Tuesday
May 5, 2015

Posts by vivian


Total # Posts: 129

gravimertic prob
an organic pesticide (mw 183.7) is 8.43% cl. a 0.627g sample containing the pesticide plus inert material containing no chloride was decomposed with metallic sodium in alcohol. the liberated chloride ion was precipitated as agcl weighing 0.0831g. calculate the percentage of ...
April 26, 2015

gravimetric
in the gravimetric determination of barium in BaCrO4, what weight of sample must be taken so that the weight of the precipitate in milligrams multiplied by 100 will equal the % Ba in the sample?
April 20, 2015

gravimetric prob
689.64 mg is the new ppt? am i right?
April 20, 2015

gravimetric prob
A sample of freshly precipitated silver chloride weighs 704.7mg. Before the solution can be filtered and washed 10.0mg of AgCl is photodecomposed. After the precipitate is filtered and washed another 10.0 mg of AgCl is photodecomposed. Calculate the weight of the precipitate.
April 20, 2015

gravimetric prob
Difference between initial and final perchlorate(18.6137-18.6448) = 0.0311 ascarite(16.8425-16.9098)= 0.0673 %H= (0.0311x2x1.00784/44.00766)/947.4×100= 0.000150355 %C=(0.0673x12.0096/44.0076)/947.4x100=0.001938572 0.000150355x1mol/1.00784= 0.000148866 0.001938572x1mol/12...
April 20, 2015

gravimetric prob
A pure organic compound weighing 947.4mg was heated in a stream of oxygen. The effluent gas was swept successively through a tube of magnesium perchlorate dessicant weighing 18.6137g and a tube of Ascarite weighing 16.8425g. After several minutes the tubes were sealed and ...
April 20, 2015

Further maths
Two functions f and g are defined over the set of R of real numbers as follows: f:x=2x-3 g:x=xsquare+5 find f[g(x-1)]
April 18, 2015

Chemistry
How much energy in joules is required to heat 25g of ice from -10.0 C to 0.0C and change it to water. The specific heat is 2.09J Please explain
April 16, 2015

Phsyics HELP!
A car accelerates uniformly from +10.0 m/s to +50.0 m/s over a distance of 225 m. How long did it take to go that distance? Show all your work, including the equation used, given and unknown quantities, and any algebra required. Make sure your answer has the correct number of ...
March 5, 2015

Physics
A plane traveling at 200.0 km/h attempts to land on a 250 m runway. The plane’s engines and brakes accelerate uniformly at –7.0 m/s2. Will the plane be able to land safely? Show all your work. Include any equations used, including the given and the unknown. Show all ...
March 5, 2015

math
In Carl's drawer, he has white,gray,and black socks. In his closet,he has black brown,and blue shoes. I need to make a diagrdiagram to display the sample space for Carl choosing a sock and shoe color. Is this right White/black,brown blue Gray/black,brown,blue Black/black ...
January 21, 2015

physics
a man steps out of a rowboat into a dock. The man has a mass of 80 kg and moves forward with a velocity of 1.5 m/s. If the boat has a mass of 120 kg. and was initially at rest, what is its final velocity?
November 26, 2014

Chemistry
Construct a cycle with the following steps: Begin with: 1 mol ideal monatomic gas at 300 K and 1 bar. Point A. 1. Isothermal reversible expansion till volume gets twice its original value. Point B. then, 2. Irreversible adiabatic expansion against P_ext=0.25 bar till P_ext=...
October 6, 2014

Chemistry
During recrystallization, an orange solution of a compound in hot alcohol was treated with activated carbon and then filtered through fluted paper. On cooling, the filtrate gave gray crystals, although the compound was reported to be colorless. Explain why the crystals were ...
September 28, 2014

Physics
A ball is thrown at 41° below the horizontal from a rooftop of height 65 m. It lands 2 s later. Find: Find: a) its initial speed b) the point of impact with the ground; m from the base of the building c) the angle at which it hits the ground. ° below the horizontal
September 28, 2014

physics
A ball is thrown horizontally at 15 m/s from a clifftop 60 m above the sea level. Find: a) the time to land; b) the angle at which it hits the water; ° below the horizontal c) the speed at which it hits the water. m/s
September 28, 2014

Physics
An electron in an atom has a speed of 2.2 × 10^6 m/s and orbits the nucleus at a distance of 5 × 10^-11m.a)What is its centripetal acceleration? b)A neutron star of radius 17 km is found to rotate at 5 revolutions per second. What is the centripetal acceleration of...
September 28, 2014

math
What is the smallest six digit number you can make that would round to 126000?
September 4, 2014

soc 313
ella miller and her family issues
May 19, 2014

math
in an album, the ratio of the number of local stamps to the number of foreign stamps was 7 : 4. When Lucy gave away 8 local stamps and 8 foreign stamps, there were 1.8 as many local stamps as foreign stamps in the album. find the total number of stamps Lucy had in the end.
March 5, 2014

