# Posts by Cheri

Total # Posts: 159

ICP
What is the value of work done on an object when a 10-newton force moves it 30 meters and the angle between the force and the displacement is 25°?

math
if a movie theater holds 1200 and 2/3 of its seat how many tickets does sell

english
What is the exposition in the book Poseidon's arrow?

math
A college student wishes to compare tuition fee increases during the period 1999 to 2009 to the general increase in the cost of living. Tuition increased from \$350 per course in the 1999/2000 academic year to \$495 per course in the 2009/10 academic year. The CPI rose from 92.9...

comp/155
I am having problems writing a essay and not really sure how to start.

ap chemistry
Rank the compounds CH3OH CH3CH2OH CH3CH2CH2OH in terms of increasing evaporation rate. 1. CH3CH2CH2OH < CH3OH < CH3CH2OH 2. CH3OH < CH3CH2CH2OH < CH3CH2OH 3. CH3OH < CH3CH2OH < CH3CH2CH2OH 4. CH3CH2OH < CH3CH2CH2OH < CH3OH 5. CH3CH2CH2OH < CH3CH2OH &...

ap chemistry
What amount of energy is required to com- pletely ionize 26.9 grams of carbon atoms in the gas phase (C(g)) if the ionization energy of C(g) is 1086 kJ/mole? Answer in units of J

ap chemistry
Benzene is a hydrocarbon that is commonly used as a commercial solvent. However, it is carcinogenic; i.e., accumulations in the body can cause cancer. What is the vapor pressure of benzene at 29C? The normal boiling point of benzene is 80.0C and its molar heat of ...

ap chemistry
Use the Clausius-Clapeyron equation to cal- culate the temperature at which pure water would boil at a pressure of 434 torr. The heat of vaporization of water is 41276 J/mol at 100C. Answer in units of C

ap chemistry
If 310mL of 2.2molar HCl solution is added to 135 mL of 3.6 molar Ba(OH)2 solution, what will be the molarity of BaCl2 in the resulting solution? Answer in units of M

ap chemistry
A 37 mL sample of a solution of sulfuric acid is neutralized by 42 mL of a 0.113 M sodium hydroxide solution. Calculate the molarity of the sulfuric acid solution. Answer in units of mol/L

ap chemistry
In neutralization reactions, acid + base ! salt + water HCl can be neutralized with NaOH. How many moles of NaOH will it take to neutralize 0.31 L of 0.7 M HCl? Answer in units of mol

ap chemistry
If 300 mL of 3.9 molar HCl solution is added to 200 mL of 2.2 molar NaOH solution, what will be the molarity of NaCl in the resulting solution? Answer in units of M

ap chemistry
A 0.456 gram sample of an unknown mono- protic acid (let’s call it HZ) was dissolved in some water (you pick the amount). Then the acidic solution was titrated to the equivalence point with 32.5 mL of 0.174 M KOH. What is the molecular weight of the unknown acid HZ? 1. ...

ap chemistry
i no the first one and last one are strong but i don't know about the others

ap chemistry
Which of I) HCl II) HF III) LiOH IV) HClO2 V) HNO3 are strong acids or strong bases in water?

ap chemistry
Acid rain has a pH value of 3.0, whereas normal rain has a pH value of 5.6. Calculate the ratio of the hydronium ion in acid rain to that in normal rain.

ap chemistry
1. HOI > HOBr > HOCl 2. HOCl > HOBr > HOI 3. HOBr > HOCl > HOI 4. None of these 5. HOI > HOCl > HOBr

ap chemistry
Given the following information, which of the following shows the acids in order from strongest to weakest? The order of atomic radii is I > Br > Cl, the order of bond strengths is HOI > HOBr > HOCl, and the order of electronegativities is Cl > Br > I.

ap chemistry
Arrange the bases I) deuterated ammonia (ND3) Kb = 1.1 × 10−5; II) hydrazine (NH2NH2) Kb = 1.7 × 10−6; III) hydroxylamine (NH2OH) Kb = 1.1 × 10−8; IV) ammonia (NH3) Kb = 1.8 × 10−5; in decreasing order of strengths.

