Friday
August 26, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
To charge a lead storage battery you must apply a direct current to it. hold a magnet close to it.*** force alternating current through it. increase the pressure on it.
Thursday, May 26, 2016 by Katie

General Chemistry
A 1/5 mmol (yes, millimol... no, it isn't a typo_ sample of XeFn h as a mass of 0.311 g. What is the value of n? The answer is 4, but why?
Thursday, May 26, 2016 by Kayla

chemistry
How to calculate number of electrones in 18 ml of water givan that density of water is 1g/cc
Thursday, May 26, 2016 by anu mol

chemistry
How many grams of CO2 are evolved on heating 200 g of CaCO3.
Thursday, May 26, 2016 by anu mol

Chemistry
Why must not the condensed water drip into the flask?
Wednesday, May 25, 2016 by Vaisamoa Tokauea

Chemistry
When it comes to something being spontaneous, what does it mean? I know its something that goes out without no outside force or something like that but what are example of something that is spontaneous ?
Wednesday, May 25, 2016 by Kat

Chemistry
What is the change in enthalpy of the following reaction? 2NaBr(aq) + PbCl2(aq) 2NaCl(aq) + PbBr2(aq) Given: NaCl: ∆H = -411 kJ NaBr: ∆H = -360 kJ PbCl2: ∆H = -359 kJ PbBr2: ∆H = -277 kJ Im lost with this. Everytime I try to do it, it doesn't come ...
Wednesday, May 25, 2016 by Kat

Chemistry
Balance the following redox equation using the oxidation number change method. Describe each step that is involved: Al(s) + PbSO4 - - > Al2(SO4)3 + Pb(s)
Wednesday, May 25, 2016 by Genna

Chemistry
In the most common dry cell what material is the electrode that is the center rod made of? copper graphite iron*** zinc
Wednesday, May 25, 2016 by Genna

Chemistry
What assures that there is no charge build up in a voltaic cell as oxidation and reduction occur? one of the half cells the electrolyte solutions*** the moving electrons the salt bridge
Wednesday, May 25, 2016 by Genna

Chemistry
aluminum hydroxide is decomposed to form aluminum oxide and water. if 2.23 moles of water are formed then how many of aluminum oxide are formed. how many grams of aluminum hydroxide must have been.decomposed?
Wednesday, May 25, 2016 by Alisha

Chemistry
The bond angle of water is decreased from 109Degree 28' to 104Degree 24',why?
Wednesday, May 25, 2016 by Pappu kumar sah

Chemistry
In the zinc-copper cell, Zn(s) | Zn^+2(1M) || Cu^+2(1M) | Cu(s), which electrode is negative Cu^+2 Cu(s) Zn(s) Zn^+2***
Wednesday, May 25, 2016 by Lara

Chemistry
Of the following metals, which ions are most easily reduced? aluminum*** iron mercury potassium
Wednesday, May 25, 2016 by Lara

Chemistry
Which atom has a change in oxidation number of –3 in the following redox reaction? K2Cr2O7 + H2O + S - - > KOH + Cr2O3 + SO2 Cr^+3 - - > Cr2O7^-2 Fe^+2 - - > Fe^+3 Fe^+3 - - > Fe^+2 Cr2O7^-2 - -> Cr^+3***
Wednesday, May 25, 2016 by Lara

Chemistry
what happens in a condensation reaction head-to-tail joining of monomers side-by-side joining of monomers cross-linking of monomers*** substitution of halogen
Wednesday, May 25, 2016 by Amy

chemistry
add any reducing agent to kmno4+k2cr2O7+k1 and reconcile the charges and equations
Wednesday, May 25, 2016 by omowhe

Chemistry
At 100 degrees C, pure H2O has a vapor pressure of 760 torr. An aqueous solution has a concentration of 1.90 M MgCl2. The van't Hoff factor is 2.45. The density of the solution is 1.09 g/mL. Calculate the vapor pressure of the solution.
Tuesday, May 24, 2016 by Ayaka

