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August 21, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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Chemistry
8 g of sulphur is burnt to form SO2 which is oxidized by Cl2 water The solution is treated with BaCl2 solution The amount of BaSO4 precipitated is A/ I mole B/ 0.5 mole C/ 0.24 mole D/. 0.25 mole Which option is correct??
Tuesday, June 24, 2014 at 3:13am

Chemistry
The decompostion of dinitrogen pentoxide has been studied in carbon tetrachloride (CCl4) at a certain temperature: 2N2O5→4NO2+O2 [N2O5] Inital rate (M/s) 0.92 ...... 0.95x10^-5 1.23 ...... 1.20x10^-5 1.79 ...... 1.93x10^-5 2.00 ...... 2.10x10^-5 2.21 ...... 2.26x10^-5 ...
Tuesday, June 24, 2014 at 2:47am

chemistry
a student weighs out 37.0 grams worth of an unknown liquid into her graduated cylinder while preparing an experiment. Her formerly empty 100 mL graduated cylinder now contains exactly 25mL of liquid. She then adds 3.25 ml of H2O and according to her instructions the graduated ...
Tuesday, June 24, 2014 at 12:28am

chemistry
Microwave ovens emit radiation with an energy of 2.05x10^-24 J for every photon released. What is the wavelength in nm for tis energy?
Tuesday, June 24, 2014 at 12:12am

chemistry
What volume of a 0.610 M NH4I solution is required to react with 525 mL of a 0.300 M Pb(NO3)2 solution?
Monday, June 23, 2014 at 11:06pm

Chemistry
A balloon contains 0.350 mol of Ar at 5.00°C and 68.0 kPa pressure. What is the volume of the gas?
Monday, June 23, 2014 at 9:27pm

chemistry
When 40.0 mL of 1.00 M H2SO4 is added to 80.0 mL of 1.00 M NaOH at 20.00°C in a coffee cup calorimeter, the temperature of the aqueous solution increases to 29.20°C. If the mass of the solution is 120.0 g and the specific heat of the calorimeter and solution is 4.184 J...
Monday, June 23, 2014 at 10:59am

chemistry
Which one of these is NOT a mechanism of heat transfer Select one: a. Reflection b. Radiation c. Convection d. Conduction
Sunday, June 22, 2014 at 11:01pm

chemistry
Which one of the following statements regarding ideal gas laws is FALSE? Select one: a. An ideal gas has an infinite heat capacity b. The macroscopic ideal gas equation is PV = nRT c. The temperature must always be measured in Kelvin (K) d. A single molecule of gas has kinetic...
Sunday, June 22, 2014 at 10:59pm

Chemistry
10. For the titration of 20.00 mL 0.1000 M lactic acid with 0.1000 M NaOH, calculate the pH: a. before any titrant is added b. 10.00 mL prior to the equivalent point c. at the equivalent point d. 10.00 mL after the equivalence point. Plot the points obtained on a graph of pH ...
Sunday, June 22, 2014 at 10:54pm

Chemistry
A 5.00 mL aliquot of vinegar (acetic acid, FW = 63 g/mol) was diluted and titrated with 0.1104 M NaOH requiring 32.88 mL. If the vinegar has a density of 1.055 g/mL, calculate its acidity as % acetic acid
Sunday, June 22, 2014 at 10:48pm

Chemistry
I have an exam in a day and I'm confused on how to solve this question. Do I use PV=nRT? Do I find out the molecular formula of the gas from the percentage of nitrogen and oxygen? A sample of a mixture of gases contains 80.0% nitrogen gas and 20.0% oxygen gas by volume. ...
Sunday, June 22, 2014 at 9:03pm

chemistry
Calculate the atomic mass of naturally occurring molybdenum (Mo) which contains the following isotopes. Isotope Abundance (%) Atomic mass (a.u.) 92Mo 15.8 91.91 94Mo 9.0 93.90 95Mo 15.7 94.91 96Mo 16.5 95.91 97Mo 9.5 96.91 98Mo 23.5 97.91 100Mo 9.7 99.91
Sunday, June 22, 2014 at 6:20pm

