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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
2KCLO3+heat makes 2KCL+3O2 is it endothermic or exothermic

2017 chemistry practical
the titre I am obtaining in the titration of hydrochloric acid against sodium trioxocarbonate (iv) decahydrate is out of range.(42.40cm3). How should I go about it?

Chemistry
C4H6O2 a) Draw a plausible structure for this compound that contains alcohol, ether, and alkyne functional groups. b) Draw a plausible structure for this compound that contains aldehyde and ketone functional groups.

Chemistry
Indicate which elements can be used as potential semiconductors, and which ones can be used as potential dopants used to make n-type and p-type semiconductors by placing them in the corresponding bin. F, Al, As, Ge, I. p-type semiconductors can consist of: a)highly purified ...

Chemistry
If I have 42g of NaCl how many moles of NaCl do i have?

Chemistry
In a coffee cup calorimeter, 2.00 g of potassium hydroxide are mixed with 200.0 g of water at an initial temperature of 25.00C. After dissolving the salt, the final temperature of the solution is 27.33C. What is the heat change for the dissolution of potassium hydroxide ...

Chemistry
Thirty feet of water exert a pressure of 1 atm. Calculate the pressure (in kPa) exerted on a diver at a depth of 50 feet on a standard day.

Chemistry
A 30 g sample of water at 280 K is mixed with 50 g water at 330 K. Calculate the final temperature of the mixture assuming no heat loss to the surroundings.

chemistry
A 3.04 g piece of aluminum at 60.0 °C is placed into a “styrofoam cup” calorimeter filled with 150.0 mL of water at 25.0 °C. What is the final temperature of the contents of the calorimeter once thermal equilibrium has been established (everything has the same final ...

Chemistry
What is the subshell designation for an electron with the following set quantum numbers? 1) n = 1; l = 0 2) n = 3; l = 2; mi = -1 3) n = 4; l = 3 3) n = 2; l = 0; mi = 0

Chemistry
How many orbitals are available with the following combination of quantum numbers? 1) n = 2; l = 0 2) n = 3; l = 2 3) n = 4; l = 3 I have figured that it is 1) 2s 2) 3d 3) 4f but i don't know what to do after this.

Chemistry
How many different f orbitals are there?

Chemistry
A metal foil has a threshold frequency of 5.45 x 10^14 Hz. Which color of visible light will not eject electrons from this metal? a) blue b) indigo c) violet d) orange c=(wavelength)(v) 3.0x10^8m/s = (wavelength)(5.45 x 10^14 Hz) 550 nm -> releases green. So, I am guessing ...

Chemistry
A 32 W (1 W = 1 J/s) lamp generates violet light at a wavelength of 420 nm. How many photons of this light will the lamp generate in 2.0 s?

Organic Chemistry
If one gram of aspirin is dissolved in 100mL of water at 37 degrees celsius, how much aspirin will precipitate out of solution when it is cooled to 25 degrees celsius?

Chemistry
Will a photon of light of wavelength 480 nm excite an electron in the hydrogen atom from the n = 1 level to the n = 2 level? How would I figure this out?

chemistry
2NO2(g)⇌N2O4(g). ΔH∘f for N2O4(g) is 9.16 kJ/mol.

Chemistry
An electron initially in the n = 2 energy level in a hydrogen atom absorbs a photon of light with a frequency of 6.167 x 1014 s-1. Calculate the new energy level the electron will occupy. I am not sure how to being.

chemistry
what is 1.79 x 10^-20 in kJ/mol?

chemistry
It takes 445.76 J of heat to increase the temperature of a 50.0 g piece of metal from 20.0 °C to 65.0 °C. What is the specific heat capacity of the metal (assuming the phase doesn\'t change)? Also please show work

Chemistry Heat
4Fe + 3O2 ---> 2Fe2O3 Delta H -1652 kJ How much heat is released when 10 g Fe and 2 g O2 are reacted.

Chemistry
So Ag+ + Cl- ---> AgCl and delta H is -65.5 kJ. I'm supposed to calculate delta H when one mole of AgCl dissolved in water, so 1 mol AgCl *(65.5 kJ/1mol Agcl) right? But the answer is 65.5 kJ, and why is it positive, not negative, is my question.

Chemistry
The reaction Fe + Br2 ---> FeBr2 Delta H = -249.8kJ Calculate delta H when 10.0 g of FeBr2 is formed.

