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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
Oxygen gas and aqueous benzoic acid react to form carbon dioxide gas and water gas. Determine the mass of water in grams if 5.43×104 milligrams of oxygen reacts with an excess of benzoic acid. I balanced the equation to 2C7H6O2+15O2=14CO2+6H2O

Chemistry
Which one of the following is NOT a physical process? A. Dry ice subliming B. Steam condensing C. Alcohol evaporating D. Melting ice E. Gold plating jewelry

Chemistry
Consider the following reaction. 2Fe2O3 --> 4Fe+3O2 Hrxn=+824.2 The Formation of 21.0 of Fe results in 1)the release of 77.5 kJ of heat. 2)the absorption of 3.10 × 102 kJ of heat. 3)the release of 4330 kJ of heat. 4)the absorption of 77.5 kJ of heat. 5)the release of 3.10...

chemistry
The ice skate of a 210-pound hockey player is in contact with the ice over a 2.5mm x 15cm area. Determine the freezing point of the ice under the blade of the skate?

chemistry
Calculate the work done (in joules) when 5.0 mole of water is frozen at 0°C and 1.0 atm. The volumes of five moles of water and ice at 0°C are 0.0900 L and 0.0980 L, respectively.

chemistry
Calculate the heat of decomposition for this process at constant pressure and 25°C. (Look up the standard enthalpy of formation of the reactant and products in the table; ΔH°f(BaCO3(s)) = -1218.8 kJ/mol, ΔH°f (BaO(s)) = -558.2 kJ/mol and ΔH°f (Na2CO3(s)) = -...

chemistry
Calculate the heats of combustion for the following reactions from the standard enthalpies of formation listed in Appendix 2. (ΔH°f (HgO(s)) = -90.7 kJ/mol and ΔH°f (FeO(s)) = -272 kJ/mol.) (a) 2 Fe(s) + O2(g) 2 FeO(s) kJ (b) 2 CH3OH(l) + 3 O2(g) 2 CO2(g) + 4 H2O(l)

chemistry
Ethanol (C2H5OH) and gasoline (assumed to be all octane, C8H18) are both used as automobile fuel. If gasoline is selling for $1.45/gal, what would the price of ethanol have to be in order to provide the same amount of heat per dollar? The density and ΔH°f of octane are 0...

Chemistry
A 2.35 g sample of a substance suspected of being pure gold is warmed to 72.2 ∘C and submerged into 15.5 g of water initially at 24.1 ∘C. The final temperature of the mixture is 26.5 ∘C. Part A What is the heat capacity of the unknown substance? Part B Could ...

Chemistry
Suppose a student diluted and titrated a bleach unknown exactly as described in the experimental procedure, except only a single titration was performed which required 12.62 mL of 0.100 M Na_{2}S_{2}O_{3} Calculate the number of moles of ClO in the sample titrated.

Chemistry
how many grams of pure uranium can theoretically be extracted from 10.0kg sample of pitchblende which is 92.0%uo2

Chemistry
What ionic compound, is the primary source of a chicken's egg? I think it is calcium carbonate? If it is thought what is the logical/ explanation behind it can someone please explain this to me. Btw what would be the chemical equations for an egg being placed in water, and for...

Chemistry
Does group 18 elements like He, Ne, Ar, Kr soluble in organic solvents?

chemistry
Calculate the freezing point of water at a depth of 10.0 cm below the surface of the water. The density of the water is 0.9998 g/cm3.

chemistry
When performing an extraction, is it better to have a higher or lower K (distribution coeffictient/ partition coefficient) value? Explain.

Chemistry-Dr.Bob
The specific rotation of pure enantiomer is known from the literature to be -20. The measured value of a solution containing A plus its enantiomer B (specific rotation must be +20) is -40. What is the ee (enantiomer excess) of this sample?

Chemistry
The specific rotation of pure enantiomer is known from the literature to be -20. The measured value of a solution containing A plus its enantiomer B (specific rotation must be +20) is -40. What is the ee (enantiomer excess) of this sample?

Chemistry
To what volume must 10ml of 5M HCl be diluted to make a 0.5M HCl solution......???? A.1ml B.50ml C.100ml D.500ml E.1000ml

Chemistry
Does group 18 elements soluble in organic solvents such as tetra-chloro-methane or alcohol

Chemistry
102.0 MHz (typical frequency for FM radio broadcasting) Express your answer using four significant figures.

