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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Calculate the pH values and draw the titration curve for the titration of 500 mL of 0.010 M acetic acid (pKa 4.76) with 0.010 MKOH. Calculate the pH of the solution after 490 mL of the titrant have been added.

Chemistry
Calculate the new freezing point and the new boiling point of an aqueous solution that contains 40.5 g of Calcium Nitrate dissolved in 225 grams of water.

chemistry
Word equation of dissolving zinc in dilute susurphuric acid

Chemistry
A typical solid fertiliser for use with household plants and shrubs contains the elements N, P and K in the ratio of 15g: 30g: 15g per 100g of fertiliser. The recommended usage of fertiliser is 14g of fertiliser per 5dm^3 of water. What is the concentration of nitrogen atoms ...

Chemistry
Describe the procedure you would follow to determine the concentration of vitamin c in a sample if the volume of dcpip required to reach the end point were more than the 10-mL graduated cylinder could hold. The titration must still be carried out in the 10-mL graduated ...

chemistry
Which of the following statements is false ? a) S is negative when water condenses at 100oC b) Ssurroundings is positive when water condenses at 100oC c) Suniverse is equal to zero when water condenses at 990C d) Suniverse increases when water condenses at 110oC

Chemistry
A closed bottle contains a solution of 5.0% by mass acetone [(CH3)2CO] in water. Calculate the vapour pressure (in kPa) of this solution at 25oC. The vapour pressure of pure water at 25oC is 3.17 kPa and that of pure acetone is 30.7 kPa.

Chemistry
Fireflies flash at a rate that depends on the temperature. At 29oC, the average rate is 3.3 flashes every 10 seconds, whereas at 23oC, the average falls to 2.7 flashes every 10 seconds. Calculate the "energy of activation" (in kJ/mol) for the flashing process.

Chemistry
What type of solid is Ne? Metallic? Molecular? Ionic? or Covalent Network?

Chemistry
What will be the mass of ferrous sulphide formed when 20 gram of pure sulphur reacts with iron ?

Chemistry
How many grams of H2O are needed if 41.85g of O2 are to be produced from the reaction below? 2K2O2 + 2H2O = 4KOH + O2

chemistry
A dilution is made during the preparation of a reaction mixture. The compounds are: 2.00 ml of 0.325 KMnO4, 7.50 ml of 0.155 M Oxalic acid, and 10.00 ml of H2O. What are the final concentrations of the compounds?

Chemistry
PartA: What volume of 10.0M NaOH is needed to prepare a buffer with a pH of 7.79 using 31.52 g of TrisHCl? TrisHCl is a weak base and the molecular weight is 157.67 g/mol. I found the solution, it is 6.67 milliliters. Part B: "The buffer from Part A is diluted to 1.00 L. To ...

Chemistry
Consider a one step reaction. Which of the following does not describe the activation energy of the process? The minimum amount of energy needed for a reaction to occur The energy difference between the starting point and the transition state The energy difference between the ...

enviromental chemistry
If 10 ppm of nitrogen dioxide is present 1000 L of air at a pressure of 1 atm and temperature of 27 °C, what is the amount of ammonia necessary to react?

Chemistry
The common picnic ant walks with a velocity of 0.01 meters per second (m/s). How long will it take an ant to walk across a 8 ft long picnic table, assuming it does not meet with an untimely demise along the way? (1 m = 39 in, 1 ft = 12 in) 8ft/1 X 12in/1in X 2.54cm/1in

Chemistry
The photoelectric work function of a metal is the minimum energy needed to eject an electron by irradiating the metal with light. For calcium, this work function equals 4.34 x 10-19 J. If light with a wavelength of 256 nm impinges on a piece of calcium, what is the speed of ...

Chemistry
The photoelectric work function of a metal is the minimum energy needed to eject an electron by irradiating the metal with light. For calcium, this work function equals 4.34 x 10-19 J. If light with a wavelength of 256 nm impinges on a piece of calcium, what is the speed of ...

chemistry
In part B of my question, I was asked calculate the number of atoms in 0.462 mol of 13C (mass number of this Carbon is 13). I received the correct answer of 2.78E23 atoms. However, I do not know how to do Part C of my question, which asks "Based on your answer in Part B, how ...