ap chemistry
Iron pyrite (FeS2) is the form in whichmuch of the sulfur exists in coal. In the combustion of coal, oxygen reacts with iron pyrite to produce iron(III) oxide and sulfur dioxide, which is a major source of air pollution and a substantial contributor to acid rain. What mass of ...

ap chemistry
We drop 37.4 grams of magnesium into 461 mL of a 3 M HCl solution. What is the maximum volume of dry hydrogen that could be produced by this reaction at STP? Mg(s) + 2HCl(aq) ! MgCl2(aq) + H2(g) Answer in units of liters

ap chemistry
We observe that 5 grams of a gaseous com- pound occupies 1526 mL at 49C and 672 torr. What is the molecular weight of the com- pound? Answer in units of g/mo

ap chemistry
for the first one i did 2 divided by 14 times 819 and got 116.99 but i don't know how to do the other two problems

ap chemistry
An apparatus consists of a 2 L flask containing nitrogen gas at 25C and 819 kPa, joined by a valve to a 12 L flask containing argon gas at 25C and 51 kPa. The valve is opened and the gases mix. What is the partial pressure of nitrogen after mixing? Answer in units of...

ap chemistry
We observe that 5 grams of a gaseous com- pound occupies 1526 mL at 49C and 672 torr. What is the molecular weight of the com- pound? Answer in units of g/mol

ap chemistry
A 6.9 gram sample of a gaseous substance occupies 10 L at 63C and 537 torr. What is the density of the gas under these conditions? Answer in units of g/L

ap chemistry
We mix 146 grams of oxygen gas with 117 grams of argon gas in a volume of 436 mL at 58C. What will be the final pressure of the gas mixture? Answer in units of atm

ap chemistry
Jeff and Jill go canoeing. While reaching to feed a duck, the boat flips. Jeff and Jill blow up their inflatable life preservers and then put them on. As they wait for the rescue squad, they calculate how much nitrogen is in each life preserver. They estimate that the volume ...

ap chemistry
What pressure would a mixture of 3.2 grams of O2, 6.4 grams CH4, and 6.4 grams of SO2 exert if the gases were placed in a 5.1 liter container at 127C? Answer in units of atm

ap chemistry
An oxygen sample has a volume of 5 L at 27C and 800 torr. How many oxygen molecules does it contain?

ap chemistry
Nitroglycerin is a shock-sensitive liquid that detonates by the reaction 4C3H5(NO3)3(`) −! 6N2(g) + 10H2O(g) + 12CO2(g) + O2(g) Calculate the total volume of product gases at 210 kPa and 296C from the detonation of 2.7 lb (1224.7 g) of nitroglycerin. Answer in units...

ap chemistry
A 115 mg sample of eugenol, the compound responsible for the odor of cloves, was placed in an evacuated flask with a volume of 500 mL at 280C. After the eugenol completely evap- orated, the pressure that it exerted in the flask under those conditions was found to be 48.3 ...

ap chemistry
What is the density of hydrogen sulfide (H2S) at 0.9 atm and 295 K? Answer in units of g/L

ap chemistry
A sample of gas occupies 4 mL at STP. At what pressure would this sample occupy 500 mL if the temperature is changed to 525C? Answer in units of torr

ap chemistry
To what temperature must a sample of helium gas be cooled from 123C to reduce its volume from 3.7 L to 0.27 L at constant pressure? Answer in units of K

ap chemistry
A 1.50 liter tank filled with helium at 125 atm is used to fill balloons. The pressure in each balloon is 950 torr and the volume of each balloon is 1.20 liters. How many balloons can be filled? Answer in units of balloons

ap chemistry
Suppose that a sample of gas occupies 117 mL of volume at 25C and a pressure of 289 torr. What would be the volume if the pressure were changed to 490 torr at 25C? Answer in units of mL

ap chemistry
On a hot sunny day in August, the weather- man reports that the barometric pressure is 49 atm atmospheres. How many Pascals is this? Answer in units of Pascals

ap chemistry
The system CO2(g) + H2(g) *) H2O(g) + CO(g) is at equilibrium at some temperature. At equilibrium a 4.00 L vessel contains 1.00 mole CO2, 1.00 mole H2, 2.40 moles H2O, and 2.40 moles CO. How many moles of CO2 must be added to the system to bring the equilibrium CO ...