CHEMISTRY
How many liters of chlorine gas at 25C and 0.950 atm can be produced by the reaction of 24.0 g of MnO2 with hydrochloric acid? The products include manganese (II) Chloride, water, and chlorine.

Chemistry
I am completely lost with this question. If 50 ml of 0.5M HCl is added to 800 ml of pure water, what will be the approximate pH of the resulting solution?

Chemistry
You want to make 40 mL of gas from some aluminum carbonate. The temperature of the lab is 23 C and the rpessure is 760 torr. If you collect the gas over water, what mass of reactant is necessary?

Chemistry
What volume of gas can be produced in a lab where pressure is 16.0 psi and temperature is 25 C if you collect it over water from the reaction of 50g of ammonium sulfate with 50g of aluminum hydroxide. The equation for the reaction is: 3(NH4)2SO4 + 2Al(OH)3 ---> Al2(SO4)3 + ...

Chemistry
What mass of zinc would need to react with hydrochloric acid in order to produce 25.0 mL of hydrogen gas collected over water at 25 degrees celsius and 105 kPa. How do you solve this using the combined gas laws? The answer is 0.067 grams but how do you get there?

Chemistry
calculate the volume occupied by 7g of N2 gas at 27 degree c and 750mm Hg pressure

Chemistry
Consider two flasks. What are the final partial pressure of H2 and N2 after the stopcock between the two flasks is opened? Assume the final volume is 3.00 L. What is the total pressure in torr? Flask 1: 2.00 L H2, 475 torr Flask 2: 1.00 L N2, 0.200 atm Imagine two round flasks...

chemistry
A balloon is filled with hydrogen gas. reaction is Fe(s) + H2SO4(aq) ----> FeSO4(aq) + H2(g). The volume of the ballon was 4800 m cubed and the loss of hydrogen gas during filling was estimated at 20.% What mass of iron splints and 98% by mass H2SO4 were needed to ensure ...

chemistry
A researcher put 10.0 moles of N2O into a 2-L container at some temperature where it decomposes according to the following: N2O = 2N2+ O2. At equilibrium 2.20 moles of N2O remain. Calculate the Kc for the reaction. How am I supposed to fill in the ICE chart if Kc isn't given ...

Chemistry
What volume will 11.2 grams of H2 gas occupy at 25.1oC and a pressure of 758 mmHg?

Chemistry please help!
Calculate (triangle)H for the following gas-phase reaction: 2 H-C (3dashes) C-H + 5 O=O --> 4 O=C=O = 2 H-O-H -Using bond energies

Chemistry Homework
Hello! Could someone help me with this? I'm confused on what to do. Thanks!! The mole fraction of carbon dioxide (CO2) in water is 0.25. Determine the molarity of CO2. The density of the solution is 1.0 g/mL.

chemistry
what is the % (m/m) of Mg(NO3)2 in solution when 0.84 g of Mg(NO3)2 are dissolved in enough deionized water to prepare 500.0 ml of solution ( assume the solution in dilute enough that the density of the solution is 1.0 g/ml)

Chemistry
What will be the final temp. of the solution in a coffee cip calorimeter if a 50.00mL sample of 0.250 M HCL is added to a 50.00 mL sample of 0.250. The initial temp. is 19.50 °C and the Delta H is -57.2 Kj/mol NaOH assume density of solution is 1.00 g/mL and specific heat of ...

Chemistry
Aluminum is produced by the electrolysis of aluminum oxide (Al2O3, bauxite ore) dissolved in molten cryolyte (Na2AlF6). Calculate the mass of aluminum that can be produced in one day in an electrolytic cell operating continuously at 1.0 x 105 amps. The cryolite does not react

MATH
Jenny is running an experiment for organic chemistry class. She needs exactly 100 ml of 70% hydrochloric acid, but the lab only has 90% and 40% solutions. How much of each solutions does she need to mix in order to obtain 100 ml of 70% hydrochloric acid solution?

chemistry
Draw a well diagram of the set up of the aparatus that can be used to show that ammonia gas can burn in oxygen Write the equation for combustion of ammonia In oxygen PLEASE HELP MI TO ANSWER THAT QUESTION IT DEFEATED MI

Chemistry
The functional group contained in the compound O || CH_3-C-O-CH_3 is a(n). A)carboxy B)amine C)ester D)amide

Chemistry
The equilibrium constant is equal to 5.00 at 1300K for the reaction 2SO2(g) + O2(g) <--> 2SO3(g) if initial concentrations are [SO2] = 6.00M, [O2] = 0.45M, [SO3]= 9.00M, the system is a/. At equilibrium b/. Not at equilibrium and will remain in an un equilibrated state c...

chemistry
How many milliliters of an aqueous solution of 0.238 M magnesium bromide is needed to obtain 9.01 grams of the salt?

