# A latex balloon, wall thickness 3.091 x 10-4 m, contains helium at a concentration of 0.72 kg m-3. Under these conditions the total surface area of the balloon is 0.17 m2. The diffusion coefficient of He in latex at room

13,119 questions, page 88
1. ## Physical sciences

Potassium dichromate,concentrated nitric acid 12m,concentrated sodium hydroxide 12.5m and water.set up an experiment to investigate the effects of changing concentration on an equilibrium mixture

asked by Tshephiso on May 23, 2011
2. ## Chemistry

Someone please help me on this question! A person’s blood cholesterol level is 245 mg/dL. (1g=1000mg; 1L=1000mL). Show all calculations. What is the cholesterol concentration in ppT (part per thousands) and ppm (parts per million)?

asked by Anonymous on July 22, 2019
3. ## Chemistry

The approximate concentration of hydrochloric acid, in the stomach is 0.17M .calculate the mass of the following antacids required to neutralize 50mL of this acid; 1.) bicarbonate of soda, NaHCO3 2.) aluminum hydroxide, Al(OH)3

asked by Katie on November 16, 2017
4. ## Chemistry

What is the pH of the solution created by combining 2.40 mL of the 0.10 M NaOH(aq) with 8.00 mL of the 0.10 M HC2H3O2(aq)? Can somebody explain how to do this? I am stuck. I've tried solving for H+ concentration. I got .00024M and subtracted it from [OH-].

asked by John on May 2, 2010
5. ## Chemistry

Calculate the hydronium and hydroxide concentration of a solution made by mixing 100 mL 0.020 mol/L NaOH and 25.0 mL of 0.040 mol/L HCl. I'm having trouble knowing where to start with this question.

asked by Hal on December 1, 2015
6. ## Chemistry

I recently calculated for concentration needed to my solution to get -1.5MPa PEG 6000 and I got 0.05g PEG/g H2O but I don't know how to convert this to moles/ L which is more familiar to me and more easier for preparing solutions. Please help.Thank you

7. ## chem

For a mixture of 12.0mL of 0.004. M AgNO3 and 8.0mL of 0.0025 M K2CrO4, a colorimetric measurement of CrO4-2 in the equilibrium supernatant liquid found its concentration to be 1.5*10^-4 M. Calculate the Ksp of Ag2CrO4.

asked by jerry on July 9, 2012
8. ## chemistry

Which response has both answers correct? Will a precipitate form when 250 mL of 0.33 M Na2CrO4 are added to 250 mL of 0.12 M AgNO3? [Ksp(Ag2CrO4) = 1.1 „e 10¡V12] What is the concentration of the silver ion remaining in solution?

asked by farahn on November 30, 2015
9. ## Chemistry lab

I mixed 10 mL of 9mM KI with 5 mL of 0.9mM in a flask, and then added it to a beaker that contained 10 mL of 45 mM KBrO3, and 10 mL of 90mM HCl. This reaction took 61.60 seconds to complete. I think I need to find the change in concentration, but don't

asked by Calley on April 8, 2014
10. ## chemistry

a solution (S) is prepared by dissolving 50.0 g calcium chloride in 250 ml volumetric flask wich is then filled with distilled water up to the line mark. calculate the molar concentration of solution (S)

asked by alia on March 10, 2013
11. ## equilibrium question

For the reaction N2(g)+o2(g)2NO(g), you have the initial concentration [N2]=0.03 and [O2]=0.08 Keq for the reaction at this temperature is 5.7*10^-5. What are the equilibrium concentrations for N2, O2, and NO? Please help me with this!

asked by Chrissy on April 13, 2007
12. ## Chemistry

The average human body contains 5.30L of blood with a Fe2+ concentration of 2.30×10−5M . If a person ingests 11.0mL of 15.0mM NaCN , what percentage of iron(II) in the blood would be sequestered by the cyanide ion?

asked by CHEMISTRY on March 14, 2009
13. ## pre-calculus

Steve, The following rational function describes concentration in blood of a certain medicine taken once depending on time, find: A. the horizontal asymptote B. the vertical asymptote C. describe their possible meaning ( I only need help with C).

