# Homework Help: Science: Chemistry

## Recent Homework Questions About Chemistry

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 ...

Chemistry
What is the pH of distilled water supersaturated with CO2 at 100psi?

Science (Chemistry) (Yield)
Using your mass of Mg (0.101g), and assuming all of the Mg burns in oxygen and forms the theoretical predicted product, calculate the theoretical yield of magnesium oxide. I wrote out the equation and it turned out to be: 2Mg+O2->2MgO I have my mass of Mg but how do I get ...

Chemistry
SO CONFUSED PLEASE HELP!!! A certain radio wave has a wavelength of 7 inches. a. convert the wavelength of this radio wave into meters. (1 meter = 39.37) b. find the frequency of this radio wave.

Chemistry
Illustrate how to prepare a 1:3 solution of 0.5M hydrochloric acid

Chemistry
calculate the volumes of acetone and ethanol that was used to mix together in order to produce 1 litre (1000ml) of equimolar mixture. helpful notes are, ethanol Mr=46 and a density (20 degrees C)=0.789g/ml, acetone Mr=58 and density (20 degrees C)=0.793g/ml

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
How much heat (in kilocalories) is evolved or absorbed in the reaction of 1.60 g of Na with H2O? 2Na(s)+2H2O(l)→2NaOH(aq)+H2(g), ΔH = -88.0 kcal (-368 kJ)

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
0.4 moles ofpcl3 and 0.3 moles of pcl3 added to access ofC2H5OH then maximum no of moles obtained

Chemistry
0.4 moles of pcl3 and 0.3 moles of pcl3 added to access ofC2H5OH then maximum no of moles obtained

Chemistry
Na2CO3(aq)+ 2HNO3(aq)--> 2NaNO3+H2O(l)+CO2(g) how do I get net ionic?

Chemistry
Zn(s)+HCl(aq)--> ZnCl2(aq)+H2(g) net ionic??

Chemistry
How many moles of nitric oxide are formed from 0.60 mole of nitrogen dioxide

Chemistry
HCl(aq) + LiOH(aq)--> H2O(l) + LiCl(aq) Did I do this right? I need help on finding the net ionic equation

Chemistry
You have 2m^3 of a mineral ore sample. It has a mass of 1x10^4 kg. Calculate the density of the ore sample and express your results in g/cm^3 with appropriate scientific notation.

chemistry
Why do some reactions go to completion while others reach a state of equilibrium?

Chemistry
How many grams of ethanol must be added to 500.0 g of water to make a solution that freezes at 0.00 degrees fahrenheit? The molal freezing point depression constant for water is 1.86 degree celsius over moles.

Chemistry
5.58g of Fe reacted with 3.0g of oxygen. How many moles of Fe were used?

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
Balance the following redox reaction in basic solution. H2(g)+Fe3+(aq) ---> H2O(l)+Fe2+(aq)

Chemistry need asap
Situation: The Production of Nitric Acid can be achieved by the following process: Nitrogen monoxide gas(NO) + diatomic oxygen gas+ water (liquid) ===> Nitric Acid (aq) a. Show complete balanced reaction for process What I have: 4NO+ 3O2+ 2H2O > 4HNO3 b. The lab ...

Chemistry
When 26.16 g of iron is heated in the presence of excess chlorine gas, they will react to form 76.08 g of a compound called ntaining these 2 elements. If the molar mass of this compound is 644 g/mil find the molecular formula.

chemistry
proof that the energy of the first spectra line in Lyman series E =3/4Eo Eo=2.18×10-18

Chemistry (atoms)
How many atoms of oxygen, O, are in 0.0595 moles of water?

Chemistry
0.3975 g of an oxide of divalent metal on reduction with hydrogen gives 0.090 g of water. The atomic weight of metal is: a) 63.5 b) 24 c) 55.5 d) 40

Chemistry, que 10
How many atoms are present in one formula unit of calcium hydrogen carbonate Ca(HCO3)2? Could someone explain to me why the answer is 11? Thank you.

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

Chemistry
According to the quantum-mechanical model for the hydrogen atom, which of the following transitions would produce light with longer wavelength: 3p to 2s or 4p to 2s? A) The 3p to 2s transition would produce light with longer wavelength. B) The 4p to 2s transition would ...

Chemistry
What happens to an atom when it absorbs energy? 1) The atom stores the energy for later use. 2) The atom re-emits the energy as electromagnetic radiation. 3) The extra energy increases the speed of the electrons in their orbitals. 4) The extra energy increases the oscillation ...

Chemistry
Calculate the wavelength, in nanometers, of the spectral line produced when an electron in a hydrogen atom undergoes the transition from the energy level n = 2 to the level n = 1.

Chemistry
Find the frequency if given energy 6.3x10^-19 Do I use the formula E=hf? 6.3x10^-19=6.626x10^-34(f) Then do I divide E and H?

