronegativity δ-; marks the atom with the HIGHER electronegativity
hydrogen bonding is an example of a ____ force
intermolecular
If a solute dissolves in water to form a solution that does not conduct an electric current, the solute is a(n) ____
nonelectrolyte
BOD is a measure of the amount of dissolved ____ microorganisms use up as they decompose organic wastes found in water
oxygen (BOD is acronym for biological oxygen demand)
the rate at which energy is produced is referred to as ____, which is typically measured in kilo- or mega- ____.
power; watts
Which of the following options correctly describes how an acid produces ions when dissolved in water?
the strong attraction between H2O molecules and the H of the acid causes the acid molecule to break apart
The levels of which of the following species will have an impact on the formation of the CaCO3 shells of marine organisms such as coral?
- CO2-/3 - HCO-/3 - CO2
Which of the following species are formed when HNO3 and NaOH react in aqueous solution?
- Na+ (aq) (NaOH dissociates to form Na+ and OH-. The Na+ ions remain in solution since NaNO3 is soluble in water) - H2O (l)
Which of the following options correctly describe spent nuclear fuel?
- Spent nuclear fuel is classified as high-level radioactive waste - Spent nuclear fuel contains may different radioactive isotopes
Which of the following statements correctly describe the half-life of a radioactive nuclide? Select all that apply
- The half-life is the time taken for the level of radioactivity in a sample to drop to half of its initial value - The half-life for a given radioisotope is the same under all reaction conditions - The time taken for half the nuclei to decay is the same regardless of the initial number of nuclei present
Which of the following options correctly describe the water cycle?
- a drop of water in the ocean could one day end up in a lake - climate can affect the water cycle
electronegativity
-- D) is a measure of an atom's attraction for an electron in a chemical bond A) is the same for all of the elements in a family or group B) is the total negative charge on a polyatomic anion. C) decreases from left to right across a period on the periodic table D) is a measure of an atom's attraction for an electron in a chemical bond
Bottled water consumption was reported to be 29.0 gallons per person in the US in 2007. This is equivalent to how many 0.500-L bottles per day? Round up to the nearest whole bottle
1 bottle/day Step 1: 29 gal in year in L? 29 gal/1yr x 3.78 L/1gal = 1.10 x 10^2 L/yr Step 2: L per day? 1.10x10^2 L/1yr x 1 yr/365 days = 0.300 L/day Step 3: Equivalent to how many .500 L/day? .300 L/1 day x 2 bottles/1L = 1 bottle/day
Give the chemical name for the aqueous solution that forms when the gas HF dissolves in water
Hydrofluoric acid
A solution is acidic if ___
[H+] > [OH-]
match each type of radiation correctly to the resulting change in atomic number
a emission- atomic number decrease by 2 B emission- atomic number increases by 1 Y radiation- atomic number remains unchanged
a substance that releases H+ ions in water is called a(n) ____
acid
The capacity of a lake or other body of water to resist a decrease in pH when exposed to acidic precipitation or runoff is called its ____ capacity
acid-neutralizing
A(n) ____ solution is one in which water is the solvent
aqueous
Naturally occurring underground reservoirs containing fresh water are called ____
aquifers
A substance that released OH- ions in water is called a(n) ____
base
An aqueous solution of ____ acid is often used as the primary coolant in nuclear reactors. This solution absorbs heat and also acts as a ____ by slowing down neutrons
boric; moderator
Aqueous solutions of hydrochloric acid and barium hydroxide can neutralize each other to produce a compound that is soluble in water. Give the chemical formula of the anion and cation found in this compound
cation: Ba^2+ anion: Cl- Step 1: neutralization reaction is a chemical reaction in which the hydrogen ions from an acid combine with the hydroxide ions from a base to form water molecules
Both ozone (O3) and UV radiation have been used as alternative disinfectants to chlorine-containing compounds in the water treatment process. However, ____ must be added to water after either of these treatment methods in order to protect the water after it leaves the treatment site
chlorine
The ____ of a substance is its mass per unit volume. The value for water is 1 g/cm3
density
Water has some unique properties such as its anomalously high boiling point and its very low density in the solid state. The difference between water and H2S is that water can form ____ between its molecules, whereas H2S cannot
hydrogen bonds
All ____ bonds are much weaker than ____ bonds
hydrogen bonds; covalent (hydrogen bonds have only about one tenth of the strength of a covalent bond)
One water molecule can hydrogen bond to four other water molecules giving its solid phase hexagonal channels. As a result, the molecules in the solid state are ____ closely packed than in the liquid state and solid water is therefore ____ dense than liquid water
less; less
Which of the following solvents in the most environmentally friendly?