Chemistry
A 1.0L of an aqueous solution of ethylene glycol, HOCH2CH2OH, is 60% HOCH2CH2OH by mass and has a density of 1.15 g/mL. Calculate the morality of the solution.
Tuesday, May 24, 2016 by Ayaka

chemistry
A 2.00 L flask is filled with propane gas (C3H8)at 1.00 atm and -15.0 Degrees Celsius. What is the mass of the propane in the flask?
Tuesday, May 24, 2016 by Anna

CHEMISTRY
WHEN THE PH IS 0.4 WHAT IS THE COLOUR OF THE INDICATOR
Tuesday, May 24, 2016 by APY QUEEN

CHEMISTRY
USING EQUATION SHOW HOW AQUEOUS SOLUTION OF HYDROCHLORIC ACID CONTAINING HYDROXONIUM ION NEUTRALISED POTASSIUM HYDROXIDE
Tuesday, May 24, 2016 by APY QUEEN

CHEMISTRY
WHEN THE PH IS 4.0 WHAT IS THE COLOUR OF THE INDICATOR
Tuesday, May 24, 2016 by APY QUEEN

CHEMISTRY
THE BASICITY OF TETRAOXOSULPHATE6 ACID IS 2.EXPLAIN THE STATEMENT WITH EQU SHOWING REACTION BTW ACID&POTASRGUM HYDROXIDE
Tuesday, May 24, 2016 by APY QUEEN

Chemistry
A saturated solution of lead ii trioxonitrte v was prepared at 22degree Celsius at 27cm3 of this solution required 46cm3 of NaCl solution containing 96gdm3 for complete precipitation. Find the solubility of the lead in trioxonitrte v at 22degree Celsius in (a) mol/dm3 (b) g/dm3.
Tuesday, May 24, 2016 by Mohammed

chemistry
What is the specific heat capacity of a metal if it requires 175.0 J to change the temperature of 15.0 g of the metal from 25.00°C to 35.00°C? 1.17 J/g°C 11.7 J/g°C .875 J/g°C 325 J/g°C 17.5 J/g°C
Tuesday, May 24, 2016 by Ha

chemistry
A is a solution of trioxonitrate(v) acid, HNO3, of unknown concentration. B is standard solution of sodium hydroxide containing 4.00g per dm3 of solution. 25cm3 portions solution B required an average of 24.00cm3 of solution A for neutralization, using 2drops of methyl orange...
Tuesday, May 24, 2016 by oward

chemistry
How much mole of dry hydrogen at NTP is liberated on heating 0.1 mole of Mg with excess of dilute HCl? Actually what is NTP? I know the balaned equation and 1mole Mg forms 1 mole H2 , then 0.1 mole forms 1/0.1 moles of H2? Plz help
Monday, May 23, 2016 by anu mol

Chemistry
Complete the following equations: 1. Benzene + hydrogen fluoride ----> 2. Propanoic acid + ethanol ----> 3. 3-pentanol --->(oxidized)
Monday, May 23, 2016 by Rose

Chemistry
Complete the following equations. Include names of all reactants and products A) CH3CH2CHCH - CH2+H2O --> | CH3 B) CH3CHC=CCH3 + H2 ---> | CH3
Monday, May 23, 2016 by Rose

Chemistry help asap
what two ingredients are used to prepare basic buffer solution??
Monday, May 23, 2016 by Naz

Chemistry
50 L of your 0.05M sodium. chloride solution, what volume of 1.25M solution would be necessary?
Monday, May 23, 2016 by Blake

Chemistry
Put the following in order, from the one with the greatest impact on reaction rate to the one with the least impact on reaction rate: temperature, amounts of reactant, and presence of catalyst.
Sunday, May 22, 2016 by Anonymous

Chemistry
Given 100 mL of pure water at 40C, what volume of a solution of hydrochloric acid, with a density of 1.175 g/mL and containing 34.4% HCI by weight, could be prepared?
Sunday, May 22, 2016 by Sidney