apchemistry
The numerical value of the concentration equilibrium constant for the gaseous reaction 2 SO2 + O2 *) 2 SO3 is 0.5 at temperature T. When a reactionmix- ture is brought to equilibrium, [O2] is found to be 2.0 M and [SO3] is found to be 10 M. What is the equilibrium ...

ap chemistry
At 350 K, Kc = 0.142 for the reaction 2BrCl(g) *) Br2(g) + Cl2(g) An equilibrium mixture at this temperature contains equal concentrations of bromine and chlorine, 0.069 mol/L. What is the equilib- rium concentration of BrCl? Answer in units of M

ap chemistry
At a certain temperature, the equilibrium constant Kc is 0.154 for the reaction 2 SO2(g) + O2(g) *) 2 SO3(g) What concentration of SO3 would be in equilibrium with 0.250moles of SO2 and 0.853 moles of O2 in a 1.00 liter container at this temperature? Note: These latter moles ...

ap chemistry
Consider the reaction Ni(s) + 4CO(g) ! Ni(CO)4(g) Assuming the gases are ideal, calculate the work done on the system at a constant pres- sure of 1 atm at 75C for the conversion of 1.00 mole of Ni to Ni(CO)4.

ap chemistry
How much work is done by the system when 2.00 moles of O2 expand from a volume of 3.00 liters to a volume of 8.1 liters against a constant external pressure of 0.0100 atm? Answer in units of J

ap chemistry
What is the value of w (work) when 1.3 moles of H2 expands from 25 liters to 50 liters against a constant external pressure of 1 atm, then expands further from 50 to 100 liters against a constant external pressure of 0.1 atm? Answer in calories. Answer in units of cal

ap chemistry
1.95 mol of an ideal gas at 300 K and 3.00 atm expands from 16 L to 28 L and a final pressure of 1.20 atm in two steps: (1) the gas is cooled at constant volume until its pressure has fallen to 1.20 atm, and (2) it is heated and allowed to expand against a constant pressure of...

ap chemistry
A sample of gas in a cylinder of volume 4.09 L at 289 K and 3.43 atm expands to 7.73 L by two different pathways. Path A is an isothermal, reversible expansion. Calculate the work

ap chemistry
How much heat is released if 2.00 moles CF2Cl2 reacts with 70.0 g F2 with a 75.0 percent yield? CF2Cl2 + F2 ! CF4 + Cl2 H for this reaction is -401 kJ/mol rxn. 1. 553 kJ 2. 739 kJ 3. 985 kJ 4. 601 kJ 5. 1069 kJ 6. 802 kJ

ap chemistry
Propane (C3H8) is burned in oxygen to pro- duce carbon dioxide and water. The heat of combustion of propane is -2012 kJ/mole. How much heat is given off when 3.0 mol C3H8 are reacted with 10.0 mol O2? 1. 4024 kJ 2. 2012 kJ 3. 916 kJ 4. 1555 kJ 5. 5122 kJ 6. 672 kJ 7. 6036 kJ 8...

ap chemistry
The energy change H associated with the reaction NBr3(g) + 3H2O(g) ! 3HOBr(g) + NH3(g)is +81 kJ/mol rxn. These bond energy values might be useful:O-H 459 kJ/mol; N-H 386 kJ/mol;O-Br 201kJ/mol. The strength of the N Br bond is

ap chemistry
1. 2H(g)+O2(g)->H2O2 2. Na(s)+1/2Cl2->NaCl(s) 3. Co2(s)->Co2(g) 4. So2(g)+1/2O2->So3(g) 5. 2H2(g)+O2(g)->2H2O