liquid carbon dioxide
ppm
mass (g) of solute/ 1x10^6 g solution
In a(n) _____ bond electrons are not shared equally, but are closer to the more electronegative atom
polar covalent
An acid releases H+ ions in water. The H+ ion is a hydrogen atom that has lost its electron, and is therefore often referred to as a(n) ____
proton
stable isotopes differ form radioactive isotopes in their neutron-to-____ ratio
proton
a(n) ____ is a material that has a limited capacity to conduct an electric current
semiconductor
match each state of matter with the correct descriptions of its behavior
solids: - fixed shape and volume - particles close together and organized Liquids: - takes the shape of the container - particles move fluidity but are still attracted gas: - particles far apart with few attractions - volume determined by container - takes the shape of the container
A _____ is a homogeneous mixture of a solvent and one or more solutes
solution
An acid that dissociates completely in aqueous solution is called a(n) ____ acid
strong
A(n) ____, also sometimes called a wetting agent, is a compound that helps polar and nonpolar compounds mix
surfactant
The abbreviation STP indicates standard ____ and ____
temperature; pressure
solute
the minority component of the solution
A solution with a pH= 3.0 has ____ the hydrogen concentration of a solution with a pH= 4.0
10 times
When 227/89 Ac produced a beta particle, which new isotope is produced?
227/90 Th 227/89 Ac -> 227/90 Th + 0/-1 e
Which of the following is a characteristic reaction of acids?
Acids react with carbonates to produce carbon dioxide
nitrite
NO2-
T/F the electrical energy generated by a nuclear power station is no different from the electrical energy produced by a fossil fuel plant
True (both types of plants produce electricity by transferring energy from a reaction to a steam generator, which runs a steam turbine to produce electrical energy)
Neutralization is the reaction between a(n) ____ and a(n) ____
acid; base
Is a solution with [H+] = 1x10^-6 M acidic, basic or neutral?
acidic
nonpolar bonds
between same elements
during nuclear fission, the mass of the products is slightly ____ than the mass of the reactants. This mass difference accounts for the energy ____ by the reaction
lower; released
When hydrogen is covalently bonded to ____, oxygen, or fluorine there will be an attraction between such a hydrogen and a lone pair of electrons on one of the aforementioned atoms on an adjacent molecule or in a different part of the same molecule. This attraction is called a(n) ____ bond and it is the strongest type of intermolecular force
nitrogen; hydrogen
Which of the following household substance is NOT acidic?
oven cleaner
Boron and gallium doped silicon semiconductors may function as ___ semiconductors
p-type
select the two types of semiconductors from the following list
p-type; n-type (n-type have abundance of electrons and p-type have a deficit)
Which of the following options correctly describes the changes that occur when a polar covalent substance such as glucose (C6H12O6) dissolves in water?
the polar glucose molecules are attracted to the polar water molecules, resulting in a solution
Why does an aqueous solution of an ionic substance conduct an electric current?
the solution contains ions that are free to move
What is the pH of a 0.001 M HNO3 (a strong acid) solution?
-- D) 3 A) 1 B) .001 C) 11 D) 3
The half-life of carbon-14 is 5,730 years. If you started with 100.0 g of carbon-14, how much would remain after 4 half-lives?
-- D) 6.25 g A) 57.3 g B) 12.5 g C) 25.0 g D) 6.25 g
All isotopes of an element with an atomic number greater than ___ are radioactive.
-- D) 83 A) 84 B) 82 C) 100 D) 83
What metal is used to dope an n-type semiconductor?
-- D) Arsenic A) Cadmium B) Gallium C) Silicon D) Arsenic Silicon can't be doped with itself and only one of these has one more electron than silicon.
hypochlorite
ClO-
Bicarbonate
HCO3-
molarity (m)
mol solute/L solution
NaHCO3 can be used to neutralize hydrogen ion, H+. If NaHCO3 can be purchased at a cost of $9.90/kg, how much will it cost to neutralize 1.0 mole of H+?
