chemsitry

95 results

chemsitry

how do you find PH of {H+} = 1.0 * 10 to the -5 power M?

chemsitry

what is the frequency of a wavelength of 764 nm?

Chemsitry

How do we improve the efficiency of Column Chromatography?

chemsitry

calculate Delta H of RXN 2 N2 (g) + 3 H2( g) ->2 NH3 (g)

chemsitry

buffer calculate the ph of the .1m propanoic acid Ka 1.35e-5

chemsitry

the ph of a .030M C2H5 COOH solution is 3.20. What is this acids Ka?

chemsitry

How many moles of \rm CaC_2O_4 are present in this kidney stone?

Chemsitry

Calculate the weight of KHP that will react with 25mL of .1M NaOH

Chemsitry

What is the name of the following ion compund. SrO Cr1I2

chemsitry

hydrogen burns in oxygen to for water.caculate the volume?

chemsitry

The weak acid HQ has pKa of 4.89. Calculate the [H3O+] of .035 M HQ. Thanks.

chemsitry

you start with 150.0g of pentane and 500.0L of O2. how many grams of H2O will you make?

chemsitry

calculate the work done when 50.0 g of tin dissolves in excess acid at 1.00 atm and 25c

chemsitry help again please

Write the formula of the conjugate base for acid HClO2 .

Chemsitry

How many milliliters of 0.200M NaOHsolution are needed to react with 44.0 mL of a 0.300 M NiCl2 solution?

organis chemsitry

what is the main structural feature of the azo dyes that causes them to be colored compounds.

Grade 9 chemsitry

Predict the physical properties and relative reactivity of Ba and Sr Cs and Br ( elements from periodic table )

chemsitry

The molecular geometry of POCl3 is tetrahedral. What hybridization does this indicate for the central P atom? Why is the answer spy?

chemsitry

How many moles of silver chromate will be produced from 146 g of silver nitrate?

chemsitry

how do you determine the number of waters of hydration per formula unit? the general formula

11th grade chemsitry

If 150 g of water is heated from 3.0 celieus to 48.0 celieus how many joules of heat are needed

Chemsitry

You are given a colored solution that is labeled 1M. You need to prepare a solution from this that is 0.5 M. Describe your procedure in detail.

Chemsitry 130

Can someone please help me with the=is problem... In each of the following, determine which reactant is being oxidized and which is being reduced: A. Al(s) + O2(g) -----> Al2O3(s) B. Ca(s) + F2(g) -----> CaF2(s) Thanks so much for the help ;-)

Chemsitry

I just took my Chemistry midterm, and would like to know how to calculate my grade on the midterm with the curve. MEAN = 8.9 STANDARD DEVIATION = 2.9 MY SCORE = 7 Thank You!

Chemsitry

Use these data to estimate Avogadro's number. Palladium crystallizes with a face-centered cubic structure. It has a density of 12.0g/cm^3 , a radius of 138 pm , and a molar mass of 106.42 g/mol .

Chemsitry

For a particular redox reaction NO2– is oxidized to NO3– and Cu2 is reduced to Cu . Complete and balance the equation for this reaction in basic solution. Phases are optional.

chemsitry

1)Balance the following gas-phase reaction and 2) write its reaction quotient, Qc: CH4(g)+F2(g)......>>.....<<....... CF4(g)+HF(g) Include the physical states of all reactants and products in your balanced equation. Qc=

Chemsitry

What is the phase of a compound at 600 mmHg and 32oC if it melts at 35oC when pressure is 760 mmHg? Its triple point occurs at 200 mmHg and 36oC.

chemsitry

How would you figure-out which one is greater. You have 2.0 moles of H2O and 1.0 moles ofCO2 how would you get the answer.

chemsitry

Calculate the mass in grams of sodium bromide, NaBr, are needed to prepare 250.0 mL of a solution of sodium bromide that is 3.50% (m/v).