asked by Sharon on June 20, 2015
14. ## Math

For questions 8-10, remember to show all the steps that you use to solve the problem. Be sure to use the text box where the question mark first appears to show your mathematical work. You can use the comments field to explain your work. Your teacher will

asked by Connectionshelp on May 1, 2019

H2(g) + CO2(g) H20(g) + CO(g) When H2(g) is mixed with CO2(g) at 2,000K, equilibrium is achieved according to the equation above. In one experiment, the following equilibrium concentrations were measured: [H2]=0.20 M [CO2]=0.30 M [H2O]=[CO]=0.55M a) What

asked by sara on February 25, 2007

http://en.wikipedia.org/wiki/Cyanobacteria Scroll to photosynthesis and read. Then think about how most plants and algae use chloroplasts to photosynthesise. Cellular examination of a cyanobacterium and a diatom reveals that the diatom has (which

asked by Lance on March 12, 2007

Hello, could you guys let me know if this looks right? Thanks in advance. A ball is fired at a speed of 8 m/s at 20 degrees above the horizontal from the top of a 5m high wall. a) what is the total velocity at the maximum height? b) how far from the

asked by Timothy on October 3, 2016
18. ## Math

A rancher has 360 feet of fencing to enclose two adjacent rectangular corrals. The wall separating the two corrals consists of a single fence. them. What dimensions for one of the individual corrals will produce the largest total area? Your answer is

asked by George Carl on February 27, 2018
19. ## English

1.The clowns and jugglers (has, have) always been my favorite performers. 2.Neither pencils nor an eraser (are, is) permitted. 3.All of the boats in the harbor (belong, belongs) to the village. 4.Either the wall clock or our wristwatches (tell, tells) the

asked by Tracy on December 9, 2010
20. ## Physics

On the Round Up at the amusement park, people stand in a cylindical "room" of radius 6.18 m and the room rotates until it reaches a rotational frequency of 0.89 revolutions per second. At this point, the floor drops out. What is the minimum coefficient of

asked by Kyle on May 10, 2016
21. ## physics

Q:What happens to the pressure of particles in the container when it is heated.explain. Q:A pressure of 2200Kpa is exerted by the particles in the container on the wall of area 25cm2. find the force exerted by the particle.

asked by saffa on December 10, 2011
22. ## geometry

the width of a rectangular room is 4m wider tan its height and the length is 8m wider than the width .if the total area of the wall is 512m square, find the length of the room.

asked by Anonymous on June 24, 2012
23. ## Physics

A tennis ball is hit into the wall with a speed of 26 m/s. If it rebounds with a speed of 24 m/s, how much energy was lost in the collision? mass of tennis ball = 0.059 kg A) 6 joules B) 1 joule C) 3.0 joules

asked by Mia on June 1, 2019
24. ## DrBob222

A boy is blowing a whistle of frequency 536 Hz and walking toward a wall with a speed of 1.64 m/s. What frequency of the reflected sound will the boy hear if the speed of sound is 343 m/s? 532 Hz

asked by Jon on April 5, 2008
25. ## Math

Two ladders are the same distance from the base of a wall. The longer ladder is 15m long and makes an angle of 58 with the ground. if the shorter ladder is 12.6m long, what angle does it make with the ground?

asked by Emily on May 13, 2015
26. ## chemistry

Could someone help me with this please? In chemistry, we did a lab in which he put brands of commerical vinegar in a microplate. We put in 10 drops of each vinegar in each plate thinger then we added 1 drop of phenolphthalein and then put in as many drops

asked by Jeffrey on May 14, 2007
27. ## Chemistry

I am super confused when it comes to these types of questions! Can someone check my work? None of my answers matched those of my teacher when she read them this morning for last night's homework. Please help! 1. Consider the following equilibrium reaction:

asked by Samantha on May 18, 2009
28. ## Chemistry

Consider the following reaction, equilibrium concentrations, and equilibrium constant at a particular temperature. Determine the equilibrium concentration of SO2(g). 2SO2(g)+O2(g)=2SO3(g) Kc=1.7*10^8 [SO3]aq=0.0034 M [O2]aq=0.0018 M

asked by Timothy urgent need on December 10, 2013
29. ## Chemistry

When a sample of I2(g) (0.07249 mol/L) is placed in 130.0 L reaction vessel at 865.0 K and allowed to come to equilibrium the mixture contains 0.1110 mol/L of I(g). What concentration (mol/L) of I2(g) reacted? I2(g) = 2I(g)