$0.83 step 1: balance equation step 2: 1.0 mol NaHCO3 x 84.0g/mol x $9.90/kg x 1kg/1000g = $0.83 (mol x molar mass x cost x 1/1000)
Sort the elements below by the charge they will bear as ions
+2: - Ca - Ba - Cd - Zn - Sr +1: - Rb - Cs - K - Ag -1: - F - Br - Cl -2: - O - S
Which unit is commonly used by utilities to measure the amount of electrical energy consumed?
-- D) kWh A) MW B) W C) J D) kWh
match each marked component of a nuclear power plant with the description
A- control rods B- fuel rods C- primary coolant D- steam generator E- reactor vessel
Rank the atoms below in order of increasing electronegativity
Li - C - O - F
Give the chemical name for H3PO4.
Phosphoric acid
sulfite
SO2-/3
sulfate
SO2-/4
percent (%)
amount of solute/ amount of solution x 100
a reaction that is self-sustaining because of the reaction products becomes a reactant is called a(n) ____ reaction
chain
All of the compounds listed below will dissolve in water. With some of them, the resulting solution will conduct electricity(?) and some will not. Sort the compounds by whether or not they are electrolytes
electrolytes: - LiNO3 - CaCl2 - K2CO3 - K3PO4 non-electrolytes: - HOCH2CH3 (ethanol) - C12H22O12 (sucrose/table sugar)
match each type of radiation to the correct description
electromagnetic radiation- includes all the different types of light nuclear radiation- includes alpha ad beta particles as well as gamma radiation
A(n) ____ force of attraction is an attraction that occurs between molecules
intermolecular
The O-H bond ____ than C-S bond
is more polar
a(n) ____ cell converts light energy directly into electrical energy
photovoltaic (aka solar cell)
1 ppm
1 mg/L
Rank the following commodities according to the size of their water footprints, placing the commodity that has the smallest water footprint at the bottom of the list
1- 1 cotton tshirt 2- 1 chocolate bar 3- 1 glass of orange juice 4- 1 cup of tea
after 3 half-lives have passed, what % of the original radioactive isotope remains?
12.5
If a 5.00 minute shower needs 85.0 L water how much water would you save if you shortened your shower by 45.0 seconds?
12.7 L Step 1: L per min? 85.0 L/5.00 min = 17.0 L/min Step 2: L per second 17.0 L/1min x 1min/60 sec = 0.283 L/s Step 3: saved by shorten secs? 0.283 L/sec x 45 sec = 12.7 L
acetate
C2H3O2-
Which of the following options correctly describe the concentration terms ppm and ppb?
- 1 ppm is equivalent to 1 mg/L - 1 ppb is equivalent to 1 μg/1L
match percentages of Earth's water and fresh water with the appropriate water source
- 97% of earth's water: oceans - 3% of earth's water: fresh water - 68% of fresh water: glaciers, ice caps and snowfields - 30% of fresh water: aquifers - 1% of fresh water: atmosphere - 0.3% of fresh water: lakes, swamps, rivers
The isotope 39/20 Ca contains ___ protons and ___ neutrons in its nucleus
- C) 20;19 a) 20;39 b) 39;20 c) 20;19 d) 19;20
Which of the following ions are formed when CH3COOH (acetic acid) dissociates or ionizes in aqueous solution?
- CH3COO- - H3O+
Which of the following species play a role in maintaining the normal pH of seawater?
- HCO3- - CO2-/3 - H2CO3
Which of the following are strong bases?
- KOH - NaOH
Which of the following ions always form soluble ionic compounds?
- NH4+ - NO3- - Na+
Which of the following options correctly describe the pH scale?
- a solution with a pH of 3.0 is more acidic than a solution with a pH of 5.0 - the more acidic a solution is, the lower the pH
Identify every example of nuclear radiation
- beta particle - alpha particle
Which of the following statements describe the drawbacks of using chlorine-containing chemicals in the water treatment process?
- chlorine can react with organic matter to form trihalomethanes (THMs) - chlorine-containing chemicals can themselves be toxic - the taste and odor of residual chlorine is objectionable
Which of the following disadvantages are specifically associated with coal-based power plants but not nuclear power plants?
- generation of air pollutants - ash generation
Which of the following options correctly describe the factors that influence the ability of a nucleus to undergo fission?
- heavy nuclei may undergo nuclear fission if bombarded with high-energy neutrons - the number of protons and neutrons influence the ability of a nucleus to undergo fission - small nuclei are less likely to undergo fission
Which of the following options correctly describe the use of distillation as a desalination technique?