ap chemistry
Which of the following reactions as written corresponds to a standard formation reaction? 1. 2H (g) + O2(g) ! H2O2 (`) 2. Na(s) + 1 2 Cl2(g) ! NaCl(s) 3. CO2(s) ! CO2(g) 4. SO2(g) + 1 2 O2(g) ! SO3(g) 5. 2 H2(g) + O2(g) ! 2 H2O(`)

ap chemistry
Carbon monoxide reacts with oxygen to form carbon dioxide by the following reaction: 2CO(g) + O2(g) ! 2CO2(g) H for this reaction is −135.28 kcal. If 811.7 kcal is released, how many moles of CO must have reacted?

ap chemistry
What types of intermolecular interactions does chloroform (CH3Cl) exhibit? I) London dispersion II) dipole-dipole III) hydrogen bonding IV) covalent bonding Recall that chloroform is tetrahedral elctronic geometry with C as the central atom.

ap chemistry
Calculate the standard reaction enthalpy for the reaction NO2(g) ! NO(g) + O(g) Given: O2(g) ! 2O(g) H = +498.4 kJ/mol NO(g) + O3(g) ! NO2(g) + O2(g) H = −200 kJ/mol 3O2(g) ! 2O3(g) H = +285.4 kJ/mol

ap chemistry
Consider the reaction 2 Al2O3(s) -> 4 Al(s) + 3 O2(g) . H = +3339.6 kJ/mol How much heat is generated when 0.455 L of a 3.60 M Al solution reacts with 1.05 mole O2 ?

ap chemistry
3.5 g of a hydrocarbon fuel is burned in a ves- sel that contains 250. grams of water initially at 25.00 C. After the combustion, the temper- ature of the water is 26.55 C. How much heat is evolved per gram of fuel burned?

ap chemistry
Consider the reaction 2 Al2O3(s) ! 4 Al(s) + 3 O2(g) . H = +3339.6 kJ/mol What is the change in heat when 0.455 L of a 3.60 M Al solution reacts with excess O2 ?

ap
The reaction 2Na+ + 2Cl− ! 2Na + Cl2 is indicative of ? cell; the sign of the anode is ? ; and ? forms at the cathode. 1. an electrolytic; negative; Na+ 2. a voltaic; positive; Na 3. an electrolytic; positive; Na 4. an electrolytic; positive; Cl2 5. a voltaic; negative; Cl2

ap
Sodium, potassium, and rubidium are good 1. oxidizing agents. 2. reducing agents. 3. bases.

ap
A saturated solution of which of the follow- ing substances in water would be the best conductor of electricity? 1. CH4 2. Hg2Cl2 3. HCl 4. NH3 5. CH3COOH

ap
What is a poor conductor of electricity? 1. mercury 2. molten NaCl 3. copper 4. potassium 5. sulfur

ap
For an electrochemical reduction process, electrons are 1. taken from solution species at the surface of the cathode. 2. added to solution species at the surface of the anode. 3. added to solution species at the surface of the cathode.

ap
Chlorine, bromine, and iodine are good 1. oxidizing agents. 2. reducing agents. 3. bases.

ap
In a voltaic cell, electrons flow from the ? to the ? in the external circuit. 1. cathode; anode 2. products; reactants 3. anode; cathode 4. reactants; products

ap
A battery has two electrodes labeled anode and cathode. Electrons flow from the (anode, cathode) to the (anode, cathode) through the external circuit and (an oxidation, a reduc- tion) reaction occurs at the cathode. 1. anode; cathode; reduction 2. cathode; anode; oxidation 3. ...

ap
Very small mercury batteries have been made and used in a multitude of applications. Why have they been replaced by other kinds of batteries for most applications? 1. These batteries cannot generate enough current for any modern devices. 2. Mercury is poisonous and difficult ...

ap
A ruptured tank in Anywhere, USA, spilled hydrochloric acid. Officials were reported to be concerned that the acid might mix with sodium hydroxide (caustic soda) in a neigh- boring tank and form a toxic gas. What toxic gas would be formed by mixing hydrochloric acid with ...

