Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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.

Chemistry
A 75.0g sample of liquid contains 17.5% by mass of H3PO4 (molar mass = 98.0g/mol). If 215.0mL of Ba(OH)2 is needed to completely neutralize the acid, determine the concentration of the Ba(OH)2 solution used

Chemistry
Determine the mass of urea, CH2N2O, required to make 250mL of a 0.235 M solution

Analytical chemistry
Calculate to four decimal places the mass of pure dry CaCO3 required to make 1 L of a 1000 ppm Ca stock solution.

Chemistry
Heat from burning a fuel is absorbed by a copper calorimeter. The calorimeter has a mass of 81.34 g and contains 200.0 g of water initially at 21 degrees Celsius. a) How much heat was absorbed by the calorimeter and the water if the final temperature of the water is 36.40 ...

Chemistry
How much heat is required to melt 110g of ice at-45°C?

Chemistry
What is the maximum mass, in grams, of NH3 that can be produced by the reaction of 1.0 g of N2 and 1.0 g of H2 using the reaction below? N2+H2→NH3 (not balanced) A) 0.60 g B) 5.7 g C) 1.2 g D) 2.9 g

Chemistry
The number of moles of cl2 produce will be ??????? If one mole of pcl5 is heated at 250 in a vessel having a capacity of 10dm³.

Chemistry
Magnesium oxide can be made by heating magnesium metal in the presence of oxygen. The balanced equation for the reaction is: 2Mg(s)+O2(g)→2MgO(s) When 10.1 g of Mg are allowed to react with 10.5 g of O2, 14.5 g of MgO are collected. a) Determine the limiting reactant for...

Chemistry
What is the maximum mass, in grams, of NH3 that can be produced by the reaction of 1.0 g of N2 and 1.0 g of H2 using the reaction below? N2+H2→NH3 (not balanced) What is the maximum mass, in grams, of that can be produced by the reaction of 1.0 g of and 1.0 g of using ...

chemistry
If 20 grams of zinc reacts with hydrochloric acid, how much zinc chloride is produced?

Chemistry
Assuming 100% dissociation, calculate the freezing point and boiling point of 2.45 m Na2SO4(aq). Constants may be found here sites. google. com/site/chempendix/colligative.

chemistry
A 2.41 g lead weight, initially at 10.7 ∘C, is submerged in 8.08 g of water at 51.9 ∘C in an insulated container. Question: What is the final temperature of both the weight and the water at thermal equilibrium? Express the temperature in Celsius to three ...

chemistry
A volume of 115 mL of H2O is initially at room temperature (22.00 ∘C). A chilled steel rod at 2.00 ∘C is placed in the water. If the final temperature of the system is 21.40 ∘C , what is the mass of the steel bar? Use the following values: specific heat of ...

chemistry
increasing order of boiling points of NO2, KCl and N2

Chemistry
A sample of gas occupies 100ml at 25 degree celsius. What volume would the gas occupy at 32 degree celsius if the pressure remains constant

chemistry
what is the reaction between potassium chloride and bromine?

Chemistry
In the laboratory you will be provided with a 1.0 x 10-5 M primary stock solution of fluorescein (MW=332.31g/mol). The calibration curve should include a blank, 0.025, 0.05, 0.075, 0.10, 0.15, and 0.25 micromolar fluorescein solutions. Since you will be using 25 mL volumetric ...

chemistry
Calculate the number of CO2 molecules in 7.30×10−2 mole of CO2. Express your answer using three significant figures.

chemistry
Calculate the number of Li atoms in 3.0 moles of Li. Express your answer using two significant figures.

chemistry
0.350 L of 0.470 M H2SO4 is mixed with 0.300 L of 0.250 M KOH. What concentration of sulfuric acid remains after neutralization?

Chemistry
You are handed a well insulated container holding about 100ml of water at a temp between 75 deg C and 100 deg C. you are given a thermometer with a maxmimum temp of 50 deg C. create an experiment to determine the temp of the water. i am really confused on how to start this ...

Chemistry
In the laboratory you will be provided with a 1.0 x 10-5 M primary stock solution of fluorescein (MW=332.31g/mol). The calibration curve should include a blank, 0.025, 0.05, 0.075, 0.10, 0.15, and 0.25 micromolar fluorescein solutions. Since you will be using 25 mL volumetric ...

Chemistry
When 13.0 grams of acetylene, C2H2, is reacted, what mass of water, H2O, is produced?

chemistry
what is the skeleton chemical equation of this? And Balanced equation. Copper (ii) chloride + Lithium --> Lithium Chloride + Copper

chemistry
what is the skeleton chemical equation of this? And Balanced equation. Copper (ii) chloride + Lithium --> Lithium Chloride + Copper

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Homework Help: Science