Chemsitry

Q1. How to find ions of a particular element.. Tell me the methods or procedure to do so? Q2. What are X-rays? Q3. What do u mean by "Irridated with X-rays? Q4. What do u mean by "radiation"?

chemsitry

complete the following sentence. For an experimental measurement, the experimental value minus the accepted value is called the _______. absolute error

chemsitry

1)100ml sample of solution that is 0.2M in both Naf and Hf has 4.0 ml of 1.0M hcl added to it. calculate the ph change of this soultion .ka =7.2*10^-4 2)40 ml of 0.32M benzoic acid if titrated with 60 ml of 0.2 M naoh. clacilate the ph of the resulting solution at the ...

chemsitry

Which of the following represent potential energy? a)a ball rolling down a hill b) stretched rubber band c) rowing a boat d) wind e) candy bar f) roller coaster at the top of hill

Chemsitry

What courses should you take in each grade 9,10,11,12 to help you become a pharmacologist. i need courses for each grade

Chemsitry

What is the pH of the buffer solution that results when 58.50 g of sodium acetate (NaCH3CO2) (Formula Mass = 82.02 g mol-1) is added to 1 litre of 0.45 mol L-1 acetic acid (CH3CO2H) ? Data: Ka for CH3CO2H = 1.8 x 10-5

Chemsitry

At 25 °C, only 1.9 g CaSO4 (MM = 136 g/mol) will dissolve in 2.00 L of water. Write the equilibrium expression and calculate the equilibrium constant for the reaction below. CaSO4 (s) ⇋ Ca2+ (aq) + SO42- (aq)

Chemsitry

Calcium Oxide is used to remove pollutant SO2 from smokestack gases. The ΔG° of the overall reaction CaO (s) + SO2 (g) + ½ O2 (g) ⇔ CaSO4 (s) is -418.6 kJ. What is PSO2 in equilibrium with air (PO2 = 0.21 atm) and solid CaO?

Chemsitry II

50.00 mL of 1.0 M HCl and 50.00 mL of 1.0 M NaOH are mixed. The temperature is observed to increase by 10.0 degrees C. How much energy (in J) was absorbed by the calorimeter? Assume a density of the reaction mixture of 1 g/mL. Specific heat of the solution is 5.00 J/g/degree C...

chemsitry

Why is the molecule you drew above more hydrophobic than dopamine? Describe the edit(s) that you made and how the change(s) make the new molecule more hydrophobic.

chemsitry

Why is the molecule you drew above more hydrophobic than dopamine? Describe the edit(s) that you made and how the change(s) make the new molecule more hydrophobic.

chemsitry

How will the osmotic pressure of an aqueous solution change as evaporation occurs? does it even change? or does it increase? evaporation will increase concentration, correct?

Chemsitry

Consider the equilibrium A(g)=2B(g)+3C(g) at 25 degrees Celsius. When A is loaded into a cylinder at 10 atm and the system is allowed to come to equilibrium, the final pressure is found to be 12.13 atm. What is the standard gibbs free energy of reaction for this reaction.

chemsitry

What ions are very important for the proper fuctioning of biological systems such as nerves and cells? A)alkali earth metals B)hydrogen ions C)oxygen ions D)nitride ions E)alkali metal ions

Chemsitry 2

a piece of nickel wire has a diameter of 0.568. if the nickel has a density of 8.90g/cc, how long( in meters) should you cut a piece of wire to obtain 0.0234 moles of nickel?

Math

We have an important chemsitry test due and I want to make sure that I do not mess up on my algebra. I am dealing with the integrated rate law, but my question is purely algebraically in nature. I hope, somebody can help me. 1) ln(A) = -kt+ln(B) solve for t solve for k solve ...

chemsitry

calculate the molarity of sodium in 12.4g of sodium acetate diluted in 100mL of ID water, and calculate concentration of both sodium and acetate ion in units of mg/mL,mg/L,and ug/mL?

chemsitry

how do you find the bond order of OH- and OH+? I know bond order = #bonded e- - #antibonding electron/2 im not sure how to find Oh- and Oh+

Chemsitry

If Kc = 6.38 × 105 for the reaction A(g) ⇀ ↽ 2B(g), what is Kc for the reaction written as 2B(g) ⇀ ↽ A(g)? How would I solve this?

Chemsitry

How many grams of ice at -24.3∘C can be completely converted to liquid at 23.9∘C if the available heat for this process is 4.82×103kJ ? For ice, use a specific heat of 2.01J/(g⋅∘C) and ΔHfus=6.01kJ/mol.