ap
Which of the following metals or nonmetals are expected to displace Mn or Cl (respec- tively) from MnCl2? 1. Cu should displace Mn. 2. I should displace Cl. 3. Ca should displace Mn. 4. Br should displace Cl.

ap
Classify the reaction (NH4)2Cr2O7 ! N2 + 4 H2O + Cr2O3 as one or more of the following: Z1) combination Z4) metathesis Z2) decomposition Z5) displacement Z3) redox 1. Z2 only 2. Z2 and Z5 only 3. Z2 and Z3 only 4. Z3 and Z5 only 5. Z1 and Z3 only

ap
Identify the type of reaction C4H10(g) + O2(g) ! CO2(g) + H2O(g) 1. hydrocarbon synthesis 2. single displacement 3. incomplete combustion 4. complete combustion

ap
The net ionic equation for ALL aqueous reac-tion of strong acids and strong soluble bases that form soluble salts is 1. the formation of H2O from H+ and OH−. 2. the formation of water and the corresponding salt. 3. the formation of water from the elements. 4. the ...

ap
Which of the following is best described as an acid-base reaction? 1. NaCl + AgNO3 !NaNO3 + AgCl 2. NH3 + H2O ! NH+ 4 + OH− 3. 2HgO ! 2 Hg + O2 4. Ca + 2H2O ! Ca(OH)2 + H2 5. KCl + NH4NO3 ! KNO3 + NH4Cl

ap
If aqueous hydrofluoric acid is reacted with sodium hydroxide, which of the following sub- stances are in the net ionic equation? 1. fluoride ion, hydronium ion, and water 2. hydrofluoric acid, sodium ion, hydroxide ion, and fluoride ion 3. hydrofluoric acid, hydroxide ion, ...

ap
A volume of equimolar strong acid like HCl is mixed with an equal volume of equimolar strong base like NaOH in a beaker of water. What exists after the reaction? 1. mostly water molecules and HCl, NaOH, and NaCl molecules 2. mostly water molecules and Na+ and Cl− ions 3...

ap
An excess of aqueous AgNO3 reacts with 44.5 mL of 5 M K2CrO4(aq) to form a precip- itate. What is the precipitate? 1. K2CrO4 2. KNO3 3. Ag2CrO4 4. AgNO3 What mass of precipitate is formed? Answer in units of g

ap
An excess of aqueous AgNO3 reacts with 44.5 mL of 5 M K2CrO4(aq) to form a precip- itate. What is the precipitate? 1. K2CrO4 2. KNO3 3. Ag2CrO4 4. AgNO3

chemistry
Which compound on the left, when dissolved in water, does not produce the corresponding compound(s) on the right? 1. CaO ! Ca(OH)2 2. SO2 ! H2SO4 3. NaH ! NaOH + H2 4. N2O5 ! HNO3 5. Cl2O7 ! HClO4

chemistry
HCN is mixed with water. Which is the best description of what you would expect to find in the solution? 1. CN+, OH−, and water molecules 2. HCN molecules and water molecules 3. H2CN+, OH−, and water molecules 4. HCN molecules, H3O+, CN1−, and water molecules...

chemistry
HBr is mixed with water. Which is the best description of what you would expect to find in the solution? 1. Br1−, OH1−, and water molecules 2. HBr molecules and water molecules 3. H2Br+, OH1−, and water molecules 4. H3O+, Br1−, and water molecules 5. Br...

chemistry
An ion can be removed from an aqueous solu- tion by 1. the formation of a gas that escapes. 2. formation of a precipitate. 3. the formation of what is essentially a nonelectrolyte. 4. All of these

chemistry
Suppose that you wanted to be sure that a metal ion, any metal ion, would dissolve in water. What salt of the metal ion compound would you choose? 1. the hydroxide (OH−) salt of the metal ion 2. the carbonate (CO2− 3 ) salt of the metal ion 3. the nitrate (NO−...