Chemistry
Ammonia gas is passed into water, yielding a solution of density of 0.93 g/mL and containing 18.6% NH3 by weight. What is the mass of NH3 per mL of solution.
Sunday, May 22, 2016 by Kelly

Chemistry
I posted this before and I know now to use P1T2=P2T1 but I was wondering what I would plug in as pressure and temp? just an example of one would be so great. In each of the four problem in this section, all gases are measured at the same temperature and pressure. 1) (a) What ...
Sunday, May 22, 2016 by Eve

Chemistry
The air in a cylinder of a diesel engine occupies 1.00 L at 30 degrees celsius and 1.00 atm. What is the pressure in the cylinder when the air is compressed to 0.0714 L (14:1 compression ratio) and heats to 480 degrees celsius? When the fuel explodes in the compression chamber...
Sunday, May 22, 2016 by Eve

Chemistry
How to convert 4.6-10.5 micrograms/dL to nmol/L? The answer is 59-135 nmol/L, but I have no idea how to set it up to get that answer.
Sunday, May 22, 2016 by Student

Chemistry
What mass of solid magnesium hydroxide is needed to neutralize .385 L of 2.5 M nitric acid?
Sunday, May 22, 2016 by Morgan

Chemistry
What is the concentration of 127 mL of solution made with .450 g of nickel (II) nitrate hexahydrate?
Sunday, May 22, 2016 by Morgan

Chemistry
A sample of impure Limestone weighing 0.3440 g was treated with 50 mL of HCl 0.1363 mol/l. after elimination of all CO2 by boiling, excess acid was created by 4.45 mL of NaOH 0.1445 mol/L1. Calculate the% (w/w) of CaO and CaCO3 in the sample
Saturday, May 21, 2016 by Kelly

Chemistry
5 grams of H2 reacts with 16 g of O2, which in excess? 2H2(g)+O2(g)=2H2O(g)
Saturday, May 21, 2016 by Alan

chemistry
As when forming a hydroxide the ion OH is used in this manner Metal(OH)valence of metal does that mean that if my valence is 2 as with calcium,i have 2 molecules of oxygen and two of hydrogen??
Saturday, May 21, 2016 by Camila

chemistry
Name the product obtained on passing carbon iv oxide into saturated sodium trioxocarbonate (iv) solution
Saturday, May 21, 2016 by Tobasco

Chemistry
How can I make 100ml 0f 2N of HCl? purity is 35% and density is given as 1.18 g/mL
Saturday, May 21, 2016 by Anna

Chemistry
A sample of hydrogen gas (H2) is produced in a laboratory by displacement of water. A 645 mL sample of hydrogen is collected at 25 degrees Celsius and a total pressure of 758 torr. Collecting gas by water displacement causes the gas to become saturated with gaseous water vapor...
Friday, May 20, 2016 by Roger

Chemistry
Ok so I realize this is a lot of questions, but if someone could at least just give me the general set up for each problem that would save my life! In each of the four problem in this section, all gases are measured at the same temperature and pressure. 1) (a) What volume of ...
Friday, May 20, 2016 by Eve

Chemistry
Compute the approximate density of methane, CH4, at 20oC and 5.00 atm. The molecular weight of methane is 16.0.
Friday, May 20, 2016 by Eve

General Chemistry
Ferric Hydroxide, Fe(OH)3, is an insoluble salt with a solubility of 10^-39. 1) What is the maximum concentration of ferric hydroxide that can dissolve? 2) Using Le Chatalier's Principle, explain why iron (III) solutions are more soluble in acidic solution.
Friday, May 20, 2016 by Henry

Organic Chemistry
What volumes of 0.00250M salicylic acid solution and 0.1M ferric chloride solution would you need to make 50mL of a 0.00350M solution?
Friday, May 20, 2016 by Mike

Chemistry
Write the equation for the reaction of calcium and oxygen. Write the oxidation numbers for both the reactants and the products. What is the reducing agent and why?
Friday, May 20, 2016 by Carmen