chemistry
Draw “arrows in a box” diagrams to illustrate the ground-state electronic configuration of the following species: 12 6C , 32 2 16 S − 28 14 Si , 57 2 28 Ni + , 35.5 17Cl− , 40 2 20Ca + , 31 15P
Sunday, June 22, 2014 at 6:20pm

chemistry
Indicate which of the following quantum states are allowed and which are disallowed under the rules governing the electronic structure of atoms. n = 2, l = 1, ml = 0, ms = ½ n = 3, l = 3, ml = -2, ms = -½ n = 4, l = 3, ml = -2, ms = ½ n = 3, l = 2, ml = 2...
Sunday, June 22, 2014 at 6:19pm

chemistry
Sulphuric acid (H2SO4) solution reacts with magnesium metal (Mg) to magnesium sulphate and hydrogen according to: H2SO4 + Mg → MgSO4 + H2 How many litres of 5.00 M sulphuric acid would be required to dissolve 20.00 g of magnesium and how many mol of hydrogen would be ...
Sunday, June 22, 2014 at 6:16pm

chemistry
29.8 ml of ethanol (density = 0.789 g/ ml) initially at 9.9 degree celsius is mixed with 33.8 mL of water (density = 1.0 g/mL) initially at 27.8 degree celcius in an insulated beaker. Assuming that no heat is lost, what is the final temperature of mixture? How do I start this ...
Sunday, June 22, 2014 at 1:58pm

chemistry who step by step for me
1.2g mixture of na2c03 and k2c03 was dissolved in water to form 100cm3 of solution, 20 cm3 of this solution required 40cm3 of 0.1 hcl for neutralization. Calculate the weight na2c03 and k2c03 in the mixture? My calculation 20cm3/100cm3 = 0.2 x/53 + (0.2g-X) + y/69 = 0.004 0....
Sunday, June 22, 2014 at 1:52pm

chemistry step by step for me
0.6g mixture of licl and bal was treated with 40ml of 0.2N agn03 and the excess ag on titration required 25ml of 0.1N kcns for the end point using ferric alum as the indicator. What is the percentage of iodine in the mixture Who helps me step by step for me clearly
Sunday, June 22, 2014 at 1:01pm

Chemistry
The equation for the reaction of sucrose(sugar)with oxygen is C12H22O11+12O2--->12CO2+11H2O how many g of co2 is produced per g of sucrose used?how many mol of oxygen gas is needed to react with 1.0g sucrose?(C12H22O11=342g/mol)
Sunday, June 22, 2014 at 9:19am

chemistry
Can anyone explain to me the rate of disappearance and appearance? I had two problems and ive figured them out but i dont understand why they were solved this way. If the rate of appearance of Cr(SO4)3 is 1.24mol/min then what is the disappearance of C2H6O? 2 K2Cr207 + 8 H2SO4...
Saturday, June 21, 2014 at 10:58pm

chemistry
how much kg of co2 will be present in 1 ml of co2 sqample?
Saturday, June 21, 2014 at 9:47pm

Chemistry pls clearly step step for me
2gm of mixture hydrated sodium carbonate and sodium bicarbonate was dissolved in water and made up to 250cc. 25cc of this solution was titrated using methyl orange as indicator and 22.5cc of 0.087N hcl were required for naturalization. calculate the percentage of sodium ...
Saturday, June 21, 2014 at 9:08pm

chemistry Please who helps me stpe by step
2gm of mixture hydrated sodium carbonate na2c03 /OH20 and sodium bicarbonate was dissolved in water and made up to 250cc. 25cc of this solution was titrated, using methyl orange as indicator and 22.5cc of 0.087N hcl were required for neutralization. Calculate the percentage of...
Saturday, June 21, 2014 at 1:59pm

chemistry
What is the magnitude change in pH when 1.8g of NaOH is added 1L of a solution that is 0.100M in NH3 and 0.100 in NH4Cl? Kb for NH3 1.8 * 10^-5
Saturday, June 21, 2014 at 12:39pm

Chemistry
To prepare 100g of 19.7% by weight solution of NaOH.how many grams each of NaOH and H2O are needed?
Saturday, June 21, 2014 at 12:08pm