Math
Two fishing boats depart a harbor at the same time, one traveling east, the other south. The eastbound boat travels at a speed 7 mi/h faster than the southbound boat. After seven hours the boats are 91 mi apart. Find the speed of the southbound boat.
January 23, 2014

physics
sin 27=0.45=59/x => x=115.69 tan27=0.51=59/y => y=131.11 ratio=y/x => ratio= 1.1
November 25, 2013

9th grade Geography
what shape describes the united states
August 21, 2013

Math
lee and his family are planning a hiking trip on the Appalachian trail. they are packing food in 2lb bundles. how many bundles can they make with 36 lb of food? write a number sentence to help you solve this problem.
May 20, 2013

college algebra
i need help with elimination and substitution linear equation
May 5, 2013

Science (chemistry)
Pls help.. Q: prepare a table of value for acid-base titration using 26.40cm^3 as end point
March 15, 2013

Chemistry
Two liquids A and B have vapor pressures of 71.3 and 131 mmHg, respectively, at 25 degrees Celsius. What is the total vapor pressure of the ideal solution made up in the following concentrations? 1.00 mole of A and 1.00 mole of B 2.00 moles of A and 5.00 moles of B
December 7, 2012

Algebra
if a ball standing on four legs wetght 1,200 pounds,how much will this bull weigh when standing on three legs
August 23, 2012

Hypothesis - Statistics
At one school, the average amount of time that tenth-graders spend watching television each week is 18.4 hours. The principal introduces a campaign to encourage the students to watch less television. One year later, the principal wants to perform a hypothesis test to determine...
July 28, 2012

math
A researcher wishes to estimate the proportion of college students who cheat on exams. A poll of 490 college students showed that 33% of them had, or intended to, cheat on examinations. Find the margin of error for the 95% confidence interval.
July 15, 2012

math
A government survey conducted to estimate the mean price of houses in a metropolitan area is designed to have a margin of error of $10,000. Pilot studies suggest that the population standard deviation is $70,000. Estimate the minimum sample size needed to estimate the ...
July 15, 2012

programming in c++
a program in c++ that accepts exam marks for 10 students and stores them in an array.the program should then calculate and utput the average marks for the class.and give an account of marks below average and output all marks above average.
June 19, 2012

chemistry
A mixture of 16 g of salt and 47 g of baking soda is poured into 296 ml of water. What is the total mass of the mixture in grams?
June 14, 2012

Geometry
If the two lines are perpendicular, what is x + y 2y- 10 2x+1
May 22, 2012

chemistry
Calculate the theoretical pH when 5.00 ml of 0.0100 M HCl is added to 30.00 mL of deionized water.
April 29, 2012

math
explain how to compare 0.34 and 0.27
April 26, 2012

math
Mia is stacking copies of a new book in a square-pyramid display by the front window of her bookstore. for each consecutive layer, she places one book where four meet. A. I the bottom row of the display has 144 books and there is one book on the top, determine how many rows of...
March 14, 2012

Calculus 2
how do we know if the curve theta = pi/2 is a circle, or semicircle, or spiral? I've tried to change the curve to x and y, but both sides of the equation are the same, and tan(pi/2)=infinity.
February 28, 2012

chemistry
2 solutions of equal amounts in a u-tube are separated by a semipermeable membrane. The level os the (more/less( concentrated will rise. I think the answer is (more) but I'm not sure. What do you think?
February 9, 2012

Chemistry
Which of the following solutions will have a higher boiling point? A. 1m C6H12O6 B. 1m NaCl C. 1m MgCl2 D. 1m AlCl3 And pls explain why it is. Thank you so much!!
February 9, 2012

Calculus
∫[(x+3)/(x^2 +9)]=????? Can you give me a hint for solving it?
February 8, 2012

chemistry
The freezing-point depression is -0.930 Celsius degree. Determine the molality of the solution of an unknown nonelectrolyte in water. Please help!! I do not understand this problem!
February 7, 2012

arithmetic
The first three terms in an arithmetic are given by x,4x+5 and 10x-5.find the value of x.
January 21, 2012

Gravi prob chem
in the gravimetric determination of barium in BaCrO4, what weight of sample must be taken so that the weight of the precipitate in milligrams multiplied by 100 will equal the % Ba in the sample?
January 16, 2012

organic chemistry--please help me!!!
Give equations to show how sulfuric acid can convert 4-methylcyclohexene into a mixture of four isomeric c7H12 compounds(including starting material). Predict the relative amounts of each isomer.
October 31, 2011