Chemistry
How many grams of urea would have to be dissolved in 250 grams of water to give it a freezing point of -4.degrees celcius

chemistry
Calculate the pH values and draw the titration curve for the titration of 500 mL of 0.010 M acetic acid (pKa 4.76) with 0.010 MKOH. Calculate the pH of the solution after 490 mL of the titrant have been added. Calculate the pH of the solution after 500 mL of the titrant have ...

Chemistry
Magnesium has three stable isotopes: 24Mg, 25Mg, 26Mg. The relative abundance of 24Mg is 79%. What are the relative abundances of 25Mg and 26Mg?

CHEMISTRY
1. Not sure of how to do the calculations... Make a 0.200 m solution of NaCl in a 100. mL volumetric flask. ... Solution A's question or statement is the same but with M (molarity) Is this right? The small m means molality. If it were changed to capital M, then solution A's ...

Chemistry
If 0.35 moles of SO3 is placed in a 1 dm3 flask and allowed to come to equilibrium at a high temperature, 0.207 mole of S03 remains. Calculate Kc For the reaction 2SO3 Double arrow 2SO2 +02

Chemistry
its takes 145 mL of zinc nitrate to react completely with 175 ml of 1.5 M potassium hydroxide. what is the concentration if zinc nitrate?

Chemistry
1. Not sure of how to do the calculations... Make a 0.200 m solution of NaCl in a 100. mL volumetric flask. ... Solution A's question or statement is the same but with M (molarity) Is this right? The small m means molality. If it were changed to capital M, then solution A's ...

chemistry
a student performs the lab on an unknown metal and obtain the following data

Chemistry
Net ionic equation for the reaction of strontium nitrate and sodium carbonate.

Chemistry
We did a lab about the heat hydration of sodium acetate with water. I got that the enthalpy of anhydrous sodium acetate is exothermic while the enthalpy of trihydrate sodium acetate is endothermic. Also that the enthalpy of the hydration of the sodium acetate salt is also ...

chemistry
How to balanced chemical equation and identify the type of reaction for solid ammonium nitrate decomposes into dinitrogen monoxide gas and water

Chemistry
How many grams of CaCl2 are needed to produce 10.0 grams of NaCl?

chemistry
You are making 40g of a 29% (w/w) sucrose solution. what amount of sucrose and water would be used. each in grams please

Chemistry
An aqueous solution of volume, v1 cm3, contains a mass, mg,of a compound to be extracted. When shaken with v2 cm3 of an organic solvent, a certain proportion, x, of this compound dissolves. Derives an expression for x in terms of v1, v2 and the partition coefficient, k.

chemistry
A patient is prescribed 0.210 mg of a drug that is available in 70 μg tablets. How many tablets are needed? (Remember that the number of significant figures does not matter because the number of tablets is being counted.)

Math, physics, chemistry
calculate total ionic strength of solution in which concentration of CuSO4 and Al2(SO4)3 is 0.1 molar

chemistry
In the reaction K2CrO4(aq) + PbCl2(aq) → 2KCl(aq) + PbCrO4(s), how many grams of PbCrO4 will precipitate out from the reaction between 500.0 milliliters of 3.0 M K2CrO4 in an excess of PbCl2?

Chemistry
Consider equation 3A+B=C+D. You react 4 moles of A with 2 moles of B. Which of the following is true? 1) Limiting reactant (L.R.) is one with higher molar mass 2) A is L.R. because you need 6 moles of A and have only 4 moles 3) B is L.R. because you have fewer moles of B than ...