Chemistry
Assume you are performing the calibration step and you begin with 70 g of water at 20*C and 70 g of water at 80*C. After adding the two portions of water into your calorimeter setup and following the procedure outlined in the experiment, you determine the temperature of the ...

Chemistry
Consider the following decomposition reaction of ammonium carbonate ((NH4)2CO3): (NH4)2CO3 (s)  2 NH3 (g) + CO2 (g) + H2O (g) In one experiment at 25.0°C, a sample of pure (NH4)2CO3 is placed in an evacuated 2.00 L vessel. At equilibrium, the total pressure is found to be ...

Chemistry
PLEASE HELP! Consider the following galvanic cell: Ag(s) | Ag+(aq) || Cu2+(aq) | Cu(s)? Match the components with their function in the cell. 1. | 2. || 3. Ag(s) | Ag+(aq) 4. Cu2+(aq) | Cu(s) A. Cathode Half Reaction B. Phase boundary C. Salt Bridge D. Anode Half Reaction

Chemistry
For the galvanic cell that uses the reaction 2 Al(s) + 3 Ni2+(aq) → 2 Al3+(aq) + 3 Ni(s) the value of n in the relationship ΔG° = -nFE° is ________.

chemistry
Calcium is determined gravimetrically by precipitating it as CaC2O4â‹… H2O, followed by isolating the precipitate as CaCO3. The sample to be analyzed is dissolved in 10 mL of water and 15 mL of 6 M HCl. After dissolution, the resulting solution is heated 24 to boiling, ...

chemistry
Aluminum can be determined gravimetrically by precipitating as Al(OH)3 and isolating as Al2O3. A sample containing approximately 0.1 g of Al is dissolved in 200 mL of H2O and 5 g of NH4Cl and a few drops of methyl red indicator is added (methyl red is red at pH levels below 4 ...

science (chemistry)
consider the following reaction AgNO3+KBr=AgBr+KNO3 calculate the amount of presipitate in gram obtained when 0.25 mole of AgNO3 is trheated with excess of aqueous KBr solution

Chemistry
Nitrogen monoxide reacts with chlorine gas according to the reaction: 2NO (g) + Cl2 (g) ⇔ 2NOCl (g) Kp = 0.27 at 700 K A reaction mixture initially contains equal partial pressures of NO and Cl2 . At equilibrium, the partial pressure of NOCl is 115 torr. What were the ...

chemistry
So we did an experiment where we mixed Cacl2 and NaCl and then found the mass of the precipitate. Then we compared it to reference data on a standard curve to see the mass of Na2Co3 reacting to produce the CaCo3. So what I'm stuck on is this: Suppose the precipitate formed in ...

Chemistry
What is the Pb2+ concentration in a saturated solution of PbCl2 if the concentration of chloride ion is 0.023 M? Units: M ksp = 1.72x10^-5 i can't seem to get the answer. i have tried and ICE diagram and going from there: PbCl2 (s) <--> Pb ^2+ = 2Cl- I: 0.023 M = Cl- C: ...

Chemistry
Please help. I have tried this a few different times and have come up with the same answer. What is the pH of the solution if 0.01 of HCl is added to a buffer containing 0.013 mol of RCOOH and 0.035 mol of RCOONa (source of RCOO-)? Ka = 2.7E-5 so far i have tried the following...

Chemistry
I'm not sure how to do these and when I looked it up, maybe there was a diff. vocab used. Please help! 1.) How do you do atom/ion inventory of : Cu3(PO4)2 A. _____ formula units Cu3(PO4)2 B. _____ atoms Cu C. _____ atoms P D. _____ atoms O E. _____ ions Cu2+ F. _____ ions PO43...

Chemistry
How many moles of benzoic acid, a monoprotic acid with Ka=6.4×10^-5, must dissolve in 250mL of H2O to produce a solution with pH=2.04

Chemistry
The Ksp for Fe(OH)3 is 1.6x10-39. Calculate the concentration of OH- if the concentration of Fe3+ at equilibrium is 0.0050M in an aqueous saturated solution of Iron(III)hydroxide.

chemistry
how can I calculate the limiting reactor in a reaction?

