Saturday
December 10, 2016

Posts by Patrick

Total # Posts: 726

chemistry
Deterioration of buildings, bridges, and other structures through the rusting of iron costs millions of dollars everyday. Although the actual process also requires water, a simplified equation (with rust shown as iron(III) oxide (Fe2O3) is: 4Fe(s)+3O2(g) --> 2Fe2O3(s) ...
October 13, 2015

chemistry
Dr. Bob.. 630.24 kj was marked wrong...it said hint: make sure to carry out dimensional analysis........ ÄH value refers to the amounts of (moles) of substances and their matter in that specific equation. help....please....
October 13, 2015

chemistry
Consider the following balanced thermochemical equation for a reaction sometimes used for H2S production: 1/8 S8 (s) + H2 (g) ¨ H2S (g) ƒ¢Hrxn = -20.2 kJ (a)Is this an exothermic or endothermic reaction? (b)What is ƒ¢Hrxn for the reverse reaction...
October 13, 2015

chemistry
A 49.3 g sample of ethylene glycol, a car radiator coolant, loses 624. J of heat. What was the initial temperature of ethylene glycol if the final temperature is 32.5°C (c of ethylene glycol = 2.42 J/gK)? 624= 49.3 x 2.42(T-32.50) T = 37.73 = 38degrees is this correct? ...
October 13, 2015

chemistry
What is the (H3O+) and the ph of a buffer that consists of 0.25M HNO2 and 0.69M KNO2? (Ka of HNO2 = 7.1 x 10^-4) is this right? pH of acidic buffer pH = pka + log(salt/acid) pka = -log ka = -log(7.1*10^(-4)) = 3.15 = 3.15+log(0.25/0.69) pH = 2.71 [H3O+] = 10^-pH = 10^(-2.71...
October 9, 2015

Math
2.0
October 8, 2015

Math
A bakery used 4 cups of flour to make a full size cake. If they wanted to make a cake that was 0.5 the size, how many cups of water would they need.
October 8, 2015

Math
I apologize about this question I meant to send a different
October 8, 2015

Math
On Halloween 2 friends received 0.1 of a pound of candy. How much candy did they receive total?
October 8, 2015

math correction
correction what is : 1 x 10^-14 / 2.54 x 10^-3 the x's are (times) not variables thank you.
October 5, 2015

math
what is 1 x 10-14 / 2.54 x 10 -3 the x's are times not variables. I need the answer in scientific notation
October 5, 2015

chemistry
excited state
October 5, 2015

chemistry
The weak acid HQ has pKa of 4.89. Calculate the (OH-) of 0.500 M HQ This is what I have: pKa = 4.89 so Ka = 10^-4.89 = 1.29x10^-5 Ka = 1.29x10^-5 = [H+][Q-] / [HQ] 1.29x10^-5 = x^2 / 0.046 - x x^2 + 1.29x10^-5x - 5.93x10^-7 = 0 x = [H+] = 7.64x10^-4M pH = -log[H+] = 3.12 1....
October 4, 2015

chemistry
The weak acid HQ has pKa of 4.89. 1)Calculate the [H3O+] of .035 M HQ. 2)Calculate the (OH-) of 0.500 M HQ ....Am I correct? a) pKa = 4.89 => - log(Ka) = 4.89 => Ka = antilog(- 4.89) = 10-4.89 = 1.29x10-5 1. Given concentration of HQ, C = 0.035 M Dissociation of HQ is ...
October 4, 2015

ap chemistry
The weak acid HQ has pKa of 4.89. 1)Calculate the [H3O+] of .035 M HQ. 2)Calculate the (OH-) of 0.500 M HQ ....Am I correct? a) pKa = 4.89 => - log(Ka) = 4.89 => Ka = antilog(- 4.89) = 10-4.89 = 1.29x10-5 1. Given concentration of HQ, C = 0.035 M Dissociation of HQ is ...
October 4, 2015

chemistry
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 ...
October 4, 2015

chemistry
How many moles of H3O+ or OH- must you add per liter of HA solution to adjust its pH from 9.75 to 9.01? Assume a negligible volume change. ……….x 10………Moles of ……………………..h3O+ or OH- I got 4.6001 x 10-5 M of ...
October 4, 2015

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 ...
October 4, 2015

chemistry
How many moles of H3O+ or OH- must you add per liter of HA solution to adjust its pH from 9.75 to 9.01? Assume a negligible volume change. ……….x 10………Moles of ……………………..h3O+ or OH- I got 4.6001 x 10-5 M of ...
October 4, 2015

chemistry
Codeine (C18H21NO3) is a narcotic pain reliever that forms a salt with HCl. What is the pH of 0.064 M codeine hydrochloride (pKb of codeine is 5.80)? Thank you.
October 2, 2015

AP Chemistry
I am fairly sure that a) is no change, and c) is shifts to the right...but I am not sure about b) and d). Thanks. How does the equilibrium position shift as a result of each of the following disturbances? Sodium bicarbonate undergoes thermal decomposition according to the ...
October 1, 2015