Chemistry
How many mL of SCN^-1 and water to put in a 10 mL solution with 5 mL of Fe^3+ already in it?... We're finding those values to make standard solutions of 0.00 mM FeSCN^2+ 0.020 " 0.040 " 0.060 " 0.080 " 0.100 " I know that you have to use M1*V1=M2*V2,but I'm not sure where to ...

chemistry
Robin the Research scientist prepares 100 mLs of a solution of 100 mM of Tris HCl. What is the pH? and part two for this question Calculate the pH when the scientist adds 100 ul of 50% NaOH

Chem
2. Suppose a chemistry student made 2000. mL of 6.00 M HCl. He accidently spilled half of this solution on the floor. What is the Molarity of HCL left in the beaker? Explain the answer... - for this problem, would I use the eq'N, M1V1=M2V2. 3. What is the molarity of a sol'n ...

Chemistry
Robin the Research scientist prepares 100 mLs of a solution of 100 mM of Tris HCl. What is the pH? and part two for this question Calculate the pH when the scientist adds 100 ul of 50% NaOH I am confused since we do not know the conjugate base concentration so how to solve for...

chemistry
Calculate the pH values and draw the titration curve for the titration of 500 mL of 0.010 M acetic acid (pKa 4.76) with 0.010 MKOH. Calculate the pH of the solution after 490 mL of the titrant have been added. Calculate the pH of the solution after 500 mL of the titrant have ...

Chemistry
Robin the Research scientist prepares 100 mLs of a solution of 100 mM of Tris HCl. What is the pH? I am confused since we do not know the conjugate base concentration so how to solve for the pH

Chemistry
Calculate the number of liters of hydrogen gas at STP that could be produced by the reaction of 4.80g of magnesium with excess hydrochloric acid. Mg+HCl=MgCl2+H2

chemistry
How many mole of CL2 are needed to react with 2.0 mole Na?

Chemistry
What volume is occupied by 100 g of air at room temperature (d = 1.20 g/L)?

chemistry
How many mole of CL2 are needed to react with 2.0 mole Na?

Chemistry
cooking oil, a non-polar liquid, has a boiling point in excess of 200 degrees Celsius. Water boils at 100 degrees. how can you explain these facts, given the strength of water's hydrogen bonding?

chemistry
how can i make 30 ml, 0.227 mol of hydroiodic acid from 50 ml hydroiodic acid of 57 wt% in water?

chemistry
commercially available concentrated Hydrochloric acid is 37.0% w/w Hcl.its density is 1.18g/ml.using this information calculate (a)the molarity of concentrated Hcl,and (b)the mass and volume (in ml)of solution containing 0.315 mol of Hcl?

chemistry
How many grams of MgO are produced during an enthalpy change of -199 kJ? 2 Mg(s) + O2(g) → 2 MgO(s) ΔH = -1204 kJ

Chemistry
(1)Make 500 ML of 4N H3PO4. How many grams will be needed? (2) In a titration procedure, 20mL of 2N solution were required to titrate 5mL of an unknown solution. What is the normality of the solution? (3) How much of a 0.01M can be made from 20mL of 6M HCl? (4)How many grams ...

Chemistry
The human body “burns” glucose (C6H12O6) for energy. a. Write a balanced chemical reaction for the complete combustion of glucose to CO2(g) and H2O(l) such that the stoichiometric coefficient for glucose is 1. b. When 1.00 g of glucose are completely burned at 298.15 K and...

Chemistry
Calculate the Delta Hf of the OH- ion given that the Delta Hf (H2O) = -285.8 kJ mol-1.

Chemistry
How much heat (in kilojoules) is required to warm 11.0 g of ice, initially at -14.0 ∘C, to steam at 112 ∘C? The heat capacity of ice is 2.09 Jg−1∘C−1 and that of steam is 2.01 Jg−1∘C−1.

chemistry
Explain the first ionization energy of lithium is greater than that of sodium

chemistry
How many unpaired electrons for cr3+

chemistry
A solution of 25.0mL of 0.10mol/L hydroiodic acid is titrated with 0.10mol/L ammonia.Determine the pH at equivalence.

Chemistry 112
Can someone please explain to me how to calculate reaction order with respect to something? I've read this in my textbook, and I watched videos on YouTube, but I still don't understand. Please help.