Chemistry
How many moles of Fe(OH)2 will dissolve in 1.00L of water buffered at pH = 12.00? Fe(OH)2 has Ksp = 1.8 × 10^-15. How would I do this? Should I make an ice table? I know the pOH = 2.00.

Chemistry
You are approaching a stoplight. If the frequency of the light being emitted is approximately 520 THz, what was the wavelength of the light? What color was the light? v = c/λ 520 THz --> 5.2x10^14 Hz 5.2x10^14 Hz = 3.0x10^8 m/s λ = 1.56 x 10^23 m Not sure how to get the ...

Chemistry
What is the energy of a photon in J emitted by the transition from the ni = 4 to the nf = 2 of a hydrogen atom?

chemistry
A 6.0-L flask contains 0.60 g at a temperature of 25°C. What is the pressure (in atm) inside the flask?

Chemistry
A 150ml solution of 0.340M HCl is mixed with a solution of 340ml of 0.175M HNO3. The solution is then diluted to a final volume of 1.00L. How many moles of H+ are present in the final solution?

Chemistry
After the initial 1 mL of 0.2 M FeCl3 (aq) and 1 mL of 0.2 M KSCN (aq) were combined it was then diluted with an additional 130 mL of deionized water. Which way would this dilution cause the equilibrium to shift? Is a dilution going to be a stress in all situations?

Chemistry
A 10.00 g strip of zinc metal is placed in 100. mL of 0.250 M silver nitrate solution. When the reaction that occurs finally ceases, what will be the mass of unreacted zinc metal in the strip? What will be the mass of silver metal that “plates out” of solution (that is, ...

Chemistry
Based on the following observations for 3 unidentified metals (Z, X, and D) and solutions of their metal cations (Zn+ and En+), rank the metals in terms of reducing agent strength, from lowest to highest. -When metal X is placed in an aqueous solution of En+, a dark residue ...

Chemistry (science)
Which compound is likely to have a lower melting/boiling point?Hydrochloric acid or Potassium sulfate? Justify. Now I know that hydrochloric acid has the lower melting and boiling point because it is covalent and potassium sulfate has an ion-ion force acting on it. But the ...

Chemistry
Sup fam, why is SO2 a stronger reducer than Cr3+?

Chemistry (science)
how does the compound type (ionic, polar, non-polar) correlate to its properties (melting/boiling points)? I have a feeling it's something related to the forces acting on them but I'm confused around how.

Chemistry (science)
how does the compound type (ionic, polar, non-polar) correlate to its properties (melting/boiling points)? I have a feeling it's something related to the forces acting on them but I'm confused around how.

Chemistry
The spectrophometer was used to measure the absorbance of each of a series of [FeSa]+ solutions. A standard curve was construnceted by plotting the absorbance vs. concentration (M). The slope and y-intercept were found to be 1496 M-1 and .003, respectively. An aspirin sample ...

Chemistry
Based on the following information, estimate the Ksp of silver bromide at 25°C. Ag+(aq) + e– → Ag(s) E° = 0.80 V AgBr(s) + e– → Ag(s) + Br–(aq) E° = 0.07 V (1) 5 x 10–13 (2) 2 x 10–25 (3) 2 x 10–15 (4) 4 x 10–30 (5) 3 x 10–11 I understand the answer is 1...

chemistry
If you have A + C <--> C + D, and you increase the concentration of A; that means equilibrium will shift to the right. Now does that also mean that concentration of C decreases?

Chemistry
What initial concentration of Cd2+ is required to result in a cell potential of 0.200 V in a voltaic cell constructed by connecting a nickel electrode that is dipped into 1.00 M NiSO4 solution to a cadmium electrode that is dipped into a solution containing the Cd2+ ions?

Chemistry
How many g of KCl are need to make 2.5 L of a 10% (w/v) solution?

chemistry
How many g of NaOH is needed to make 300.0 mL of a 20 % (w/v) solution? please please show all work I'm very lost

chemistry
When iron(ii)hydroxide is mixed with phosphoric acid, iron(ii)phosphate precipitate results. b)if 3.2g of Fe(OH)² is treated with 2.50g of phosphoric acid, what is the limiting reagent and what is the reactant in access? c)How many grams of Fe³(PO⁴)² precipitate can be ...