Chemistry
What is the oxidation half reaction for the following equation: Cr2O7^-2 +Fe+2 - - > Cr^+3 + Fe^+3 Cr^+3 - - > Cr2O7^-2 Fe^+2 - - > Fe^+3 Fe^+3 - - > Fe^+2*** Cr2O7^-2 - -> Cr^+3
Friday, May 20, 2016 by Kayla

Chemistry
Which atom has a change in oxidation number of –3 in the following redox reaction? K2Cr2O7 + H2O + S - - > KOH + Cr2O3 + SO2 K Cr*** O S
Friday, May 20, 2016 by Kayla

science(chemistry)
How is ethanol after 1 minutes of evaporation
Friday, May 20, 2016 by Anonymous

CHEMISTRY
Chromium (III) iodate has a Ksp at 25°C of 5.0 x 10–6. 125 mL of a solution contains 0.0050 mol L–1 Cr (III) ion. If the addition of 10.0 mL of a NaIO3 solution to the Cr (III) ion solution causes precipitation to begin, what is the concentration of the NaIO3? a...
Thursday, May 19, 2016 by MC

Chemistry
Fe+o2+h2o->fe(oh)3
Thursday, May 19, 2016 by Anu

Chemistry
What is the oxidation number for each atom in NH4F? N=+3, H=-4, F=+1 N=-3, H=+1, F=-1*** N=+3, H+1, F=-1 N=-3, H=-1, F=+1
Thursday, May 19, 2016 by Holly

Chemistry
Calculate H2 Equation 1- CH4g+2O2g+CO2g+2H2OgH1=-890kj Equation 2- CH4g+O2g+CH2Og+H2OgH2=? Equation 3- CH2Og++O2g+CO2g+H20gH3=-518kj
Thursday, May 19, 2016 by Sarah

Chemistry
Equation 1- 2Ss+3O2g+2SO3gh1=? Equation 2- 2Ss+2O2g+2SO2gh3=-594kj Equation 3- 2SO2g+O2g+2SO3gh3=-198kj Use Hess's law in your own words.
Thursday, May 19, 2016 by Sarah

Chemistry
What is the reducing agent in the following reaction? 2K + S - - > K2S K S*** K2S None of the above
Thursday, May 19, 2016 by Holly

Chemistry
Consider this reaction N2g+O2g+2NOg H=180.5kj How much heat would be required to produce 1.300 mol NOg?
Thursday, May 19, 2016 by Sarah

Chemistry
In the reaction of beryllium with fluorine, which atom is oxidized? fluorine beryllium*** neither of them both of them
Thursday, May 19, 2016 by Holly

Chemistry
What are transferred in an oxidation-reduction reaction? atoms*** electrons ions protons
Thursday, May 19, 2016 by Holly

Chemistry
The reaction of 1 Mol of iron metal with 3 Mol aqueous HCI produces 1.5 mol H2 gas, 1 mol aqueous FeCI3, and 87.9 kj of heat. Write a thermochemical equation for this reaction
Thursday, May 19, 2016 by Sarah

chemistry
if a 20 ml sample of nitric acid is titrated with 32 ml of 0.200 mol of potassium hydroxide what is the concentration of the nitric acid
Thursday, May 19, 2016 by ester

Chemistry
C5H12 + O2--- CO2 + H2O give that the equation if I use 85 grams of O2 and excess C5H12 how many grams of CO2 are produced
Thursday, May 19, 2016 by Jackie

Math
At small town high there are 100 students,each of whom takes atleast one of Biology,Chemistry,or physics.There are 50 student in Biology,60 in chemistry,and 70 in Physics.If 24 students are enrolled in exactly two of the classes,how many students are in all three?
Thursday, May 19, 2016 by Luiz

Chemistry
Which electrode (anode or cathode) is designated as positive in an electrolytic cell? anode**** cathode both neither
Thursday, May 19, 2016 by Nikkie

Chemistry
Why can't a lead storage battery be recharged indefinitely? A direct current must pass through the cells. The electrodes lose lead sulfate.*** It is difficult to reverse the direction of current flow. The electrolyte is too expensive.
Thursday, May 19, 2016 by Nikkie