- it requires a lot of energy to desalinate water by distillation - MSF distillation technique is a modern technique used on a large scale - a new heating source used for distillation is solar power
Match each type of lake with the effect acidic precipitation will have on its pH
- lakes in limestone regions: resist decrease in pH when subjected to acidic precipitation - lakes in granite regions: show a decrease in pH due to acidic precipitation - excess acid is neutralized by: limestone - excess acid does not react with: granite
What waste is present in sewage that makes it more complicated to treat than contaminants found in water in the water treatment process?
- nitrate ions - organic compounds
Match each term with the appropriate definition
- osmosis: the passage of water through a semipermeable membrane from a solution that is LESS concentrated to a solution that is MORE concentrated - reverse osmosis: employing the use of pressure to force the movement of water through a semipermeable membrane from a solution that is MORE concentrated to one that is LESS concentrated
What are the consequences of a large amount of phosphates and nitrates in the water?
- oxygen depletion - dead fish - algal blooms
Match each pair of solutions to the correct description of their relative acidity
- pH of A= 3.0; pH of B= 4.0: A is 10 times more acidic than B - pH of A= 8.0; pH of B= 4.0: B is 10,000 times more acidic than A - pH of A= 6.0; pH of B= 8.0: A is 100 times more acidic than B - pH of A= 10.5; pH of B= 7.5: B is 1000 times more acidic than A
Match each pH range to the effect it has on organisms found in a lake
- pH= 6.5 or slightly higher: normal, healthy lake - pH below 6.0: many fish disappear - pH below 5.0: most aquatic life disappears - pH of 4.0 or lower: the lake is essentially dead
Which of the following options correctly describe aspects of the Fukushima-Daiichi nuclear disaster in Japan in 2011?
- radioactive materials were accidentally vented from the plant -reactor cooling systems failed - this disaster was precipitated by damage due to an earthquake and a tsunami
Solution A has a pH of 6.0, while solution B has a pH of 9.0. Which of the following options correctly describe these two solutions?
- the [H+] in solution A is 1000 times greater than the [H+] in solution B - solution A is more acidic than solution B
Which of the following options correctly describe the control rods in a nuclear reactor?
- the control rods are used to control the rate at which heat is generated - the control rods contain substances that absorb neutrons
Which of the following statements correctly explain why water is a polar molecule?
- water has polar bonds - water has bent geometry
What is the molarity of sodium chloride in a solution containing 0.50 mol of sodium chloride in 500 mL of water?
-- A) 1.0 M (remember that molarity is moles/L) A) 1.0 M B) 0.25 M C) 5.0 M D) 0.50 M
What percentage of water on earth is freshwater?
-- A) 3% A) 3% B) 30.1 % C) 0.3% D) 68.7%
How much acetic acid (CH3COOH) in grams, would be required to make 1 Liter of a 1.5 M acetic acid solution in water?
-- A) 90 A) 90 B) 30 C) 60 D) 45
Which of the following is not an advantage of locating wind turbines off-shore instead of on land?
-- A) Maintenance costs are lower off-shore A) Maintenance costs are lower off-shore B) Large numbers of people live near coastlines and could make use of the energy C) Land is scare, especially near coastlines D) The wind blows faster and more uniformly over water
To meet the electricity needs of the entire United States, a solar array the size of ________ would be required.
-- A) New Jersey A) New Jersey B) Texas C) Nevada D) New York City
Which is the best definition of specific heat?
-- A) The quantity of heat energy that must be absorbed to increase the temperature of one gram of a substance one degree Celsius A) The quantity of heat energy that must be absorbed to increase the temperature of one gram of a substance one degree Celsius B) The boiling point of a liquid substance in degrees Celsius C) The quantity of heat energy that must be absorbed to cause one gram of a liquid substance to boil D) The difference between the freezing point and the boiling point of a substance (remember that this relates mass, energy and temperature change)
Which form of water disinfection continues to provide antibacterial protection after the water leaves the purification plant?
-- A) chlorination A) chlorination B) UV radiation C) ozonation D) filtration
The bond between the two nitrogens in N2 gas is a(n)_________.
-- A) nonpolar covalent bond A) nonpolar covalent bond B) strong bond dipole C) polar covalent bond D) ionic bond
For a molecule to exhibit hydrogen bonding the H must be covalently bonded to a?
-- A,BC,) oxygen, nitrogen, fluorine (highly electronegative atom) A) oxygen B) nitrogen C) fluorine D) chlorine
If 1.8 × 1014 J is released in a nuclear reaction, how much matter was lost?