30. ## College Chemistry

Consider the following reaction, equilibrium concentrations, and equilibrium constant at a particular temperature. Determine the equilibrium concentration of SO2(g). 2SO2(g)+O2(g)=2SO3(g) Kc=1.7*10^8 [SO3]aq=0.0034 M [O2]aq=0.0018 M

asked by Timothy urgent need on December 10, 2013
31. ## Chemistry

a titration experiment 20 mL solution of hydrochloric acid required 15.2mL of a .879 M barium hydroxide solution. What was the molar concentration of the HCl solution?

asked by Chris on October 11, 2011
32. ## physics

An rectangular above-ground swimming pool is 9 m long and 4 m wide. The pool wall has a constant height of 3 m above the ground. Take atmospheric pressure to be 1 atm = 105 Pa and g = 10 m/s2. (a) Calculate the weight of the air that fills the pool when

asked by kelly on March 20, 2011
33. ## Physics

A horizontal spring with K = 110 N/m has one end attached to the wall. A 250g block is pushed onto the free end, compressing the spring by 0.190 . The block is then released, and the spring launches it outward. Neglecting friction, what's its speed when it

asked by Eman on October 12, 2011
34. ## science

a framed picture of weight 15N is to be hung on a wall using a price of string . the end of the string are tied to two points ,0.60m apart on the same horizontal level ,on the back of the picture .Find the tension in the string if the string is (a) 1.0 m

asked by soumya on September 19, 2017
35. ## music

can you give me words that correspond to the count of a half-note and words that correspond to the count of a quarter note? half note (two beats) "one and, two and" quarter note (one beat) "one, two, three, four" Quarter Note: Sit, Pat, Lit Half Note:

asked by nan on July 20, 2005
36. ## managerial economics

When McDonald's Corp. reduced the price of its Big Mac by 75% if customers also purchased french fries and a soft drink, The Wall Street Journal reported that the company was hoping the novel promotion would revive its US sales growth. It didn't. Within

asked by jean on March 14, 2008
37. ## managerial economics

When McDonald's Corp. reduced the price of its Big Mac by 75% if customers also purchased french fries and a soft drink, The Wall Street Journal reported that the company was hoping the novel promotion would revive its US sales growth. It didn't. Within

asked by jean on March 14, 2008
38. ## Math

The AC voltage coming out of a standard wall plug in the United States can be expressed as the function V(t) = 120sin(120*pi*t), where t represents time (in seconds) and V is the voltage. We will let t be greater than or equal to 0 for simplicity. A. Make

asked by Natalie on May 6, 2013
39. ## Physics

A very narrow beam of white light is incident at 47.50° onto the top surface of a rectangular block of flint glass 13.6 cm thick. The indices of refraction of the glass for red and violet light are 1.649 and 1.678, respectively. 1. Calculate dispersion

asked by Sarah on January 22, 2010
40. ## world history

How was the Song dynasty able to continue its prosperity despite threats from the north? A. More productive farming created a surplus of food, which could be sold. B. The government’s issuance of paper money created more wealth. C. Technological

asked by @realBlueface on January 23, 2019
41. ## world history 9

How was the Song dynasty able to continue its prosperity despite threats from the north? A. More productive farming created a surplus of food, which could be sold. B. The government’s issuance of paper money created more wealth. C. Technological

asked by Blueface on January 23, 2019
42. ## physic

A 1250 kg wrecking ball is lifted to a height of 12.7 m above its resting point. When the wrecking ball is released, it swings toward an abandoned building and makes an indentation of 43.7 cm in the wall. a. What is the potential energy of the wrecking

asked by wellington on December 18, 2014
43. ## physics

a spring lies on a horizontal table, and the left end of the spring is attached to the wall. the other is connected to a box. the box is pulled to the right, stretching the spring static friction exists between the table and the box