Chemistry
How many g of NaOH is needed to make 300.0 mL of a 20 % (w/v) solution? I'm so lost right now I have absolutely no clue

Chemistry
Let's say equilibrium shifts to the right, producing more product. I know that that increases products, but does it decrease reactants? Thanks.

Chemistry
In the reaction,C2H4(g) + 3O2(g) =2H2O(g) + 2CO2(g),what is the complete combustion of 12.5cm3 of ethene

Chemistry
Ammonia is often formed by reacting nitrogen and hydrogen gases. How many liters of ammonia gas can be formed from 17.2 L of hydrogen gas at 93.0°C and a pressure of 45.8 kPa??

chemistry
1. In the Thermodynamics of Borax Dissolution experiment, a student quickly transferred a 5.00 mL sample of the saturated borax solution into an Erlenmyer flasks using a pipet and pipet pump after the borax solution had cooled to 35oC. The student rinses the pipet with warm ...

Chemistry
How much oxygen (in grams) will form from 44.2 mg of N2O5? 2N2O5(s) → 4NO2(g) + O2(g) ____× 10^-3(g) O2

Chemistry
A 200-mL solution of KCl(aq) was electrolyzed for 10.0 minutes, producing Cl2 gas at the anode and H2 gas at the cathode. If the pH of the final solution was 12.40, what was the average current (in amps) used?

Chemistry
What is the pressure of a fixed volume of hydrogen gas at 38.8°C if it has a pressure of 1.36 atm at 15.0°C?

Chemistry
How do you prepare 17.2cm³ of 36% conc HCL per dm³ of solution?

chemistry
3. Determine the pH if 0.02 mol of NaOH is added to 1.0L of the buffer described in question #1. question1: 1. How many grams of NaHCO3 should be added to one liter of 0.100 M H2CO3 (Ka = 4.2 x 10-7) to prepare a buffer with pH = 7.00?

chemistry
2. Determine the pH if 0.02 mol of HCl is added to 1.0 L of the buffer described in question #1 question1: 1. How many grams of NaHCO3 should be added to one liter of 0.100 M H2CO3 (Ka = 4.2 x 10-7) to prepare a buffer with pH = 7.00?

chemistry
lactic acid is the avid responsible for the sour test in spit milk. on the basis of combustion analysis, it's percentage composition by mass is 40.00% carbon, 6.71%hydrogen and x% oxygen. a. Calculate the empirical formula of lactic acid b. The molar mass of lactic acid is 90g...

Chemistry
3.65 g of HCl are dissolved in 2lit of the solution find the polarity

Chemistry
For the galvanic cell that uses the reaction 2 Al(s) + 3 Ni2+(aq) → 2 Al3+(aq) + 3 Ni(s) the value of n in the relationship ΔG° = -nFE° is ________.

Chemistry
In the laboratory, a student adds 57.6 mL of water to 10.9 mL of a 0.755 M perchloric acid solution. What is the concentration of the diluted solution ?

Chemistry
How many ml of HCl required to prepare 5% of HCl solution in 750ml water.if HCl is 36% pure and specific gravity is 1.18g/ml?

chemistry
The pH or acidity of liquid is measured in pH, where pH is given by the equation pH=- log C, with C being the concentration of [H+] in multiples of M=1mol/L. Suppose you are given a solution of hydrochloric acid with a pH of 1.7 and asked to increase the pH solution by 1.4. ...

Chemistry
Given the balanced equation: H2 + Cl2 → 2 HCl , how many moles of HCl will be produced if 18.4 g H2 reacts with 127 g Cl2?

chemistry need help so bad seriously help plz
Use Rydbuz equation to calculate the wavelength of the third line in the paschen series of the hydrogen spectrum.give ur answer in Nm. RH=2.18 * 10^-18j, H=6.63 * 10^-34J. Plz help m

chemistry
Describe how you would determine the melting point of a salt of benzoic acid with melting point of 170°c

Chemistry
A solution is labeled 0.450m hcl. What is the h+ for the solution?

Chemistry
what is the balanced equation for Sodium Hydroxide and Water

Chemistry
Use the Henderson Hasselbalch equations to solve for the Ka of the acid. Solution [HX]=0.200M and [NaX]=0.200M. They both have a pH of 4.11.

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