chemistry
Which of the species KClO2, NH4Br, HNO2, PbS is/are insoluble in water? 1. NH4Br and NH3 2. KClO3 3. PbS 4. HNO2 5. All of these

chemistry
Which response includes all of the following LiOH, KOH, Ni(OH)2, Mg(OH)2, Ca(OH)2 that are insoluble bases, and no others? 1. Mg(OH)2 2. LiOH, Mg(OH)2, Ca(OH)2 3. Mg(OH)2, Ca(OH)2 4. Ni(OH)2, Mg(OH)2 5. LiOH, Ni(OH)2

chemistry
Which one of the following substances is LEAST soluble in water? 1. BaCO3 2. KSCN 3. Na3PO4 4. RbOH 5. LiBr

chemistry
Although soluble barium compounds are toxic, suspensions of insoluble barium sul- fate are routinely swallowed for upper gas- trointestinal X-ray studies. Why is barium carbonate not used? 1. Stomachs contain HCl and all carbonates dissolve in acid.2. Barium carbonate is too ...

chemistry
Which of the following aqueous solutions should NOT form a precipitate with aque- ous Ba(NO3)2? 1. K3PO4 2. K2SO4 3. K2CO3 4. KOH

chemistry
Which of the following aqueous solutions should form a precipitate with aqueous Fe(NO3)3? 1. KNO3 2. KCl 3. K2SO4 4. KOH

chemistry
Consider the following reaction CaCl2(aq) + 2Ag2SO4(aq) ! CaSO4(?) + 2AgCl(?) .Which of the following statements is true? 1. Both CaSO4 and AgCl will precipitate from solution. 2. Neither CaSO4 nor AgCl will precipitate from solution. 3. CaSO4 will precipitate from solution, ...

chemistry
A variety of ions including Na+, K+, NH4 +, Pb2+, Fe2+, NO3 −, Cl−, Br−, S2−, and CO3 2− are mixed in a beaker of water. If you analyzed the precipitates, which substances would you expect to find? 1. PbS and FeCO3 2. FeCl2 and KCl 3. NaBr and Pb(...

chemistry
If you analyzed each of the substances NaBr, KOH, CrPO4, Pb(OH)2, RbCl, LiNO3 by mixing them with water in a beaker, which substances would be most likely to fall to the bottom of the beaker? 1. KOH and Pb(OH)2 2. CrPO4 and LiNO3 3. NaBr 4. RbCl and LiNO3 5. CrPO4 and Pb(OH)2 ...

chemistry
yes its suppose to go on the previous problem

chemistry
What volume of water was added to the 350 mL of NaOH solution? Assume volumes are additive. Answer in units of mL

chemisry
An unknown amount of water is mixed with 350 mL of a 6 M solution of NaOH solution. A 75 mL sample of the resulting solution is titrated to neutrality with 52.5 mL of 6 M HCl. Calculate the concentration of the di- luted NaOH solution. Answer in units of M

chemistry
In choosing a primary standard we generally choose something that 1. All of these are properties we want in a primary standard. 2. has a low percent purity. 3. None of these are properties we want in a primary standard. 4. has several different possible reaction pathways. 5. ...

chemistry
What mass of silver nitrate (AgNO3) is re- quired to prepare 400 g of a 3.50% solution of AgNO3? 1. 14 g 2. 0.00875 g 3. 114.28 g 4. 1400 g

chemistry
Listerine mouthwash is 21.6%ethyl alcohol by volume. What mass of ethanol is contained in 20.0 mL of mouthwash? (The density of ethanol is 0.789 g/mL.) Answer in units of grams

chemistry
A solution of sodium hydroxide is standard- ized against potassium hydrogen phthalate (KHP, formula weight 204.2 g/mol). From the following data, calculate the molarity of the NaOH solution: mass of KHP 1.744 g; buret reading before titration 0.13 mL; buret reading after ...

chemistry
We add excess Na2CrO4 solution to 27.0 mL of a solution of silver nitrate (AgNO3) to form insoluble solid Ag2CrO4. When it has been dried and weighed, the mass of Ag2CrO4 is found to be 0.420 grams. What is the molarity of the AgNO3 solution? Answer in units of M

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