CHEMISTRY
Calculate the maximum work done when two moles of N2 expands isothermally from 10 litres to 20 litres at 25o C
Saturday, June 21, 2014 at 8:12am

Chemistry
A solution buffered at a pH of 5.00 is needed in an experiment. Can we use acetic acid and sodium acetate to make it? If so, how many moles of NaC2H3O2 must be added to a 1.0L of a solution that contains 1.0 mol HC2H3O2 to prepare the buffer. The Ka of acetic acid is 1.8x10^-5...
Friday, June 20, 2014 at 12:45pm

Chemistry 10As
How will you prepare 500ml of 16%equeous ethanol(46.1g/mol)
Friday, June 20, 2014 at 10:04am

chemistry
Appliances based on the concept of vaporization and latent heat of vaporization with explanation.
Friday, June 20, 2014 at 9:03am

Chemistry
biochemists consider the citric acid cycle to be the central reaction sequence in metabolism. One of the key steps is an oxidation catalyzed by the enzyme isocitrate dehydrogenase and the oxidizing agent NAD+. Under certain conditions, the reaction in yeast obeys 11th-order ...
Thursday, June 19, 2014 at 10:53pm

Chemistry
Yesterday we combined Hydrochloric Acid HCl with Sodium Hydroxide NaOH in a violent reaction that resulted in water H2O and common table salt NaCl. How many grams of hydrochloric acid should we use so we have exactly enough to react with 40g of sodium hydroxide? You'll ...
Thursday, June 19, 2014 at 10:11pm

chemistry
what would the written chemical reaction be to this problem? How many grams of hydrochloric acid should we use so we have exactly enough to react with 40g of sodium hydroxide? You'll need to write a chemical reaction, balance it, and then perform your calculation.
Thursday, June 19, 2014 at 10:02pm

Chemistry
How many grams of hydrochloric acid should we use so we have exactly enough to react with 40g of sodium hydroxide? You'll need to write a chemical reaction, balance it, and then perform your calculation.
Thursday, June 19, 2014 at 8:11pm

Chemistry
A solution of KCI is saturated at 50 degrees C. How many grams of solute are dissolved in 100g of water?
Thursday, June 19, 2014 at 3:48pm

Chemistry
In the following reaction, 28 grams of Calcium Oxide CaO reacts with Carbon Dioxide CO2 to produce Calcium Carbonate CaCO3. How much Calcium Carbonate is produced? CaO+CO2 ---> CaCO3
Thursday, June 19, 2014 at 3:19pm

chemistry
Equilibrium is established in a reversible reaction when: A)the [product] = [reactants] B)rate of reaction of products = rate of reaction of reactants C)all the reactants dissolve or dissociate D)products are no longer produced
Thursday, June 19, 2014 at 2:19pm

Chemistry
Which base is the strongest for the given [H+]? A)10^-9 B)10^-11 C)10^-10 D)10^-12
Thursday, June 19, 2014 at 2:14pm

chemistry
A solution contains 72.0 g of HCl and 468 g of (C6H6). What is the mole fraction of benzene?
Thursday, June 19, 2014 at 1:10pm

chemistry
What is the percent yield of NaCl if 31.0 g of CuCl2 reacts with excess NaNO3 to produce 21.2 g of NaCl
Thursday, June 19, 2014 at 9:14am

chemistry
calculate the moles of solute present in 1.25 centimeter cube of 0.5 M h3po4 solution
Thursday, June 19, 2014 at 3:44am

chemistry
Why is respiration an exothermic reaction?
Wednesday, June 18, 2014 at 2:54pm

Chemistry
What type of reaction is photosynthesis, the process where carbon dioxide combines with water to form glucose in the presence of sunlight?
Wednesday, June 18, 2014 at 2:50pm

Chemistry
If a latex balloon had a volume of 7.00 L at 39 °C, what would be the volume of this balloon at 21 °C?
Wednesday, June 18, 2014 at 2:50pm