asked by Anonymous on October 23, 2014
44. ## math

meredith wants to paint 3 of the walls in her room each wall has the shape of a rectangle with dimensions 10 feet by 12 feet she has 1 can of paint that will cover approixmately 420 square feet which method can meredith use to determine whether or not she

asked by sam on September 12, 2017
45. ## United states history

What similarities do you see between the United States today and the United States of the past? What issues and problems do we continue to grapple with? What successes do we share with Americans in the past? I want to find something now in united states

asked by Selena on December 8, 2014
46. ## statistical analysis

According to the “January theory,” if the stock market is up for the month of January, it will be up for the year. If it is down in January, it will be down for the year. According to an article in the Wall Street Journal, this theory held for 29 out

asked by Anna on August 1, 2013
47. ## calculus

a farmer wants to make a rectangular pen from 200 feet of fencing. he plans to use a 100 foot wall along with some of the fencing to make one side of the pen. find the dimensions of the pen that will make the enclosed area as large as possible.

asked by tina on December 8, 2013
48. ## Grammar

Indentify each sentence below with Simple, compound, complex, or compound-complex. Could you pleas tell me if these are correct? 1.After they defeated Germany in World War II, the Allies divided Germany and its capital city, Berlin, into four sectors: a

asked by HELP NOW on November 29, 2008
49. ## Chemistry

Calculate the sodium ion concentration when 70 ml of 3.M sodium carbonate is added to 30 ml of 1.M sodium bicarbonate.

asked by jess on April 26, 2011
50. ## Chemistry

A 112 mL solution of 0.351 M HCl is added to 52.0 mL of 0.161 M HCl. What is the new concentration of HCl?

51. ## chemistry

Calculate the sodium ion concentration when 72.5 mL of 4.4 M sodium carbonate is added to 32.6 mL of 2.5 M sodium bicarbonate.

asked by justin on October 27, 2010
52. ## chemistry

Calculate the sodium ion concentration when 55.0 mL of 4.5 M sodium carbonate is added to 15.0 mL of 3.0 M sodium bicarbonate.

asked by bob on May 4, 2010
53. ## chemistry

For the equilibrium: H2 + I2 2HI The equilibrium konstant Kc is equal to 50.5 at 448ºC. If [H2]o=[I2] o= 1 mol/l. What will the concentration of H2, I2 and HI be at equilibrium

asked by vicky on November 4, 2016
54. ## chemistry

Calculate the sodium ion concentration when 71.8 mL of 3.2 M sodium carbonate is added to 33.6 mL of 3.7 M sodium bicarbonate.

asked by Anonymous on October 18, 2013
55. ## ap chemistry

The ionization constant of HF is 7.2 × 10−4. What is the molar concentration of H+ in a solution which is 0.353 molar in HF and 0.145 molar in KF?

asked by gabriella on February 4, 2014
56. ## Physics

A man driving his car into 20.0 ft garage with a velocity of 20.0mi/h applies the brakes, producing a constant deceleration. Find the smallest deceleration necessary to avoid striking the back wall of the garage. And find how many seconds it takes for the

asked by Jish on February 23, 2014
57. ## Physics

A man driving his car into 20.0 ft garage with a velocity of 20.0mi/h applies the brakes, producing a constant deceleration. Find the smallest deceleration necessary to avoid striking the back wall of the garage. And find how many seconds it takes for the

asked by Jish on February 22, 2014
58. ## Physics

A boy kicks a soccer ball directly at a wall 41.8 m away. The ball leaves the ground at 42.7 m/s with an angle of 33.0 degrees to the ground. What height will the ball strike the ground? distance = 41.8 m theta = 33.0 degrees Vi = 42.7 m/s

asked by Jasmine Smith on November 24, 2011
59. ## History

Which view of the Establishment Clause would allow greater interplay between government and religion? A. conscientious theory B.accommodationist view C.separationist view D.high-wall theory can any body help me i think its A. conscientious theory but not

asked by Alice on July 31, 2015
60. ## PHYSICS

An object with a mass of 14kg lies on a frictionless incline. A rope attached to the mass runs parallel to the incline and is connected to a wall at the top of the incline. If the rope is considered to be in static equilibrium what is the tension of the

asked by MOLLY on October 13, 2012
61. ## bio

so the question is : List three different factors which influence the rate of enzyme activity and specifically explain each factor’s influence on enzyme activity. My answer: Since enzymes are proteins, they are very sensitive to environmental conditions.