Chemsitry

During an experiment, a student adds 1.23 g of CaO to 200.0 mL of 0.500 M HCl. The student observes a temperature increase of 5.10 °C. Assuming the solution\'s final volume is 200.0 mL, the density if 1.00 g/mL, and the heat capacity is 4.184 J/(g·°C), calculate the heat of...

Chemsitry

Hi I have done this problem like 15 times when I find the mole I get .8 for HCL and .23 for Naoh and the equilibrium conc i get is negative. then I plug it in and get it wrong. Can someone please help me? Complete the table below: Note: Make simplifying assumptions, do not use...

Chemsitry

I don’t understand how to write this equation. Write an equation relating the concentration for a reactant A at t=0 to that at t=t for a first-order reaction. Define all the terms, and give their units. Do the same for a second- order reaction. -Would it be the rate law ...

chemsitry

What is the formal charge on each of the atoms in the Lewis structure of the PO4 (-3) charge? Draw another possible Lewis structure of the phosphate ion below. Formal charge on P is ? -how do I do this problem.

Chemsitry

Stomach acid is essentially 0.10 M HCl. An active ingredient found in a number of popular antacids is CaCO3. Calculate the number of grams of CaCO3 needed to exactly react with 250 mL of stomach acid. CaCO3(s)+ 2HCl(aq)= CO2(g)+ CaCl2(aq)+ H20(l)

chemsitry

100ml of h2s04 solution having molarity 1M and density 1.5g/ml is mixed with 400ml of water. calculate final molarity of h2s04 solution, if final density is 1.25g/ml. Answer 0.227M Who helps me to solve it Thank you a lot

chemsitry

hi I need help with this question please. 1. consider the decomposition of N2O5 in carbon tetrachloride(ccl4) at 45c 2N2O5(soln)-> 4NO2(g)+ O2(g) The reacion is first order in N2O5, with the specific rate constant 6.08*10^-4 per second.calculate the reaction rate under ...

Chemsitry

Alpha, beta particles and gamma rays. How does the atomic number and atomic mass number change when a radioisotope decays to produce alpha beta or gamma radiation.

chemsitry

A student performs this experiment and determines that 1.2 grams of CO2 was lost, but based on their limiting reagent calculations, 1.3 grams of CO2 was expected to be lost. What is the % error for this student's experiment?

Chemsitry

For the following equilibrium process: CO2 + H2 = CO + H2O The equilibrium concentrations of reacting species are: [CO]= .050 M; [H2]= .045 M; [CO2]= .086 M; [H2O]= .040 M. (a) Calculate Kc for the reaction (b) If we add CO2 to increase its concentration to 0.50 mol/L, what ...

Science(Chemsitry)

HNO3 used as a reagent has specific gravity of 1.42g/ml and contains 70% by strength HNO3. Calculate a)Normality Of Acid b)Volume of acid that contains 63g pure acid c)Volume of water required to make 1N solution from 2ml conc.HNO3

Chemsitry

When 3.75 g of a nonelectrolyte solute is dissolved in 405 mL of water at 25 °C, the resulting solution exerts an osmotic pressure of 897 torr. What is molarity? I found molarity to be 0.048. What is the number of moles of solute? to find moles, I multiplied it by .405 and ...

Chemsitry

What is the ∆G for the following reaction under standard conditions (T = 298 K) for the formation of NH4NO3(s)? 2NH3(g) + 2O2(g) NH4NO3(s) + H2O(l) Given: NH4NO3(s): ∆Hf = -365.56 kJ ∆Sf = 151.08 J/K. NH3(g): ∆Hf = -46.11 kJ ∆Sf = 192.45 J/K. H2O(...

AP Chemsitry

A solution of an unknown monoprotic weak acid was titrated with 0.100 M NaOH. The equivalence point was reached when 37.48 ML of base had been added. From a second buret, exactly 18.74 of 0.100 M HCl were added to the titration solution. The pH was then measured with a pH ...

chemsitry

How many grams of propane (C3 H8 ) will react with 3.29 L of O at 1.05 atm and -34°C? i know the balanced eqn is 1C3H8 + 5 O2 -----> 3CO2 + 4H20 and that PV=nrt , with T= -34 + 273.15 = 239.15K. n=(PV)/(RT) (F=for O2). = 0.176 mol O2 0.176 mol O2 * (1mol C3H8 / 5mol O2) * ...