Chemistry
From the following data at 25°C, H2(g) + Cl2(g) → 2HCl(g) ΔH0 = −185 kJ 2H2(g) + O2(g) → 2H2O(g) ΔH0 = −483.7 kJ Calculate ΔH0 at 25°C for the reaction below. 4HCl(g) + O2(g) → 2Cl2(g) + 2H2O(g)
Wednesday, June 18, 2014 at 2:47pm

chemistry
In an experiment, Ann mixes concentrated sulfuric acid with water in a reaction test tube. The walls of the test tube turn hot. What type of reaction has occurred?
Wednesday, June 18, 2014 at 2:47pm

Chemistry
Determine the concentration of CO32- ions in a 0.18 M H2CO3 solution. Carbonic acid is a diprotic acid whose Ka1 = 4.3 × 10-7 and Ka2 = 5.6 × 10-11.
Wednesday, June 18, 2014 at 1:50pm

chemistry
what is the molarity of a solution prepared by dissolving 1.25g of hcl in water to make 30 centimeter cube of solution
Wednesday, June 18, 2014 at 1:37pm

chemistry
Using 32.00 g/mole as the molecular mass of oxygen and 28.01 g/mole as the molecular mass of carbon monoxide, solve the above problem. A)79.97 B)61.3 C)61.27 D)80.00
Wednesday, June 18, 2014 at 1:21pm

Chemistry
What is the mass of a proton? Is it 1g, 1amu, or something else?
Wednesday, June 18, 2014 at 12:36pm

Chemistry
If 4.168 kJ of heat is added to a calorimeter containing 75.40 g of water, the temperature of the water and the calorimeter increases from 24.58°C to 35.82°C. Calculate the heat capacity of the calorimeter (in J/°C). The specific heat of water is 4.184
Wednesday, June 18, 2014 at 12:31pm

chemistry
A gas occupies 210 mL at -73°C. To have the same gas occupy 360 mL: Should the temperature be increased or decreased? What is the new temperature? A)120 K B)0.0029 K C)340 K
Wednesday, June 18, 2014 at 11:48am

physical chemistry
1 mole of element x has mass, 0.444 times the mass of 1mole of element Y. one average atom of element x has mass 2.96 times the mass of one atom of ^12c. what is the atomic wt. of Y?
Wednesday, June 18, 2014 at 7:13am

chemistry
) Calculate the amount of unreacted aqueous ethanoic acid (CH3COOH(aq)) in the sample taken for titration with aqueous potassium hydroxide(KOH(aq)). Clearly show the steps in your calculation. (1 mark) (v) Hence calculate the amount of aqueous ethanoic acid CH3COOH(aq)) in the...
Wednesday, June 18, 2014 at 7:12am

physical chemistry
the no. of atoms in 558.5g of Fe (at wt = 55.85u) is:
Wednesday, June 18, 2014 at 7:09am

physical chemistry
the atomic wt. of two elements A and B are 40 u and 80 u respectively. if x g of A contains y atoms, how many atoms are present in 2x g of B?
Wednesday, June 18, 2014 at 7:08am

physical chemistry
the isotopic abundance of C-12 and c-14 is 98% and 2% by mass respectively. what would be the no. of atoms of c-14 isotope in 12g carbon sample?
Wednesday, June 18, 2014 at 7:05am

physical chemistry
1g of hydrogen contains 6x10^23 atoms. the atomic wt. of helium is 4 u. it follows that the number of atoms in 1g of He is:
Wednesday, June 18, 2014 at 7:01am

physical chemistry
if the atomic mass of sodium is 23u the no. of moles in 46g of sodium is:
Wednesday, June 18, 2014 at 6:59am

physical chemistry
a sample of ammonium phosphate (NH4)3PO4 contains 3.18 mole of H atoms. number of mole of o atoms in the sample is:
Wednesday, June 18, 2014 at 6:58am

physical chemistry
the atmospheric pressure on mars is 0.61 kPa. what is the pressure in mm of Hg?
Wednesday, June 18, 2014 at 6:56am

physical chemistry
which one of the following pairs of gases contains the same no. of molecules:
Wednesday, June 18, 2014 at 6:52am

physical chemistry
the approximate no. of molecules of co2 present in 44g of co2 is:
Wednesday, June 18, 2014 at 6:50am