Science chemistry
Also. If you are given the conductivity of an unknown chemical, what the blue and red litmus paper change into when you check the chemical. And the pH level and solution type. How do you know the solution name and formula? I never learned how to find the solutions name of ...

Science chemistry
Also. If you are given the conductivity of an unknown chemical, what the blue and red litmus paper change into when you check the chemical. And the pH level and solution type. How do you know the solution name and formula? I never learned how to find the solutions name of ...

Science chemistry
Does hydrogen borate conduct electricity? We were told to search this up but I can't find it online and my class never did a lab on it.

Chemistry
A 1.00Lgas sample at 1.00degree celsius and 600torr contain 50.0%helium and 50.0%xenon by mass. What are the partial pressure of the individual gasses?

Chemistry
What mass of Cu(IO3)2 can be formed from 0.690g of CuSO4-5H2O?

Chemistry
Consider the following reaction. CaSO4(s) reverse reaction arrow Ca2+(aq) + SO42-(aq) At 25°C the equilibrium constant is Kc = 2.4x10^-5 for this reaction. (a) If excess CaSO4(s) is mixed with water at 25°C to produce a saturated solution of CaSO4, what are the equilibrium ...

chemistry
How many grams of potassium iodide, KI, are required to make 2.0 L of a 0.1M solution?

Chemistry
A mixture of NaOH and HCl is formed in a calorimeter. There is 50 mL of 2.078 Molar HCl and 51.7mL of 2.134 Molar NaOH. How would the heat capacity of the calorimeter change if you were to double the volume of NaOH? Justify your answer

Chemistry
A good vacuum pump on Earth can produce a vacuum with a pressure as low as 1.96 × 10-8 torr. How many molecules are present in each milliliter at a temperature of 23.0ºC?

Chemistry
What is the molarity of each ion present if 18.0 g of Al2(SO4)3 is present in 201 mL of solution? _____ M Al3+ _____M SO42-

Chemistry
What is the molarity of each ion present if 18.0 g of Al2(SO4)3 is present in 201 mL of solution? _____ M Al3+ _____M SO42-

Chemistry
In the reaction of formation of sodium chloride (NaCl), 15 g of sodium is placed in contact with 20 g of chlorine. What is the reactant in excess and its mass in excess?

Chemistry
A solution of NaOH(aq) contains 5.4 g of NaOH(s) per 100.0 mL of solution. Calculate the pH and the pOH of the solution at 25 °C.

college chemistry
using cu+2AgNo3= Cu(No3)2 + 2Ag if you start with 100 grams of copper how many grams of silver can be obtained

chemistry
Consider these reactions where M represents a generic metal 1. 2M(s) +6HCl(aq) --> 2MCl3(aq)+3H2(g) (deltaH)= -725.0 kj 2. HCl(g)-->HCl(aq) (deltaH)= -74.8kj 3. H2(g)+CL2(g) --> 2HCl(g) (deltaH)=-1845.0kj 4. MCL3(s) --> MCl3(aq) (deltaH)= -476.0kj Use the ...

chemistry
Given these reactions : X(s) + 1/2O2(g) --> XO(s) (Delta)H= -707.7 kj XCO3(s) --> XO(s)+CO2(g) (Delta)H= +381.9kj What is (delta)Hrxm for this reaction? X(s)+1/2 O2(g)+CO2(g) ---> XCO3(s) (Delta)H= ?

chemistry
Calculate the standard enthalpy change for the following reaction at 25 °C. H2O+C(graphite)(s) --> H2(g) +CO(g)

chemistry
The following equation is the balanced combustion reaction for C6H6: 2C6H6(L) + 15O2(g) --> 12CO2(g)+6H2O(L)+6543 kj If 7.700 g of C6H6 is burned and the heat produced from the burning is added to 5691 g of water at 21 °C, what is the final temperature of the water?

chemistry
If the heat of combustion for a specific compound is -1180.0 kJ/mol and its molar mass is 40.91 g/mol, how many grams of this compound must you burn to release 114.50 kJ of heat?

chemistry
A 2.50-g sample of powdered zinc is added to 100.0 mL of a 2.00-M aqueous solution of hydrobromic acid in a calorimeter. The total heat capacity of the calorimeter and solution is 448 J/K. The observed increase in temperature is 21.1 K at a constant pressure of one bar. Using ...