-- B) 2.0 × 10¯3 kg A) 6.0 × 105 kg B) 2.0 × 10¯3 kg (E = mc2 where c = 3.0 × 108 m/s) C) 7.2 × 102 kg D) 1.6 × 1031 kg
If you have 200.0 g of radioisotope with a half-life of 5 days, how much isotope would remain after 15 days?
-- B) 25.0 g A) 12.5 g B) 25.0 g (This is three half-lives.) C) 40.0 g D) 13.3 g
What is the atomic number of Pt-175 AFTER it undergoes alpha decay
-- B) 76 A) 173 B) 76 C) 74 D) 78
Complete the following statement while ignoring any thermodynamic considerations. A candle may be considered a more efficient producer of light than a flashlight because it
-- B) Converts chemical energy directly into light A) may be used in remote locations far from electrical networks or power lines B) Converts chemical energy directly into light C) Produced more heat than a flashlight D) Does not have a battery to recharge or replace
The hydronium ion concentration in a solution with pH 10 is ________ than the hydronium ion concentration in a solution with pH 13.
-- C) 1000 times greater A) 3 times greater B) 100 times less C) 1000 times less D) 1000 times greater
If the half-life of radon-222 is 3.82 days, then how much of a 10.0 gram sample of radon-222 would be left after 7.64 days
-- C) 2.50 g A) 10.0 g B) 1.0 g C) 2.50 g D) 5.0 g
When table sugar (sucrose, C12H22O11) dissolves in water, which type(s) of attraction between water and sugar molecules occur(s)? I. hydrogen bonding II. polar-polar interactions III. covalent bonding
-- C) I and II only A) II and III only B) I and III only C) I and II only D) I, II, and III (remember that covalent bonding means sharing electrons)
What atmospheric component is responsible for the natural acidity of rain?
-- C) carbon dioxide (this makes carbonic acid) A) nitrogen B) ozone C) carbon dioxide D) oxygen
Silicon doped with gallium would be an example of a(n) ___________.
-- C) p-type semiconductor A) doping B) n-type semiconductor C) p-type semiconductor D) p-n junction
Which shows the Lewis structure of water with the correct partial charges and nonbonding electrons?
-- C) δ+ H - δ- :O: - δ+ H δ+ on hydrogen atoms, δ- on oxygen with two lone pairs (Remember that the more electronegative element has the negative partial charge)
Which increases the efficiency of a photovoltaic or solar cell? I. Replacing crystalline silicon with its non-crystalline form II. Increasing the number of alternating p- and n-type layers of semiconductors III. Decreasing the thickness of each alternating p- and n-type layer of semiconductor
-- D) I, II, and III A) II and III only B) I and II only C) I and III only D) I, II, and III (There are many ways to increase efficiency, although they are not easy to accomplish in an industrial setting)
Predict the products of this reaction: KOH + HNO3 →
-- D) KNO3 + H2O A) KO4 + H2N B) KNO2 + H2O2 C) KH + HNO4 D) KNO3 + H2O (acid and base make a salt and water)
Which solution is acidic?
-- D) MOH¯ = 1.77 × 10^¯10 M A) MH+ = 1.27 × 10^¯9 M B) MOH¯ = 0.0065 M C) MH+ = 5.79 × 10^¯10 M D) MOH¯ = 1.77 × 10^¯10 M (if MOH- < 1 × 10^-7 this is acidic)
Which of the following molecules is polar?
-- D) NH3 A) CO2 B) SiF4 C) Br2 D) NH3 (ammonia contains relatively nonpolar bonds but is polar because it also contains a non-bonded electron pair)
Which type of renewable energy has most commonly been adapted for use on an individual home basis?