physical chemistry
indium(atomic wt.= 114.82 u ) has two naturally occuring isotopes, the predominant one from has isotopic wt. 114.9041 and abundance of 95.72%. which of the following isotopic wt. is the most likely for the other isotope?
Wednesday, June 18, 2014 at 6:46am

physical chemistry
on chemical scale, the relative mass of the isotopic mixture of x atoms (x^20,x^21,x^22) is approximately equal to:(x^20 has 99 percent abundance)
Wednesday, June 18, 2014 at 6:43am

chemistry
The activation energy, Ea, for a zeroth-order reaction, X-->products, is most readily obtained from the slope of a plot of: (choose from below) -[X] vs time -ln k vs time -rate vs time -[X]^2 vs time -ln[X] vs time -1/[X] vs time -ln k vs 1/T, where T is temperature in -ln ...
Wednesday, June 18, 2014 at 12:54am

chemistry
A reaction has a first order rate constant of (6.25x10^-5 1/s) at T=298.15K and (0.0000538 1/s) at T=338.15K. What is the value of the rate constant at T=316.15K?
Wednesday, June 18, 2014 at 12:50am

chemistry
According to the mechanism below, what is the correct expression for the rate consumption of A? In the mechanism, M is a molecule that collides with A and A* is a highly-energized for of A. Step 1: A+M <--> A*+M : rate constants k1 and k-1 Step 2: A* <--> C : rate ...
Wednesday, June 18, 2014 at 12:48am

chemistry
The decomposition reaction, x-->products, is second-order with rate constant k=0.0183 L/(s)(mol). How long will it take for the decomposition to be 95% complete, if the intitial concentration of X is 1.25mol/L? Thanks
Wednesday, June 18, 2014 at 12:44am

organic chemistry
1. Arrange the following in order of decreasing reactivity toward nitration. Fully explain please I could use some help!! A. acentanilide, b. bromobenzene, C. acetophenone, D. toluene 2. Explain why p-nitrophenol is a stronger acid than phenol itself? Would p-methoxyphenol be ...
Tuesday, June 17, 2014 at 10:32pm

Chemistry
1. Nitric acid is produced via the following equation: 3 NO2 + H2O = 2HNO3 + NO. How many grams of NO2 are required to produce 7.5 grams of HNO3?
Tuesday, June 17, 2014 at 10:00pm

Chemistry - Electroplating - URGENT
"To save on production costs, most automobile bumpers are never coated with more than 200 g of chromium. Determine how much time a standard bumper should be immersed in a chromium vat." This is what I have so far- 96,485 coulombs are required to plate 1 Cr; 52/6 = 8....
Tuesday, June 17, 2014 at 8:40pm

chemistry
"To save on production costs, most automobile bumpers are never coated with more than 200 g of chromium. Determine how much time a standard bumper should be immersed in a chromium vat." This is what I have so far- 96,485 coulombs are required to plate 1 Cr; 52/6 = 8....
Tuesday, June 17, 2014 at 8:38pm

CHemistry
What is the concentration of Sulfate ion in a 0.5 M solution of Al2(SO4)3?
Tuesday, June 17, 2014 at 6:59pm

Organic Chemistry
These questions are somewhat difficult. I believe I am on the right track, but I want to make sure. 1. List these compounds in order of decreasing reactivity towards nitration. Explain your answer. a) acetanilide b) bromobenzene c) toluene d) acetophenone 2. a) Which is the ...
Tuesday, June 17, 2014 at 6:10pm

chemistry
find (i) the total no. of neutrons and (ii) the total mass of neutrons in 7mg o^14C. (assume that the mass of a neutron = mass of a hydrogen atom)
Tuesday, June 17, 2014 at 6:32am

chemistry
the weight of one atom of uranium is 238 amu. its actual wt. is ......g
Tuesday, June 17, 2014 at 6:30am

chemistry
how much time(in years) would it take to distribute one avogadro number of wheat grains if 10^10 grains are distributed each second?
Tuesday, June 17, 2014 at 6:28am

chemistry
the density of liquid mercury is 13.6 g/cm^3. how many moles of mercury are there in 1 litre of the metal?
Tuesday, June 17, 2014 at 6:26am