Maths
Calculate the volume and curved surface area of a cone 14cm in base diameter and 24cm high
October 26, 2011

Maths
A right pyramid on a base 4cm square has a slant edge of 6cm.calculate the volume of the pyramid
October 26, 2011

organic chemistry --please help me!!!!!!!!!!!!!!!
Calculate the theoretical yield for the bromination of bothstilbenes and cinnamic acid, assuming the presence of excesspyridinium tribromide. cinnamic acid - 150 mg cis-stilbene - 100 μL trans- stilbene - 100 mg pyridinium tribromide - 200-385 mg
October 20, 2011

organic chem
How do injector temperature and detector temperature affect retention time of a compound in gas chromatography?
October 7, 2011

organic chem
An unknown compound melted at 131-133°C. It is thought to be one of the following compounds(mp,°C): trans-cinnamic acid (133-134); benzamide(128-130); DL-malic acid(131-133); or benzoin(135-137). The mixture melting points of the unknown compound with each of the test ...
September 8, 2011

organic chem
in simple distillation or fractional distillation do the changes in temperature occur more gradually? and why?
September 6, 2011

organic chem
why should we notify the laboratory instructor of any incidents that occur in laboratory?
September 1, 2011

organic chem
what steps should we do if a large bottle of acetone is broken and spilled in the laboratory?
September 1, 2011

organic chem
what steps should we do if ethanol in a beaker ignites in the laboratory?
September 1, 2011

Business Math
Earl wants to retire to San Diego when he is 65, he is now 50. He will need $300,000.00, how much would he have to invest today @6% interest compounded semiannually to meet his goal?
May 18, 2011

business math
Greg will need $218,000.00 in 15yrs for college bills, how much does he have to invest today @8% compounded semiannually?
May 18, 2011

chemistry
i checked through my work and I found out i didn't do square root for the x^2....thats why my answer was double 6.011.
May 15, 2011

chemistry
i worked through it just dont know it i did it right...
May 15, 2011

chemistry
Calculate the pH at the equivalence point for the titration of a solution containing 1250.0 mg of hilariamine (MW = 92.5 g/mol, Kb = 8.1×10−4) with 0.1000 M HCl solution. The volume of the solution at the equivalence point is 175.0 mL. (I got the answer to be 12....
May 15, 2011

chemistry
Calculate the pH at the equivalence point for the titration of a solution containing 1250.0 mg of hilariamine (MW = 92.5 g/mol, Kb = 8.1×10−4) with 0.1000 M HCl solution. The volume of the solution at the equivalence point is 175.0 mL. (I got the answer to be 12....
May 15, 2011

chemistry
i got 11.5 but im not sure because the problems i did before i had to change to ka first and that was the pH and got those answers right...but i dont understand why i have to do it this way though its the right way...quest is saying its wrong..
May 13, 2011

chemistry
What would be the pH of a 0.563 M solution of ammonia (NH3) at room temperature? The Kb of ammonia is 1.78 × 10−5. 1. 2.5 2. 7 3. 9 4. 4.5 5. 11.5 ( I did this problem but apparently 4.5 isnt the answer)
May 13, 2011

chemistry
What would be the pH of a 0.563 M solution of ammonia (NH3) at room temperature? The Kb of ammonia is 1.78 × 10−5. 1. 2.5 2. 7 3. 9 4. 4.5 5. 11.5 ( I did this problem but apparently 4.5 isnt the answer)
May 13, 2011

chemistry
Consider the ionization constants hypochlorous acid (HOCl) : Ka = 3.5 × 10−8; ammonia (NH3) : Kb = 1.8×10−5. A solution of ammonium hypochlorite (NH4OCl) is 1. acidic, because the cation hydrolyzes to a greater extent than the anion. 2. basic, because ...
May 13, 2011

chemistry
The problem didnt include Ka
May 12, 2011

chemistry
i did it and used 6.2E-10. my answer wasnt there so i was wondering if i did something wrong..i got 7.11 for pH
May 12, 2011

chemistry
What is the pH of 8.94 × 10−6 M HCN(aq), ignoring the effect of the autoprotolysis of water? 1. 7.17923 (basic; thus not reasonable) 2. 6.03594 3. 7.30027 (basic; thus not reasonable) 4. 5.50032 5. 7.38101 (basic; thus not reasonable) 6. 5.18207 7. None of these
May 12, 2011

chemistry
Calculate the pH of the solute in an aqueous solution of 0.0047 M codeine, if the pKa of itsconjugate acid is 8.21. What is the percentage protonation of the solute?
May 12, 2011

chemistry(Acid&Base)
is the answer 2)5.3....
May 12, 2011

chemistry(Acid&Base)
Calculate the solubility product of calcium hydroxide if the solubility of Ca(OH)2(s) in water at 25◦C is 0.011 M. Choices: 1. 1.1 × 10−5 2. 5.3 × 10−6 3. 2.7 × 10−6 4. 1.5 × 10−8 5. 1.2 × 10−4
May 12, 2011

history
What ultimately changes John Adams's mind and favor of American revolution?
April 26, 2011

history
how did john adams feel about the behaviors of son of liberty?
April 16, 2011

biology
what are examples of enzymatic disorders? How do the diseases involve enzymatic reactions?
April 6, 2011

general biology
why is yeast used in the experiment of respiration?
April 5, 2011