asked by bobs on June 29, 2006
62. ## physics

A bat flying in a cave emits a sound and receives its echo 0.5 s later. How far away is the cave wall? I answered this below. If you cant find it, search on bat flying in the search window above.

asked by Barry on November 5, 2006
63. ## math

Mr.savage used 3 gallons of paint to cover 1350 of square feet of wall .at this rate how much paint wiil be needed to cover 1800 square feet.

asked by sharya on January 3, 2017
64. ## physics

A boy is blowing a whistle of frequency 536 Hz and walking toward a wall with a speed of 1.64 m/s. What frequency of the reflected sound will the boy hear if the speed of sound is 343 m/s?

asked by Jon on April 7, 2008
65. ## Chemistry

I am using 85% ACS grade phosphoric acid. I need to make a 21% phosphoric acid solution with a total volume of 250ml. I have been told that 37ml of the 85% ACS grade phosphoric acid plus 188ml of Deionized water will create the 21% phosphoric acid solution

asked by Melissa on December 9, 2016
66. ## science

If you throw an egg against a wall, the egg will break. But if you throw it at the same speed into a sagging sheer, it may not break. Why?

asked by Emma on October 21, 2007
67. ## Communication Studies

What is the cultural meaning behind an image of a sign of "WALL STREET" ? What would a “semiologist” say about the cultural meaning of an image like this?

asked by Jacinta on July 17, 2009
68. ## Hayden

Choose the pair of words that have a relationship similar to the first pair. 1. accelerate:quicken a. mention:draw b. repair:fix c. stretch:impress d. eat:sleep 2. chassis:car a. alumnus:alumna b. plants:cacti c. flutes:horn d. skelton:body 3.

asked by English on April 24, 2019
69. ## Honors Biology - URGENT!!!

Remember that the greater the concentration of hydrogen ions, the lower the pH of a solution. How do you suppose the pH of the solution in the thylakoid space compares with the pH of the solution in the stroma? What is responsible for the difference?

asked by Brenda on December 8, 2010
70. ## Honor Biology

Remember that the greater the concentration of hydrogen ions, the lower the pH of a solution. How do you suppose the pH of the solution in the thylakoid space compares with the pH of the solution in the stroma? What is responsible for the difference?

asked by Pam on December 6, 2010
71. ## Algebra 2

The pH of a liquid is a measure of how acidic or basic it is. The concentration of hydrogen ions in a liquid is labeled [H+]. Use the formula pH = –log[H+] to find the pH level, to the nearest tenth, of a liquid with [H+] about 5.4 x 10–14. A. 14.7 B.

asked by Tori on December 14, 2012

The pH of a liquid is a measure of how acidic or basic it is. The concentration of hydrogen ions in a liquid is labeled [H+]. Use the formula pH = –log[H+] to find the pH level, to the nearest tenth, of a liquid with [H+] about 5.4 x 10–14. A. 14.7 B.

asked by Tori on December 14, 2012
73. ## Math

Pharmacy has 325mL of a 40% solution. 120mL of sterile water is added to this solution to decrease the concentration. How many grams of active ingredient would be in the diluted solution?(just need to know how to set this up please)

asked by Rayne on September 27, 2015
74. ## Chemistry

0.500 moles of NOCl is placed in a 1.00L vessel at 700K,and after the system comes to equilibrium,the concentration of the NOCl is .440M. Calculate the value of Kc for the reaction @NOCl(g)->2NO(g)+Cl2(g)?