chemistry
average atomic mass of magnesium is 24.31 amu. this magnesium is composed of 79 mole % of ^24 Mg and remaining 21mole % of ^25 Mg. calculate mole % of ^26Mg.
Tuesday, June 17, 2014 at 6:25am

chemistry
calculate the number of malecules in a drop of water weighting 0.09 g
Tuesday, June 17, 2014 at 6:23am

chemistry
calculate the no. of molecules in 16g of methane is:
Tuesday, June 17, 2014 at 6:20am

chemistry
a sample of ethane has the same mass as 10million mulecules of methane. how many moles of CO2 are left?
Tuesday, June 17, 2014 at 6:19am

chemistry
the no. of neutrons in 5g of D2O(Dis 2/1 H) are:
Tuesday, June 17, 2014 at 6:14am

chemistry
calculate the wt. of 6.022x 10^23 formula units of CaCO3
Tuesday, June 17, 2014 at 6:12am

chemistry
from 200 mg of CO2, 10^21 molecules are removed. how many moles of CO2 are left?
Tuesday, June 17, 2014 at 6:09am

chemistry
if from 10 moles NH3 and 5moles of H2SO4 all hte H-atoms are removed in order to from H2 gas, then find the no. of H2 molecules formed.
Tuesday, June 17, 2014 at 6:06am

chemistry
if from 3moles MgSO4.7H2O all the 'o' atoms are taken out and converted into ozone, find the number of O3 molecules formed.
Tuesday, June 17, 2014 at 6:04am

chemistry
if the components of air are N2-78% ;O2-21%; Ar-0.9% and Co2-0.1% by volume (or mole) what would be the molecular weight of air?
Tuesday, June 17, 2014 at 6:01am

Chemistry
if 50 ml of a solution of ph 3 is mixed with 50 ml of a solution of 5, explain why the resulting ph is still about 3 and not 4?
Tuesday, June 17, 2014 at 5:01am

chemistry
Calculate the volume of nitrogen gas that will be produced in the air bag of a car when 88,8g of sodium azide is thermally decomposed at 22 C to give the bag a pressure of 1,10 atm
Tuesday, June 17, 2014 at 12:08am

Science (Chemistry)
4. A Beer’s Law plot was prepared for the reaction A(aq) + B(aq) AB(aq), plotting absorption over AB(aq) concentration. The linear equation for this plot was y = 78.3x. A solution was prepared by mixing 10.0mL of 0.100M A with 5.00mL of 0.100M B and adding enough ...
Monday, June 16, 2014 at 7:58pm

Chemistry
Determine the mass of carbon dioxide that will be formed when 131.0 g of propane (C3H8) is reacted with 32 g of oxygen (O2) C3H8 + 5O2 --> 3CO2 + 4H2O I got O2 as my limiting reagent. Then I used the mol of that which is 1 mol to find the mol of CO2 which I got as 0.6 mol. ...
Monday, June 16, 2014 at 7:31pm

CHEMISTRY
COPPER
Monday, June 16, 2014 at 1:50pm

Chemistry
Ramesh took two beakers A and B containing hot water and cold water respectively . In each beaker he dropped a crystal of copper sulphate . He kept it undisturbed. After some time what did he observe ? Why ?
Monday, June 16, 2014 at 1:42pm

chemistry
If i have 12 grams of potassium chlorate dissolved in 100g of water at 65 celsius how much would i need to make the solution saturated
Monday, June 16, 2014 at 11:38am

chemistry
Cobalt(2) chloride is commonly obtained from chemical supply houses as a hydrate with the formula COCL2*6H2O an analysis showed that 25.0 g of this hydrate contains 11.3 g of water what is the percent water by weight in this hydrate?'
Monday, June 16, 2014 at 8:31am

Chemistry
What volume of 0.109 M nitric acid is required to neutralise 2.50g barium hydroxide?
Monday, June 16, 2014 at 3:49am

chemistry
What is the chemical formula of ketohexose?
Sunday, June 15, 2014 at 8:21pm

analytical chemistry
Determine the concentration of iron in an aqueous solution containing 0.2810 grams of Fe(NH4)2(SO4)2 per liter of solution. Express the concentration in mg/dl.
Sunday, June 15, 2014 at 6:54pm

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