Chemistry
How many liters would 1.000g of helium gas occupy at STP?

chemistry
Calculate ∆S universe for the process H2O (s) → H2O (l) given that ∆Hfusion = 6.02 kJ/mol and ∆S system = 22.1 J/K mol . Remember that ∆S surrounding = -∆Hsystem / T. a) -20oC b) 0oC c) 20oC

Chemistry 112
Can rate of law be a decimal??

organic chemistry
The constants for Antoine’s equation for TCE (based on log10 and o C) are: A= 6.5183, B = 1018.6 and C = 192.7. If a container (negligible volume) is placed in a sealed room 1000 m3 at 30 oC, how many grams of TCE will evaporate upon reaching equilibrium with the liquid and ...

chemistry
From each pair of substances below, choose the one with the higher molar So, at 298 K a) Hg (s), Hg (l) d) C2H6 (g), C2H4 (g) b) HI (g), HCl (g) e) H2 (1 atm), H2 (2 atm), 1 mol at 298 K c) NH3 (g), Ne (g) f) NaCl(s), NaCl (aq)

Chemistry
Compunds formed by NH4+ and NO3-

Chemistry
The vapor pressure of pure water at 30C is 31.8Torr. What is the vapor pressure of a solution of NaCl dissolved in water when the mole fraction of NaCl is 0.111? I am wondering if this would be correct. 0.11*31.8= 3.5 Torr Is there another way to solve this and get the same ...

chemistry
a pipet can be calibrated. we expected the volume to be 25.00ml, but the actual volume was significantly less. if you had measured the density of an unknown with this pipet and assumed that v=25.00ml, your result would not be correct. would it be too high or too low? Explain

Chemistry
Given Ka values of 5.76×10^-10 & 4.8×10^-10, for NH4+ anf HCN.what is the equilibrium constant for following reaction? NH4+ + CN- >< NH3 + HCN

chemistry
What is the half-life of an isotope that decays to 50% of its original activity in 55.6 hours?

Chemistry
Say there is a diluted solution and we need to find the final concentration of it, using the equation M1V1 = M2V2. Does this method change, if the compound (concentration that we're trying to find), is in a solution that has already reacted with another compound? Ex: CaCO3 + ...

Chemistry
In the aqueous solution of H2SO4 its mole fraction is 0.2 then closest value of molality or solution is a)13.9 b)9.8 c)10.2 d)11.2

Chemistry
What is the pH of a buffer solution of 0.125M Acetic acid and 0.250M Sodium acetate? the Pk of Acetic acid is 4.76

Chemistry
What substance will have the lowest surface tension? A) HOCH2CH2OH B) CH2F2 C) CH3CH2F D) CH3CH2OH E) CH3CH2CH CH3CH3

College Chemistry
If the reaction rate increases by 2.6 when the temperature increases from 20-30 degrees Celsius, what is Ea? Do we use 2.6 in place of (k2/k1) or multiply something by 2.6? Lost, please help.

chemistry
what mass in grams of hydrogen gas is produced using234g of nitric acid

Chemistry
How much energy is required to convert 360 gram of ice having temp -10 c to convert in to steam

Chemistry
The density of water at 60 degrees C is 0.98338 g/mL. What is the mass of 37.48 mL of water in a graduated cylinder (not including the mass of the graduated cylinder)

Chemistry
(Paper Chromatography) 1. What carrier solution might work well to separate newspaper inks? Why? 2. What carrier solution might work to separate different salts? Why? 3. What carrier solution might work to separate different fatty acids? Why? I really have no idea what the ...

Chemistry
1. An empty balloon weighs 10.0 g and is filled to a volume of 20.0 L with CO gas. If the density of air at 25.0 °C and 1.00 atm is 1.17 g/L, will the balloon float? 2. Determine the volume of gas produced at 20.0 °C and 1.00 atm from the complete combustion of 1.0 kg of ...

Chemistry
A container of gas at 53 psi is compressed to one third its original volume. What is the new pressure of the gas?

Chemistry II
How much heat (in kJ) is required to warm 10.0 g of ice, initially at -15.0 ∘C, to steam at 114.0 ∘C? The heat capacity of ice is 2.09 J/g⋅∘C and that of steam is 2.01 J/g⋅∘C.