asked by Bob on December 6, 2010
75. ## Physics

Blood flows through a section of a horizontal artery that is partially blocked by a deposit along the artery wall. As a hemoglobin molecule moves from the narrow region into the wider region, its speed changes from v2 = 0.800 m/s to v1 = 0.422 m/s. What is

asked by Hannah on June 20, 2012
76. ## Chemistry

What would be the final concentration if 175mL of a 0.45M solution of sodium sulfite Na2SO3 are added to 650mL of water? Please reply with the steps on how to do this question so I can learn. I can't find examples or anything related in my textbooks and I

asked by bri on June 14, 2012
77. ## College Chemisty

The pH of water collected in a stormwater run-off downstream from a Union Carbide chemical factory is 4.82. Calculate the H+ ion concentration of rainwater. The problem may start with: pH= -log H+ = 4.82. The answer is 1.5x10 power -5. Again, Can you

asked by Elleni on October 22, 2010
78. ## chemistry

20.00 ml of 0.100F Pb(No3)2 (FW 331.2) are mixed with 15.00 ml of 0.125 F Nal (FW 149.9). Lead (II) and iodide form an insoluble salt pbl2 (FW 461.0) Calculate the concentration of each of the remaining ions after mixing. [Pb+2], [i-],[na+],[n03-]. ksp

asked by amrit paul on September 15, 2012
79. ## Engineering

At 300 K we see the electron concentration in the conduction band for pure (undoped) Si is 1010/cm3. How many electrons per Si atom is this? You can use scientific notation, as in A.AAeB Si is diamond cubic with 8 Si atoms per unit cell and a lattice

asked by Solar Solar Cells, Fuel Cells and Batteries on November 1, 2013
80. ## analytical chemistry

A 10.00 mL aliquot of a solution of a weak acid , HA, whose pK a is 4.76 is titrated with OH - generated by electrolysis of water according to th e following scheme: 2 H 2 O + 2 e - â‡” 2 OH - + H 2 (a) [5 points] If the end point in the titration is

asked by jody on May 4, 2013
81. ## Calculus

A ballast is dropped from a stationary hotair balloon that is hovering at an altitude of 500 ft. The velocity of the ballast after t sec is -32t ft/sec. a) Find the height h(t) of the ballast from the ground at time t. Hint: h'(t) = -32t and h(0) = 500.

asked by Debra on December 1, 2016
82. ## Science

When the air under the envelope is heated, the balloon lifts, Which of the following statements is true? A. Hot air balloons use radiation to rise B. Hot air balloons use conduction to rise C. Hot air balloons use convection to rise** D. Hot air balloons

asked by Alice. C on January 6, 2019
83. ## science

when that air under the envelope is heated , the balloon lifts . which of the following statement is true A. hot air balloons use radiation to rise B. hot air balloons use conduction to rise C. hot air balloons use convection to rise D. hot air balloons

84. ## chemistry stoichiometry

My chem teacher gave us this problem Twelve-gauge copper wire,like the kind commonly used in residential electrical systems, is roughly cylindrical and has a diameter of approximately .1040in. Copper's density is 8.92g/cubic cm and copper atoms have an

asked by Julissa on September 9, 2007
85. ## College Chemistry

Calculate the unknown of Ag+ if the potential of the following concentration cell is 300 mV at 25.0 C. Ag|Ag+(unknown)||Ag+(0.100M)|Ag I think I have to use Nernst Equation of Ecell=E0-.0592/nlogQ And at 25C is at 298K so i don't have to change anything. I

asked by Samantha on May 6, 2015
86. ## physics

Glycerin in water diffuses along a horizontal column that has a cross-sectional area of 2.3cm^2. The concentration gradient is 0.028 kg/m^4, and the diffusion rate is found to be 5.8 x 10 ^-15 kg/s find the diffusion coefficient in units of m^2/s.