chemistry
When a 8.00-g sample of KBr is dissolved in water in a calorimeter that has a total heat capacity of 3.344 kJ·K–1, the temperature decreases by 0.400 K. Calculate the molar heat of solution of KBr.

chemistry
A researcher studying the nutritional value of a new candy places a 4.10-gram sample of the candy inside a bomb calorimeter and combusts it in excess oxygen. The observed temperature increase is 2.47 °C. If the heat capacity of the calorimeter is 33.90 kJ·K–1, how many ...

chemistry
At constant volume, the heat of combustion of a particular compound is –3947.0 kJ/mol. When 1.311 g of this compound (molar mass = 136.58 g/mol) was burned in a bomb calorimeter, the temperature of the calorimeter (including its contents) rose by 4.343 °C. What is the heat ...

chemistry
Liquid sodium is being considered as an engine coolant. How many grams of liquid sodium (minimum) are needed to absorb 7.00 MJ of energy (in the form of heat) if the temperature of the sodium is not to increase by more than 10.0 °C? Use CP= 30.8 J/(K·mol) for Na(l) at 500 K.

chemistry
When 1367 J of heat energy is added to 44.1 g of hexane, C6H14, the temperature increases by 13.7 °C. Calculate the molar heat capacity of C6H14.

chemistry
An 80.0-gram sample of a gas was heated from 25 °C to 225 °C. During this process, 346 J of work was done by the system and its internal energy increased by 8305 J. What is the specific heat of the gas?

chemistry
If you combine 360.0 mL of water at 25.00 °C and 120.0 mL of water at 95.00 °C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water.

Chemistry
A solution of concentrated NaOH is 16.7M. If the density of the solution is 1.02 g/mL, what is the percent by mass of NaOH? I have tried different calculations and molarity and % but im not catching on at all

Chemistry
A solution of concentrated NaOH is 16.7M. If the density of the solution is 1.02 g/mL, what is the percent by mass of NaOH? I have tried different calculations and molarity and % but im not catching on at all

organic chemistry
inversion of S configuration to R configuration?????

Chemistry
Please write down the redox reactions (using the half-reaction method!) a)Cl2 from OCl- and Cl- in acidic solution b)Br2 from BrO3- and Br- in acidic solution -You don't have to do both, but could you help me step up the half reactions especially for OCl- --> Cl2

chemistry
An 80.0-gram sample of a gas was heated from 25 °C to 225 °C. During this process, 346 J of work was done by the system and its internal energy increased by 8305 J. What is the specific heat of the gas?

Chemistry
How much sulphuric acid containing 90% H2SO4 by wt. is needed for the production of 1000 kg of HCl containing 42% HCl by weight in this reaction. 2NaCl + H2SO4 -----> Na2SO4 + 2HCl

chemistry
Liquid sodium is being considered as an engine coolant. How many grams of liquid sodium (minimum) are needed to absorb 7.00 MJ of energy (in the form of heat) if the temperature of the sodium is not to increase by more than 10.0 °C? Use CP= 30.8 J/(K·mol) for Na(l) at 500 K.

chemistry
When 1367 J of heat energy is added to 44.1 g of hexane, C6H14, the temperature increases by 13.7 °C. Calculate the molar heat capacity of C6H14.

chemistry
In a constant-pressure calorimeter, 60.0 mL of 0.300 M Ba(OH)2 was added to 60.0 mL of 0.600 M HCl. The reaction caused the temperature of the solution to rise from 21.75 °C to 25.84 °C. If the solution has the same density and specific heat as water (1.00 g/mL and 4.184 J/g...

Chemistry
Consider a mole of gas obeying the equation of state P⋅V = n⋅R⋅T + n⋅B(T)⋅P. Find w, q, ΔU, ΔS, ΔH, ΔA, and ΔG for a reversible isothermal expansion of this gas. Express your answers in terms of initial and final pressures...

chemistry
An 80.0-gram sample of a gas was heated from 25 °C to 225 °C. During this process, 346 J of work was done by the system and its internal energy increased by 8305 J. What is the specific heat of the gas?

chemistry
If you combine 360.0 mL of water at 25.00 °C and 120.0 mL of water at 95.00 °C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water.