-- D) Photovoltaic A) Wind B) Biodiesel C) Hydroelectric D) Photovoltaic
match number of half-lives that have passes with the percentage of the original sample remaining
1 half life- 50% 2 half lives- 25% 3 half lives- 12.5% 4 half lives- 3.13%
1 ppb
1 μg/L
Correctly order the steps showing the effect of decreased ocean pH on marine organisms such as coral. Start with the first step at the top of the list
1- CO2 (aq) + H2O (l) → H2CO3 (aq) 2- H2CO3 (aq) → H+ (aq) + HCO3- (aq) 3- H+ (aq) + CO2-/3 (aq) → HCO3- (aq) 4- CaCO3 (s) → Ca^2+ (aq) + CO2-/3 (aq)
place the steps that show how CO2 produces an aqueous solution in water in the correct order
1- CO2 (g) → (h2o at top of arrow) CO2 (aq) 2- CO2 (aq) + H2O (l) → H2CO3 (aq) 3- H2CO3 (aq) → H+ (aq) + HCO3- (aq)
Rank the following solutions in order of increasing acidity, starting with the least acidic solution at the top
1- [OH-]= 1x10^2 2- [H+]= 1x10^-8 3- [H+]= 1x10^-6 4- [OH-]= 1x10^-12
Arrange the phases of water form the least dense to the most dense, starting with the least dense at the top
1- gaseous 2- solid 3- liquid
place the steps involved in producing electricity from nuclear power in correct order, starting with the first step at the top
1- heat is generated by nuclear reactions in a reactor vessel 2- heat is transferred to the primary coolant 3- the primary coolant transfers heat to a steam generator 4- a steam turbine transfers energy to an electrical generator
Rank the following solutions in order of increasing acidity based on their pH values, starting with the least acidic solution at the top of the list
1- household ammonia with PH of 11.5 2- seawater with pH of 8.2 3- rainwater with pH of 5.3 4- tomato juice with pH of 4.1
Place the following common substances in order of decreasing pH (increasing acidity), starting with the least acidic substance at the top of the list
1- oven cleaner 2- blood 3- pure water 4- milk 5- coca cola
For an aqueous solution with a H+ concentration of 1.0 x 10^-3 M, calculate the concentration of OH-. Answer in scientific notation
1.0 x 10^-11
Silicon is used for solar panels is found to be 99.9999% pure. What is the concentration of impurities in ppb?
1000 ppb percent concentration: 100% -99.9999%= 1x10^-4 convert to ppb: 1x10^-4% x (1x10^7 ppb/%)= 1000 ppb
A solution with a pH of 3.0 is ____ times ____ acidic than a solution with a pH of 4.0
10; more
If you want to prepare .50 liters of a 0.25 M solution of NaNO3, how many grams of the salt should you weigh out?
11 g Step 1: How many moles present in solution? 0.25 mol/1L x .50L = 0.13 mol NaNO3 Step 2: Molar mass? 85 g/mol Step 3: How many grams of salt needed? 0.13 mol x 85g/1 mol = 11 g
What is the molarity of a solution that contains 5.0 ppm of tin?
4.2 x 10^-5 M
The symbol 244/94 Pu represents the isotope of plutonium. Match each part of the symbol with its correct meaning
94 represents the: atomic number 244 represents the: mass number There are 94: protons in the nucleus There are 244: protons + neutrons in the nucleus
Match each process or reagent in the treatment of water with the appropriate letter on the illustration
A- flocculating agents B- flocculator C- charcoal and sand filter D- chlorination E- fluoridation
match each type of radioactive emission to the correct description
Alpha particle- positively charged, consists of 2 protons and 2 neutrons Beta particle- high-speed electron emitted from the nucleus Gamma ray- high-energy photon, with no charge or mass
Some gases are soluble enough in water to dissolve to produce an acidic solution, although in some cases only slightly so. Which gas can dissolve in water to produce H2CO3 (aq)?
CO2 H2O + ? = H2CO3
carbonate
CO2-/3
Using the patterns evident in a table of electronegativity values, predict whether K or Ca has the higher electronegativity
Ca
Which of the following is the correct condensed molecular formula for water?
H2O
A chemical equation can be written to show the release of one hydrogen ion from H3PO4. Give the chemical formula for the anion (negatively charged ion) that is produced
H2PO-/4 (one H+ is lost so subtract one H and make it negative)
Which of the following balanced equations correctly represents the dissociation of K2SO4 in water?
K2SO4 (s) → 2K+ (aq) + SO2-/4 (aq) (K2SO4 consists of K+ ions and SO2-/4 ions, which dissociate from each other in aqueous solution. Each unit of K2SO4 forms two K+ ions and one SO2-/4 ions)
Although it is nor usually used, Einstein's equation, E=mc^2 applies to chemical reactions as well as nuclear reactions. A combustion reaction released 65 kJ when one gram of a reactant was burned. How much of this mass was lost in the process? 1 joule= 1 kilogram-meter^2/second^2
Mass loss is 7.2 x 10^-10 g step 1: in order to have joules (J) as the unit of energy (E) the mass (m) must be in kilograms. In addition you need to conversion factor that 1 joule= 1 kilogram-meter^2/seconds^2 step 2: 65 kJ x 10^3 J/1 kJ x 1 /1 J x 10^3 g/1 kg x (1 s/ 3.00x10^8 m)^2 = mass, g
ammonium
NH4+
Which of the following gases produce acidic solutions in water?