Chemistry
The first electrochemical cell was invented by ____. Michael Faraday Alessandro Volta*** James Maxwell Benjamin Franklin
Thursday, May 19, 2016 by Nikkie

Chemistry
Which of the following metals is oxidized by calcium ions? potassium*** zinc iron lead
Thursday, May 19, 2016 by Nikkie

chemistry
why is born haber cycle not generally used to consider the energy changes involved in the formation of solid silicon(IV)oxide SiO2
Thursday, May 19, 2016 by jay

science(chemistry)
2 mL 1.5 M naoh and 1.5 mL 2 M naoh mixed solution's concentrate=?
Thursday, May 19, 2016 by rajib

chemistry
6.0 g potassium chromate is dissolved in 20 g water at 80 degree celcius. The solution is then cooled to 0 degree celcius. What mass of solute crystallises, assuming a supersaturated is not formed?
Thursday, May 19, 2016 by viola

chemistry
Given reaction 2NH3(g) + 3Cl2(g) → N2(g) + 6HCl(g), you react 5.0 L of NH3 with 5.0 L of Cl2 measured at the same conditions in a closed container. Calculate the ratio of pressures in the container (Pfinal/Pinitial). 0.75 1.00 1.50 1.33 None of these choices are correct
Thursday, May 19, 2016 by Ha

chemistry
what is the temperature of a gas at 88 torr, if at 60 kPa the temperature is -73 degrees C?
Thursday, May 19, 2016 by anonymous

chemistry
calculate the masses of each substance formed when 10g of CaCO3 reacts with excess HCl so far I've found the ratio between the substances but from then on, I'm lost
Wednesday, May 18, 2016 by struggle

chemistry
what is the actual freezing temperature of a 0.50m aqueous solution of sodium chloride?
Wednesday, May 18, 2016 by kim

Chemistry
How much solid ammonium chloride would be needed to make 100 mL of a 0.5M solution?
Wednesday, May 18, 2016 by Katherine

Chemistry
What is the name that is given to a hydrocarbon that contains 7 carbons bonded together with 16 hydrogen atoms all with single bonds? - Heptane?
Wednesday, May 18, 2016 by Anonymous

Chemistry
Calculate the number of moles of sodium oxide, Na2O, that should be produced when 11.50 moles of sodium, Na, react with oxygen gas
Wednesday, May 18, 2016 by Zywan

chemistry
The human body is said to contain approximately 50.0 grams of DNA in the entire body. If the number of nucleotides in ONE STRAND of DNA is approximately 3.0 x 106, and the average molar mass of a nucleotide is 327 g/mol, what is the average molar mass of an entire DNA double ...
Wednesday, May 18, 2016 by jenna

Chemistry
The solubility product constant of Calcium hydroxide is 6.5 * 10^-6 . If 0.10 mo of sodium hydroxide is added to 1 L of 0.0001 M Ca(OH)2, what is the final concentration of the calcium ion? Show your work.
Wednesday, May 18, 2016 by Ian

chemistry
why does BeCl2 have low melting point but SiO4 has high melting point even though they are both covalent bonds between the atoms
Wednesday, May 18, 2016 by jay

Chemistry - Answer Check
The two common chlorides of Phosphorus, PCl3 and PCl5, both important in the production of other phosphorous compounds, coexist in equilibrium as shown in the balanced chemical reaction below: PCl3 (g) + Cl2 (g) <-----> PCl5 (g) At 250 C, an equilibrium mixture in a 2.50...
Tuesday, May 17, 2016 by Anonymous

CHEMISTRY 1B
A student finds that k = 0.0027 L/mol · s, and m and n are both 1. Calculate the expected rate if 6.0 mL of 0.10 M [S2O82− ] is mixed with 4.0 mL of 0.20 M [I − ]. Assume the final volume of the solution is 10.0 mL. I used the given molarities ...
Tuesday, May 17, 2016 by Joanaleine Ferrera