Chemistry
How much heat (in kJ) is required to warm 10.0 g of ice, initially at -15.0 ∘C, to steam at 114.0 ∘C? The heat capacity of ice is 2.09 J/g⋅∘C and that of steam is 2.01 J/g⋅∘C.

Chemistry
Calculate the number of moles of 2.8 of nitrogen (iv) oxide.

Chemistry
This is a conversion question. 2.78mg to ___________ kg. I've tried the standard formula - ex (2.5 m) (1000m/1m)=2500mm - but it just gives me 2.78e-6. Please help it's driving me crazy.

Chemistry
Compound K is a hydrocarbon. Combustion of 6.51 g of K gave 20.47 g of carbon dioxide and 8.36 g of water. The relative molecular mass of K was found to be 84. Calculate the empirical and molecular formula of K

Chemistry
Assuming I have the following reaction: LiO2 + C +2 Mg -> LiC + 2MgO I'll be using 0.1 g of LiO2 to react with 1.2 mol C and 2.2 mol Mg in excess. How much C and Mg in grams do I need?

chemistry
Express the composition of each of the following compounds as the mass percents of its elements...? 59) Express the composition of each of the following compounds as the mass percents of its elements. a) formaldehyde, CH2O b) glucose, C6H12O6 c) acetic acid, HC2H3O2

Chemistry
In a discussion,a study argued that calcium ions when asded to toothpaste would enhance the performance of the toothpaste by further strengthening teeth. Therefore, he suggested the addition of calcium hydrogen carbonate, calculate the solubility of calcium fluoride in a ...

chemistry
1 g of a mixture of nahco3 annd na2co3 was heated at 300 deg celsius.the volume of co2 obtained at stp are found to be 112ml.calculate the % of na2co3 in the mixture. please help i am not able to understand!!

Chemistry
How much energy (in kilojoules) is released when 29.0 g of ethanol vapor at 88.0 ∘C is cooled to -10.0 ∘C? Express your answer to two significant figures. q = ______________ kJ Ethanol has mp = -114.5 ∘C, bp = 78.4 ∘C, ΔHvap = 38.56 kJ/mol and ΔHfusion = 4.60 kJ/mol...

Chemistry
Explain why olive oil has a higher viscosity than water, by selecting an appropriate word from the provided list and filling in the following blanks. Oleic acid has a higher viscosity than water because it is a much________ molecule than water with ________ ________. List of ...

Chemistry
Rxn 1:     4 NH3(g) + 5 O2(g) ⇌ 4 NO(g) + 6 H2O(g)         If the equilibrium constant, Kc, for Rxn 1 is 0.0015, determine the equilibrium constant, Kc, for the    reaction:   2 NH3(g) + 5/2 O2(g) ⇌ 2 NO(g) + 3 H2O(g) I'm not sure how to start this problem ...

Chemistry
How much does 1.0 ft^3 of mercury weigh given the density of mercury is 13.6 g/ml?

chemistry
an over the counter pain reliever melts at 78degree celcius. convert this temperature to f and k

chemistry
how many fluid ounces are contained in 1qt of milk. 2.how many cups are contained in 1l of soda

chemistry
why should a new boiling Chip be added to a liquid that has already been heated with a boiling Chip

chemistry
1) A Galvanic cell runs on the following reaction: Co (s) + Cu2+ (aq) → Co2+ (aq) + Cu (s) Draw a diagram for this Galvanic cell, labeling the electron flow, the anode and cathode, and the positive and negative sides of the Galvanic cell. 2) A Galvanic cell runs on the ...

chemistry
a woman was told to take a dose of 1.20g of calcium daily ,how many 200mg tablets should she take^

Chemistry 112
Calculate the MnO4- concentration of the diluted sample when the sample is prepared in the following manner: Add 2 drops oxalic acid, 4 drops permanganate and 8 drops water. The original permanganate is 0.25M. I don't understand how to do this, any help would be appreciated.

Some basic concept of chemistry
0.5M aluminum sulphate aques solution normality calculation

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