Chemistry
calculate the mass ratio of 25% cacl2 solution and water to prepare 500 g of a 5% salt solution

Chemistry
What pressur would the propane gas sample have at 75Ml

Chemistry
A chemist reacted 0.05 mol of sodium with water to form 50cm3 of sodium hydroxide what was the mass of sodium reacted Na+h2p-Noah+h2

Chemistry
A Solution Has A PH Of 3.4.What Is Its Hydrogen Ion Concentration?

Chemistry
The heat of combustion of C2H4 at 27 C at constant prssure is -333.3 Kcal. What will be the heat of combustion at constant volume considering the water to be in liquid state? (R=1.987 cal)

Chemistry
In a reversible reaction PCl5 ↔ PCl3 + Cl2, the value of K is 2.5. What will the partial pressure of Cl2 be?

chemistry
A Li2+ ion had its electron in an excited state. When the electron relaxed to the ground state (n = 1) a photon of light was emitted with an energy of 1.884×10−17 J. What energy level was the electron in before it transitioned to the ground state?

Chemistry
The principal quantum number (n): A) specifies the subshell of the orbital. B) specifies the principal shell of the orbital. C) specifies the 3-D shape of the orbital. D) specifies the maximum number of electrons. E) none of the above

Chemistry 2
The mechanism for the reaction of nitrogen dioxide with carbon monoxide to form nitric oxide and carbon dioxide is thought to be the following. NO2 + NO2 NO3 + NO Slow NO3 + CO NO2 + CO2 Fast What would be the overall balanced equation to this reaction?

Chemistry
The specific heat of a metal was found to be 0.38 J/g*°C. When 0.5007 g of this metal was heated in a stream of chlorine gas, it produced 1.0586 g of a metal chloride, MClx. a. Determine the formula of the metal chloride and the accurate atomic weight of the metal. b. What is...

Chemistry
The compound copper(II) nitrate is a strong electrolyte. Write the reaction when solid copper(II) nitrate is put into water:

chemistry
A 45-kg person drinks 390. g of milk, which has a "caloric" value of approximately 3.0 kJ/g. If only 17% of the energy in milk is converted to mechanical work, how high (in meters) can the person climb based on this energy intake? [Hint: The work done in ascending is given by ...

chemistry
A 77.40 kg piece of copper metal is heated from 19.6°C to 337.3°C. Calculate the heat absorbed (in kJ) by the metal.

chemistry
A sheet of gold weighing 11.4 g and at a temperature of 15.6°C is placed flat on a sheet of iron weighing 24.2 g and at a temperature of 54.9°C. What is the final temperature of the combined metals? Assume that no heat is lost to the surroundings. - (11.4)(0.129)(Tf – 15.6...

chemistry
A 0.1219-g sample of solid magnesium is burned in a bomb calorimeter that has a heat capacity of 1769 J/°C. The calorimeter contains exactly 271 g of water, and the temperature increases by 1.126°C. Calculate the heat given off by the burning Mg, in kJ/g and in kJ/mol.

CHEMISTRY
write the orbital notation for the following set of quantum numbers n=1, l=0, m=0

CHEMISTRY FOR ENGINEERS
What is the frequency and wave number associated with light of wavelength equal to 6000 angstrum

Chemistry
Prepare 0.03 mole fraction solution of NaOH in water Total volume of solution is 100ml

Chemistry
You add 7.326g of solid CaCl2 to 45.5 mL of water in a coffee cup calorimeter and measure as the temp. Increase from 22.6 C to 41.5 C. Specific heat water is 4.184 J/ g.C and the density of water is 0.9977 g/mL. Find the mass of water. PLEASE HELP ME!!!

Analytical chemistry
Calculate to four decimal places the mass of purely dry MgCO3(Magnesium Carbonate) required to make 1L of a 1000 ppm Mg stock solution.

chemistry
How we make 0.02ppm solution in 25ml?

Chemistry
i need help making an acrostic poem using the word nonmetal

chemistry need help
Balance the following equation in an acidic and basic medium * Cr^(+3)+BrO^(-)--->CrO4^(2-)+Br^(-)

CHEMISTRY
A lamp of marble chips was dropped in excess 0.1mol/dm hydrochloric acid and observed for sometime. (a) State what you would see. (b)Describe how the rate of reaction changed with time. (c)Explain why the reaction stopped after sometime. (d)The reaction was rather slow.State ...

chemistry
For the following reaction Co(g)+H2o(g)=Co2(g)+H2(g) If the initial concentrations of Co and H2o are 1.00 mol in a 50 L vessel, what is the number of mole of each species at equilibrium, if the equilibrium constant Kc= 0.85 at 1000 C? please can any one explain how to do this ?

Chemistry
I have a 0.6573g mixture of NaHCO3 and Na2CO3. Calculate the mass of NaHCO3 and Na2CO3 in the unknown mixture.Also calculate the mass of NaCl formed in the reaction of the mixture and HCl.

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