Chemsitry - Van Der Waals

The constants "a" and "b" in the van der waals equation are "empirical coefficients". What exactly does that mean? Show that the units for "a" and "b" are appropriate for the the Van der Waals equation?

Chemsitry

Calculate the molar mass of an unknown molecular compound mixed with solid camphor C10H16O, heated and then cooled giving the following data. show all steps in calculation. mass of unknown: 0.195 g Tf(camphor)= 179.8 degree C Kf(camphor)=-40.0 degree C/m mass of camphor-25.03g...

Chemsitry

A mixture of 10.00 mL of H2SO4 and 30.00 mL of HCl required 20.00 mL of 2.500 M NaOH for complete reaction. When 30.00 mL of H2SO4 and 10.00 mL of HCl were used, 28.00 mL of 2.500 M NaOH were required. What were the concentrations of the acids? [Both were 1.000 M] H2SO4(aq) + ...

CHEMSITRY

IN THIS EXPERIMENT YOU FILL A PREFROM WITH WATER AND PUT A DRINKING STRAW INTO THE PREFROM AND USE CLAY TO SEAL THE OPENING. It is important to recall that when you first tried it, you were unable to drink, but a small amount of water entered the straw. When the water goes ...

chemsitry

A graduated tube, sealed at the upper end has a mercury leveling bulb connected to the lower end. the gas volume is 25.ml, when the mercury level is the same in both ends. the barometric pressure is 732 mm Hg. What is the gas volume when the mercury level on the open side is ...

Chemsitry

Nitrogen dioxide, a pollutant in the atmosphere, can combine with water to from nitric acid. One of the possible reactions is shown below. Calculate ∆G0 and Kp for this reaction at 25oC and comment of on the spontaneity of the reaction (MUST plot the data and find ...

Chemsitry

Tris is an abbreviation for tris (hydroxymethyl) aminomethane, which is a weak base. Calculate how many grams of tris (mw=121.14g/mol) are needed to make 25mL of 0.10M tris solution. Calculate how many mL of 0.25M HCl are needed to convert half of the moles of tris present in ...

Chemistry

We're doing gas problems in chemsitry. I have no idea where to even begin on this problem: Air is 20% oxygen and 80% nitrogen. What is the mass of air in an automobile tire of 19.7 L and internal pressure of 46.7 PSI at 24 degrees celsius? (That pressure is the same as the 32 ...

chemsitry

c. Use the enthalpy diagram provided above and apply Hess’s Law to determine the standard enthalpy of formation for C12O36H20N12 (s) using the results from part (a) and the following values: The standard enthalpy of formation of gaseous carbon dioxide is -393.5 kJ/mol The ...

Chemsitry

What is the purpose of cell matching? (1 mark) I've been researching for quite a long time now. This question relates to using spectrometry. Can anyone help me? Thanks! I let this question go yesterday because I connected it with cells is biology. On rereading today I see it ...

Chemsitry

The Ksp of PbBr2 is 6.60× 10^–6. What is the molar solubility of PbBr2 in pure water? What is the molar solubility of PbBr2 in 0.500 M KBr solution? What is the molar solubility of PbBr2 in a 0.500 M Pb(NO3)2 solution?

Organic Chemsitry

By knowing the natural abundance of minor isotopes, it's possible to calculate the relative heights of M+ and M+1 peaks. If natural abundances are 12C - 98.9% and 13C - 1.10%, what are the relative heights, to the nearest 0.1%, of the M+ and M+1 peaks in the mass spectrum of ...

chemsitry

Consider the diprotic acid H2A with K1 1*10^-3 and K2= 1*10^-9 . Find pH, [H2A], [HA], and [A2-] for a .2000M solution of H2A b)Find pH, [H2A], [HA], and [A2-] for a .200M solution of HA- c) Find pH, [H2A], [HA], and [A2-] for a .200M solution of A-

chemsitry

A sample consisting of 0.025 mol of a solid compound is placed inside a metal cylinder. The cylinder was immersed in a water bath consisting of 10.00 kg of water at an original temperature of 25.00 °C. When the compound decomposes, the temperature of the water rises to 29.52...

chemsitry

calculate the molarity of sodium in 12.4g of sodium acetate diluted in 100mL of ID water? and calculate concentration of both sodium and acetate ion in units of mg/mL,mg/L,and ug/mL? and calculate concentration of both sodium and acetate ion in units ppm,ppd?