asked by Ashleigh on November 1, 2010
87. ## Chemistry

3HClO2(aq) +2Cr3+(aq) + 4H2O(l) -> 3HClO(aq) + (Cr2O7)2–(aq) + 8H+(aq) At pH 0.00, with [Cr2O72–] = 0.80 M, [HClO2] = 0.15 M, and [HClO] = 0.20 M, the cell voltage is found to be 0.15 V. Calculate the concentration of [Cr3+] in the cell Ecell = 0.31

asked by RZeal on June 10, 2012
88. ## Chemistry

A voltaic cell consists of Ag/Ag+2 electrode E= 0.80 and a Fe+2/Fe+3 electrode E=0.77 with the following initial molar concentrations: [Fe+2}= 0.30 M [Fe+3]= 0.10 M [Ag+]=0.30 M. What is the equilibrium concentration of Fe+3? (Assume the anode and the

asked by Jackie on July 20, 2012
89. ## physics

I have 2 fill in the blanks that I need help with. 1) When electrons are forced away from a/an ___ plate, work is done. could the answer be positive? 2) Any pointed or angular surface of an object must have a/an ___ concentration of charge to establish

asked by Kriti on April 10, 2011
90. ## Chemistry

1. Chemists define pH as "the negative logarithm of the concentration of protons". In mathematical terms: pH = - log [H+] What is the pH of a solution whose [H+] is 0.0007 M? i got it as 7.0 i know it is wrong 2. What is the [H+] in a solution having a pOH

asked by Lynn on April 30, 2013
91. ## chemistry

Calculate the concentration of all species in a 0.130M solution of H2CO3 Enter your answers numerically separated by commas. Express your answer using two significant figures. [H2CO3], [HCO?3], [CO2?3], [H3O+], [OH?] =

asked by kales on May 6, 2015
92. ## Chemistry

This problem is 1st order for half life. How long would it take for the concentration of cyclopropane to decrease to 50% of its initial value? to 25% of its initial value? Rate constant is 9.2/s I set up like this... t1/2= 0.693/9.2/s= 0.075s at 50% I

asked by Chris on January 21, 2013
93. ## Chemistry

Assuming that seawater has a total ion concentration (aka colligative molarity) of 1.10 M conc, calculate how many liters of seawater are needed to produce 68.7 L of fresh water at 20 C with an applied pressure of 51.0 bar.

asked by Michael Stoll on January 11, 2014
94. ## chemistry

A 0.140-mole quantity of CoCl2 is added to a liter of 1.20 M NH3 solution. What is the concentration of Co2+ ions at equilibrium? Assume the formation constant of Co(NH3)6^2+ is 5.0e31. Please help, I don't know how to do this problem.

asked by Anonymous on May 6, 2012
95. ## Chemistry

The rate constants for a first order decay reaction are found to be: k287.3∘C=1 x 10−4 s−1 k327.4∘C=19.2 x 10−4 s−1 (a) Determine the value, in s-1 of k250∘C (b) How long will it take, at 350 ∘C, for the reactant to decay to 1% of its

asked by selly on January 11, 2013
96. ## Chemistry

The rate constants for a first order decay reaction are found to be: K287.3C = 1 X 10-4s-1 K327.4C = 19.2 X 10-4s-1 (a) Determine the value, in s-1 of K250C (b) How long will it take, at 350C, for the reactant to decay to 1% of its original concentration?

asked by Chemgam on January 11, 2013
97. ## chemistry

The rate constants for a first order decay reaction are found to be: k287.3∘C=1 x 10−4 s−1 k327.4∘C=19.2 x 10−4 s−1 a) Determine the value, in s-1 of k250∘C (b) How long will it take, at 350 ∘C, for the reactant to decay to 1% of its

asked by Anonymous on January 11, 2013
98. ## Chemistry

I have 3 Questions: We actually did the lab experiment for this, but I have no idea whether my reasons are correct. 1) For the equilibrium system Fe+3 + SCN- FeSCN+2, what would happen if you add 2 drops of Fe No3?. Which way will the equilibrium shift

asked by nate Leung on January 30, 2009
99. ## NU

The end of a thin glass-wall tube with an inside diameter of 1-mm is inserted into a reservoir of pure water with a temperature of 25 degree C. What is the surface tension (adhesoin) force on the water inside the tube? To what height will the water rise in

asked by LaToya on March 17, 2011
100. ## Chemistry 106

What are the elements used to make the ingrediants of each category (the same element may be listed in several categories, but a maximum of once in each of the 6 categories, no matter how many different ingrediants it may be in)? **name of the element with

asked by samantha on October 26, 2010