Chemistry
How many grams of H2O are required to react with excess CaC2 to produce 23.0 g of C2H2 according to the following equation? CaC2 + 2H2O -> Ca(OH)2 + C2H2 a.4.5 b.15.9 c.31.8 d.1.766 I think this equation works out by multiplying 2 moles by the molar mass of H2O. Please ...

Chemistry
If 3.60 moles of SiO2 and 3.60 moles of C react to form SiC accodring to the equation SiO2 + 3 C -> SiC + 2 CO how many moles of CO will be produced? a. 1.20 b.2.40 c.3.60 d.7.20 -Do I have to use SiC in any part of the equation, I am very confused and I think I just need ...

Chemistry
Methane, CH4 is the main component of natural gas which is used for cooking in many homes. The molar heat of combustion of methane is -890kj/mol. A cook wants to boil some water on a gas stove. If the stove burns 5.00g of methane to heat 2575 ml of water, what is the ...

Chemistry
My question talks about a buffer with HA and NaA, where NaA is the sodium salt of the acid. What does the equation for this look like? HA + NaA --> H+ + NaA2 ??

Chemistry
The principal quantum number (n): (1) specifies the subshell of the orbital. (2) specifies the principal shell of the orbital. (3) specifies the 3-D shape of the orbital. (4) specifies the maximum number of electrons. (5) none of the above

Organic Chemistry 1
Consider the HF solution with the concentration of 5%(w/v). You can convert the % concentration into the molarity. a) Assume that you have 100ml of this solution. Determine the number of moles of HF if the concentration of HF is given as 5%(w/v) For this part I did 5% is 5g ...

Organic Chemistry 2
The typical % yield for the reduction of 9-fluorenone using NaBH4 to obtain 9-fluorenol is 80%. In my experiment I obtained 89 %. Can you explain the reasons why my yield is higher? Is it better to obtain a higher yield or a lower yield than the expected one?

chemistry
A student determines the heat of dissolution of solid potassium perchlorate using a coffee-cup calorimeter of negligible heat capacity. When 2.13 g of KClO4(s) is dissolved in 106.00 g of water, the temperature of the solution drops from 25.00 to 23.17 °C. Based on the ...

Chemistry
Draw the product(s) of the following reaction CH3-CH2-C(triple bond)C-CH2 ---------> ? (Na/NH3)

Chemistry
Define electronegativity and then describe the trends in electronegativity within groups and across periods in the periodic table. Provide examples of the elements with the highest electronegativity value within a group and an example of an element with the highest energy ...

Chemistry
A fictitious element X is composed of 78.0% of the isotope X-50, 15.0% of the isotope X-51 , and 7.0% of the isotope X-52. Estimate the atomic mass of element X. Show your work.

Chemistry
why are most elements on the periodic table found as compound in nature?

CHEMISTRY
WRITE A BALANCE EQUATION BETWEEN PHOSPHORIC ACID AND SODIUM HYDROXIDE USING METHYL ORANGE

Chemistry
How to find mmol? this is for dilantin by multistep synthesis lab. using 350 mg of benzoin = mmol? using 160 mg NH4NO3 = mmol?

Chemistry
The solubility of KI in ethyl alcohol is 2.00 grams of KI in 100.0 grams of this alcohol. From this information, calculate the molarity of this solution.

AP Chemistry
A typical bathtub can hold 94 gallons of water. Calculate the mass of natural gas that would need to be burned to heat the water for a tub of this size from 59 ◦F to 101 ◦F. Assume that the natural gas is pure methane (CH4) and that the products of combustion are ...

Chemistry
A gallon of isopropanol (IPA) weighs 6,55 lbs. Since 1 lb=453.6 grams, calculate how many moles of ethanol (MM=60.1 grams per mole) are in a gallon of this substance.

Chemistry
What is the standard concentration of FeSCN^2+ if 18mL of 0.200M Fe(NO3)3 were combined with 2mL of 0.0020M KSCN?

Chemistry
20cm3 of 0.1m sulphuric acid was required to react with 50.0cm3 of a solution of sodium hydroxide

Chemistry
Standardization of iodine solution was prepared using 10.0 mL of a standard, 1.00 mg/mL, ascorbic acid solution. Titration with the iodine solution required 35.80 mL to reach the end point. What is the molarity of the iodine solution?