NO2, SO2, CO2
nitrate
NO3-
match each bond with the appropriate difference in electronegativity
O-H: 1.4 F-H: 1.9 S-Cl: 0.5 Si-F: 2.2
hydroxide
OH-
Which of the following gives the best explanation for why oil and water do not mix?
Oil does not mix with water because oil is nonpolar and water is polar
Phosphate
PO3-/4
particles involved in nuclear reactions
Protons: 1/1 p Alpha particle (helium atom): 4/2 He or a Beta particle (electron): 0/-1 B Gamma radiation (a high-energy photon): 0/0 y Positron particle (same mass as electron but carries positive charge): 0/1 B
As [H+] in solution increases, the pH of the solution ____
decreases
the process of intentionally adding small amounts of other element to pure silicon is called ____
doping
a weak acid is also a weak ___
electrolyte
The ability of a covalently bonded atom to attract the shared electrons is called ____
electronegativity
____ is used for medical imagine, especially for diagnosing ____ problems. ____ has half life of 5717 years. It is incorporated into ____ and is useful for determining their age. ____ is a product in the radioactive decay series of uranium. It is a ___ which accumulates in ____, affecting the air quality in our homes. ___ has a very long half life of 4.5 billion years, so it is good for determining the age of ____ ____ closely resembles calcium and will be incorporated into the ____ when people who are exposed to it
iodine-131; thyroid carbon-14; living things radon-222; gas; basements uranium-238; rocks strontium-90; bones
Acids are covalently bonded substances that nonetheless produce ____ when dissolved in water. The attraction between the polar acid molecule and polar H2O molecules cause the acid to ____ or break down to form ions
ions; dissociate
what is the specific danger associated with the radioactive isotope iodine-131?
it causes thyroid cancer
Why is NH3 able to act as a weak base?
it reacts with H2O to release small amounts of OH- ions
Photovoltaic cells (PVs) convert ____ energy into electrical energy PVs are made from ____. Two different types are ____ n-type semiconductors ____ and p-type semiconductors ____. ____ such as gallium or ____ are added to allows electrons to flow through the silicon semiconductor. when a ___ with enough energy hits the PV, an "extra" electron is "knocked" from one layer into a ___ in the other. The movement of ____ is an electrical current.
light; electrical semiconductors; layered; have extra electrons; need more electrons dopants; arsenic photon; "hole"; electrons
ppb
mass (g) of solute/ 1x10^9 g solution
Unit of concentration mole/liters of solution
molarity
Molarity
moles of solute (mol)/liters of solution (L)
the symbol ⇌ used in an equation indicates that a particular reaction ___
occurs in both the forward and reverse directions at the same time
the primary and secondary coolants in a nuclear power plant have very different but equally vital roles. Label each coolant with its characteristics
primary coolant: -heated directly by energy given off by nuclear fuel - aqueous boric acid absorbs radiation - links the nuclear reactor to the rest of the power plant - will contain radioactive material secondary coolant: - creates steam to turn a turbine and generate electricity -fluid is cooled by a condenser and recycled - does not contact the reactor
a critical mass is
the amount of fissionable fuel required to sustain a chain reaction
solvent
the majority component of the solution
Which of the following substances is most frequently used as the secondary coolant in a nuclear power plant?
water
Potable water
water that is safe to drink and cook with
An ionic compound will produce an aqueous solution when the attraction between the ____ molecules and the ions is greater than the attraction between the ____ themselves. Ion size and charge can also play a role in the solubility of ionic compounds.
water; ions
An acid such as H2CO3, which dissociates to only a small extent in water, is called a(n) ____ acid
weak
Match each letter in the following nuclear equation with the correct value or symbol in each case. 235/92 U + 1/0 n -> x/38 A + 140/y B + 2 1/0 n
x: 94 (235 + 1= x + 140 + 2; x=94) y: 54 (90 +0=38 +y +0; y=54) A: Sr (the atomic number 38 identifies with element A as Sr) B: Xe (once you have calculated y to be 54, this atomic number identifies element B as Xe)