Chemsitry

Which of the following is NOT true about the thermodynamic standard state? A. A solid is in its standard state when the atmospheric pressure is 1.00 atm and the temperature is 25C. B. An aqueous solution is in its standard state at a concentration of 1.00 M. C. A gas is in its...

Chemsitry

Check my work? What is the approximate pH of a 0.05 M solution of HSCN that has a Ka of 10-4? HSCN -> H+ + SCN- --------------------------- The equation for calculating pH is pH = -log [H+] Now we need to find H+ and solve. [HSCN] = 0.05 M the molarity Ka = [H+][SCN-]/[HSCN...

chemsitry

home / study / questions and answers / science / chemistry / make sure to answer both parts: 1)balance the following ... Your question has been posted. We'll notify you when a Chegg Expert has answered. Post another question. . Question Edit question make sure to answer both ...

chemsitry

You have been provided 100mL of a 1000ug/ml barium standard what volume of this standard must be diluted into 50mL of ID water to produce a 30 ug/ml standard ? if you given a full 100mL of the same standard provied calculate the amount of standard and final volume required to ...

chemsitry

acetylsalicylic acid (aspirin) HC9H7O4 is the most widely used pain reliever and fever reducer. Find the PH of 0.040 M aqueous aspirin at body temperature (Ka at 37 C = 3.6 x 10-4) is this correct? initial concentration is 0.040 M. let change in concentration to equilibrium ...

Chemsitry II

mole fraction is equal to partial pressure divided by the total pressure Total pressure= sum of partial pressure use PV=nRT where n= number of moles equation become PV/RT=n make sure to convert the temperature to Kelvin and to use 0.0821 for R. V=volume, P=total pressure The ...

Chemsitry

Which of the laws of thermodynamics provides a criterion for spontaneity? the zeroth law, the first law, the second law, and the third law? This site will give you zeroth, first, second, and third laws. You may need to scroll down a little but it on the right of center of the ...

chemsitry

b. The decomposition reaction may be written in this form: C12O36H20N12 (s) → 12CO2 (g) + O2 (g) + 6N2 (g) + 10H2O (l) In the enthalpy diagram below, the arrows represent standard enthalpy reactions. (3) denotes the standard enthalpy of decomposition of C12O36H20N12 (s...

Chemsitry (Check)

Fill In The Blanks I have Sharing for the first blank and Single for the second. A _______ pair of valence electrons consitutes a _______ covalent bond. Shared/Double. See http://www.chemguide.co.uk/atoms/bonding/doublebonds.html I would have gone with shared and single, also...

Chemsitry II

The partial pressure of CH4(g) is 0.185 atm and that of O2(g) is 0.300 atm in a mixture of the two gases. a) What is the mole fraction of each gas in the mixture? b) If the mixture occupies a volume of 11.5 L at 65 degress C, calculate the total number of moles of gas in the ...

chemsitry dr Bob

Magnesia (MgO(s)) is used for fire brick, crucibles and furnace linings because of its high melting point. It is produced by decomposing magnesite (MgCO3(s)) into at around 1200oC Write a balanced equation for the magensite decomposition being sure to include states for the ...

chemsitry dr Bob

Magnesia (MgO(s)) is used for fire brick, crucibles and furnace linings because of its high melting point. It is produced by decomposing magnesite (MgCO3(s)) into at around 1200oC Write a balanced equation for the magensite decomposition being sure to include states for the ...

Chemsitry

Hello. I'm not n=sure about these answers so i was wondering if someone could check them out? 27, A: Which is a stronger acid - sulfuric or carbonic acid? (Answer: Sulfuric acid.) 27, B: Imagine you have two glasses. One contains a solution of carbonic acid. The other contains...

Physics - Ionic bonding

Hello My exams are coming I'm a straight A student .. the problem however is : My textbooks , teacher and every piece of work that he gives us is complicated can someone explain me how Ionic Bonding works and when we're taking about this table here can someone explain it to me...

Chemsitry

How do you find the amount in moles of excess reactant that reamins Please retype that, minding your spelling. =) Can you please show me how to determine the amount in moles of excess reactant that remains Sorry about the mistakes =) This is part of an excess reagent problem. ...

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