Chemistry
Homework question? Colmanite [Ca2B6O11 * 5 H20] is a salt whose boron content gives glass high clarity. You are a buyer for an optical fiber manufacturer and want pure material. You have just received a Certificate of Analysis for a lot that is 12.8 +- 1.2% (i.e;11.6 to 14.0...

Chemistry
Note- I do not want the answers. I just need to know how to set up each.. The combustion of isopropyl alcohol (Molar Mass=60.1 g/mole) is described by the following balanced equation: 1 C2H8O + 9 O2 (g) -> 6 CO2 (g) 8H2O (l) + 4012 kJ of heat energy a) How much heat energy ...

Chemistry
What is the mass of water produced when 5 moles of hydrogen burn in the presence of excess oxygen?

Chemistry
Some pieces of jewelry react with compounds in sweat. The reaction can leave stains on your skin. Not all jewelry has this effect. Use the activity series of metals to explain this observation. please help

Chemistry
A certain mixture of helium, He, and krypton, Kr, has a mass of 10.0 g and occupies a volume of 20.0 L at 25.0EC and 1.20 atm. What is the mass of He in the mixture?

Chemistry
describe the preparation of 12 mL of a 0.050 M solution of each of the halogens, using the reactions in the preceding question. Available to you are solid Ca(OCl)2; 0.20 M solutions of NaCl, NaBr, NaBrO3, and CuSO4; a 0.40 M solution of NaI; a 0.50 M solution of H2SO4; ...

Chemistry
In a three reactions system the first two reactions are endothermic with DeltaH values of 138kj and 241kj. if the final reaction is exothermic what is the minimum value of DeltaH3 that would make the overall reaction exothermic? explain your reasoning. i beleive the minimum ...

Chemistry
Silicon carbide (SiC) is made by reacting sand (Silicon dioxide, SiO2) with powdered carbon at high temperature. Carbon monoxide is also formed. What is the percent yield if 51.4kg of SiC is recovered from processing 100.0kg of sand? What mass (in kg) of carbon would be needed...

chemistry
Calculate the molarity of 12.5g of sucrose (C12H22O11) in 80mL of solution. 12.01 x 12 = 144.12 1.01 x 22 = 22.22 16.00 x 11 = 176.00 ------------------- 342.34 12.5g ----- / 342.34 = 0.003/80 = 4.56 80mL

chemistry
For each pair of compounds, predict which species will have the higher molar entropy at 298 K and 1 bar. Be sure to state your reasons for your choice. 1. N2(g) vs. F2(g) 2. ICl (g) vs. BrF(g) 3. 6Li(s) vs. 7Li(s

Chemistry
How to prepare 250ml of 2.5m solution of HCL

Chemistry
What is the solvent in70% of alchol solution?

chemistry
Calculate the mass of oxalic acid needed to prepare 150 ml of 0.442 M C2H2O4.

Sciene ( Chemistry )
The heat of neutralisation of LiOH and HCL at 25 degree celsius is 34.868 kJ/mol.The heat of ionisation of LiOH will be ?

Chemistry
What is NaOH?

chemistry
What is the wavelength of radiation whose frequency is 5.93 x 10^14 s-1

Chemistry
A 250 g mass of material has a temperature of –45˚C. Its specific heat is 0.36 J/gˑ˚C. How much heat energy is required to raise its temperature to 10˚C? (its melting point is 23 ˚C)

Chemistry
Calculate the mass of water produced when 9.53 g of butane reacts with excess oxygen

Ap chemistry
Calculate the concentrations of all ions present in the following solutions of strong electrolytes : 2.0 times 10-3 M AL2(SO4)3

Chemistry pH, acids, and bases
Trichloroacetic acid (CCl3CO2H) is a corrosive acid that is used to precipitate proteins. The pH of a 0.050 M solution of trichloroacetic acid is the same as the pH of a 0.040 M HClO4 solution. Calculate Ka for trichloroacetic acid. I just don't know where to start. How can ...

Chemistry - acids & bases
4. Calculate the pH of each of the solutions and the change in pH to 0.01 pH units caused by adding 10.0 mL of 2.37-M HCl to 320. mL of each of the following solutions. Change is defined as final minus initial, so if the pH drops upon mixing the change is negative. c) 0.115 M ...

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