Chemistry - Answer Check
Gaseous hydrogen and iodine are placed in a closed container at 425 degrees Celsius. The reactants react to produce the gaseous compound hydrogen iodide, which partially decomposes back into hydrogen and iodine gas as shown below. H2 (g) + I2 (g) <----> 2HI (g) You are ...
Tuesday, May 17, 2016 by Anonymous

chemistry
In a constant-pressure calorimeter, 60.0 mL of 0.930 M H2SO4 was added to 60.0 mL of 0.320 M NaOH. The reaction caused the temperature of the solution to rise from 22.68 °C to 24.86 °C. If the solution has the same density and specific heat as water (1.00 g/mL and 4....
Tuesday, May 17, 2016 by Amy

Chemistry
A solution contains H2O2 in water. Complete decomposition of the H2O2 in 170 g of this solution yields 5.6 L of O2(g), measured at 0 oC and 101.325 kPa. What is the percentage by mass of H2O2 in this solution? Choose the closest answer. A 10% B 20% C 5.0% D 3.0% E 1.0%
Tuesday, May 17, 2016 by anon

chemistry
Will 12 moles of co2 or 12 moles of co have higher volume at STP?
Tuesday, May 17, 2016 by Anonymous

Chemistry
Sulfur trioxide can be produced by the reaction in the gaseous phase, sulphur dioxide with molecular oxygen in the presence of a catalyst. If 128 g branches of SO2 were placed in the presence of 16 grams of O2, that amount of SO3 will be theoretically formed?
Tuesday, May 17, 2016 by Anna

Chemistry
Determine how many grams of Al must react with 2.5 M NaOH in order to produce 40 mL of hydrogen gas at 22°C and 1.02 bar
Tuesday, May 17, 2016 by Anon

chemistry
Three bottles of aqueous solutions are discovered in an abandoned lab. The solutions are green, yellow and purple. It is known that three complex ions of chromium (III) were commonly used in that lab: [Cr(H2O)6]3+, [Cr(NH3)6]3+, [Cr(H2O)4Cl2]+. What is the likely identity of ...
Tuesday, May 17, 2016 by anonymous

chemistry
Will 2 moles of CO2 or 12 moles of CO have higher volume at STP? CO2 CO Neither
Tuesday, May 17, 2016 by Anonymous

chemistry
If 45L of methane undergoes complete combustion at 1.1atm and 95 ° F how many grams of each product are formed?
Tuesday, May 17, 2016 by Anonymous

chemistry
If you have an unknown gas at some pressure and volume is 15mL, and compress it to double that pressure isothermally, what was the original pressure and the new pressure?
Tuesday, May 17, 2016 by Anonymous

Chemistry
Find the number of mL of 4M HNO3 solution required to react with 216g of Ag according to the equation 3Ag+4HNO3->3AgNO3+2H2O
Tuesday, May 17, 2016 by tabby

chemistry
What is the ∆G for the following reaction under standard conditions (T = 298 K) for the formation of NH4NO3(s)? 2NH3(g) + 2O2(g) NH4NO3(s) + H2O(l) Given: NH4NO3(s): ∆Hf = -365.56 kJ ∆Sf = 151.08 J/K. NH3(g): ∆Hf = -46.11 kJ ∆Sf = 192.45 J/K. H2O(...
Tuesday, May 17, 2016 by Anonymous

Chemistry
What causes a reaction to be spontaneous? Answer by answering each part a) (1 point) What is definition of spontaneous reaction?b) (1 point) What is Gibbs free energy?c) (1 point) How is Gibbs free energy related to a spontaneous reaction?d) (1 point) What is an example of a ...
Tuesday, May 17, 2016 by Adam

Chemistry
The solubility product constant of Calcium hydroxide is 6.5 * 10^-6 . If 0.10 mo of sodium hydroxide is added to 1 L of 0.0001 M Ca(OH)2, what is the final concentration of the calcium ion? SHOW your work. Again, I have no idea where to start
Tuesday, May 17, 2016 by Adam

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Homework Help: Science