Physic
how does the M.A and the I.M.A of the inclined plane vary with the inclination angle?
March 24, 2011

Physics
how does the MA and the IMA of the inclined plane vary with the inclination angle?
March 24, 2011

Physics
how does the MA and the IMA of the inclined plane vary with the inclination angle?
March 24, 2011

Physics
how does the M.A. and the I.M.A of the inclined plane vary with the inclination angle?
March 24, 2011

physics
how does the M.A. and the I.M.A. of the inclined plane vary with the inclination angle?
March 24, 2011

literature-help me PLEASE?
Explore the theme of loneliness and discuss how the writer has conveyed this to the reader through their use of language and style.The poems, Night Waitress by Lynda Hull, The Lady in The Pink Mustang by Louise Erdrich, and Those Winter Sundays by Robert Hayden. please help me...
March 11, 2011

literature
Can sadness be loneliness?
March 10, 2011

literature-help me PLEASE?
how does Eudora Welty use dialogue to establish characters and character relationship in A Visit of Charity?
February 21, 2011

History
What creatures did the europeans introduce in the new world?
February 17, 2011

english--Please help me!!!
"Most Americans would follow a thinker rather than become one themselves." Please help me explain that sentence, and also give me examples!!!who is a thinker?? in what situation do they follow the thinker, and why????
January 27, 2011

math
s=1/2(a-b)x find b
January 9, 2011

math
I just did 180m/1 day times 1 day/1440 minutes Hope this hdlps
January 5, 2011

Chemistry
what is a common physical property of ester?
December 4, 2010

social studies
What did the Spanish hope to do in California?
November 30, 2010

chem
Ka=1.8x10^-5. How do you calculate the value of pKa?
November 9, 2010

chemistry
how do I plot absorbance vs concentration and transmittance %T vs concentration on the same graph??
November 6, 2010

math
In recent years, Juresic Transportation purchased three used buses. Because of frequent turnover in the accounting department, a different accountant selected the depreciation method for each bus, and various methods were selected. Bus Acquired Cost Salvage Value Useful Life ...
November 6, 2010

business
In recent years, Juresic Transportation purchased three used buses. Because of frequent turnover in the accounting department, a different accountant selected the depreciation method for each bus, and various methods were selected. Bus Acquired Cost Salvage Value Useful Life ...
November 6, 2010

math
Information related to Hermesch Company for 2011 is summarized below. Total credit sales $2,200,000 Accounts receivable at December 31 825,000 Bad debts written off 33,000 What amount of bad debts expense will Hermesch Company report if it uses the direct writeoff method of ...
November 1, 2010

Sociology-please help me!
why is the gap between the rich and the poor growing according to Robert Reich in "What happned to the American Social Compact"?
November 1, 2010

business
Tavarez Company assembled the following information in completing its July bank reconciliation: balance per bank $15,280; outstanding checks $3,100; deposits in transit $5,000; NSF check $320; bank service charge $100; cash balance per books $17,600. As a result of this ...
October 26, 2010

business
A petty cash fund of $100 is replenished when the fund contains $3 in cash and receipts for $93. The entry to replenish the fund would debit Cash Over and Short for $4. credit Miscellaneous Revenue for $4. credit Cash Over and Short for $4. debit Miscellaneous Expense for $4.
October 26, 2010

business
Internal controls are concerned with?
October 26, 2010

business
Listed below are five procedures followed by The Beat Company. Several individuals operate the cash register using the same register drawer. A monthly bank reconciliation is prepared by someone who has no other cash responsibilities. Ellen May writes checks and also records ...
October 25, 2010

math
On May 31, 2011, James Logan Company had a cash balance per books of $6,781.50. The bank statement from Farmers State Bank on that date showed a balance of $6,404.60. A comparison of the statement with the cash account revealed the following facts. The statement included a ...
October 25, 2010

business
On May 31, 2011, James Logan Company had a cash balance per books of $6,781.50. The bank statement from Farmers State Bank on that date showed a balance of $6,404.60. A comparison of the statement with the cash account revealed the following facts. The statement included a ...
October 25, 2010

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