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=
September 29, 2015

Math
Wtf
September 28, 2015

Chemistry
I was doing a lab experiment on the reaction of copper(II) sulphate and aluminum: 1) I measured 2.02g of copper(II) sulphate pentahydrate 2) I dissolved the copper(II) sulphate pentahydrate in 10mL of distilled water 3) I added 2.0mL of concentrated HCl to the solution and ...
September 26, 2015

Chemistry
I was doing a lab experiment: 1) I measured 2.02g of copper(II) sulphate pentahydrate 2) I dissolved the copper(II) sulphate pentahydrate in 10mL of distilled water 3) I added 2.0mL of concentrated HCl to the solution and mixed well 4) I added 0.25g on Aluminun foil to the ...
September 26, 2015

CBU
I was doing a lab experiment on the reaction of copper(II) sulphate and aluminum: 1) I measured 2.02g of copper(II) sulphate pentahydrate 2) I dissolved the copper(II) sulphate pentahydrate in 10mL of distilled water 3) I added 2.0mL of concentrated HCl to the solution and ...
September 26, 2015

CBU
How to calculate moles in a sample
September 26, 2015

math
Allison and Fred both work at the mall., but Allsion make $2 more than Fred. They work equal hours. Let x represent Allison earnings and y to represent Fred earnngs. Draw a graph representing the relationship between Allison and Fred earnings.
September 21, 2015

Math
combine like terms. 14 + 5x + 15 - 7x 29 - 2x
September 21, 2015

chemistry
Assume water boils at 100.0 C in Houston(near sea level) and at 90.0 C in Cripple Creek Colorado(near 9, 500 feet). If it takes 4.7 min to cook an egg in Cripple Creek and 4.4 min in Houston, what is Ea for this process? Enter your answer in scientific notation. Thanks.
September 14, 2015

chemistry
Assume water boils at 100.0 C in Houston(near sea level) and at 90.0 C in Cripple Creek Colorado(near 9, 500 feet). If it takes 4.7 min to cook an egg in Cripple Creek and 4.4 min in Houston, what is Ea for this process? Enter your answer in scientific notation. Thanks.
September 14, 2015

science
. Three charges are positioned as indicated in the figure. Calculate net force exerted on the +15 µC charge by the +11 µC and +13 µC charges
September 2, 2015

Physics
A 480 N man is standing on a 120 N pole supported by 2 blocks. The pole is 6 m long. One block is at the end while the other is 2 m away from the center. Where should the 480 N man stand?
July 12, 2015

Life orientation
Evaluate the extent to which the service delivery protes of water met or didi not met the rquirements of processes that you have to reseached
May 16, 2015

Communication in the Workplace
an outline for the letter would be nice
April 15, 2015

Communication in the Workplace
Imagine that you have taken a new job as head of Human Relations (HR) for an up-and-coming software firm. Your 150 employees are hip, smart and tech savvy. They are also big cell phone users. Cell phones are an important tool for your business communications, and you don't...
April 15, 2015

physics
Calculate the coefficient of kinetic friction for tyre rubber on the road surface.
April 2, 2015

CDA
I think D
March 21, 2015

English check
I agree with a
March 21, 2015

Physics
Two horizontal forces Upper F1 Baseline and F2 act on a 3.6 kg disk that slides over frictionless ice, on which an xy coordinate system is laid out. Force F1 is in the positive x direction and has a magnitude of 7.1 N. Force F2 has a magnitude of 9.3 N. The figure here gives ...
March 15, 2015

math
write 1.5 billion as a standard numeral
March 10, 2015

religion
"The Will to Believe," contains William James' response to Clifford. You are to write 200-300 words explaining James' response to Clifford's position. Be sure to include the following: 1. Explain James classification of hypotheses as alive or dead and the...
February 26, 2015

Science:Physics
Nilo drives is van with an average velocity of 45.0 km/h along the North Expressway. How long will it take him to drive 350 km on a perfectly straight highway
January 30, 2015

Accounting
Jay Pembroke started a business. During the first month (April 20--), the following transactions occurred. Invested cash in business, $18,428. Bought office supplies for $4,433: $1,896 in cash and $2,537 on account. Paid one-year insurance premium, $1,003. Earned revenues ...
January 22, 2015

statistics
1. On the basis of past experience, the buyer for a large sports store estimates that the number of 10-speed bicycles sole next year will be somewhere between 40 and 90 – with the following distribution: Number of Bicycles Sold x Probability P(x) 40 0.05 50 0.15 60 0.41 ...
January 22, 2015

Science
Why are phosphates rocks useful?
January 14, 2015

physics
how much heat is needed to raise the temperature of 5kg of silver from 20 degrees C to 96 decgrees C?
January 12, 2015

Calculus
An aquarium is to be constructed to hold 2160 in3. The base is to made of slate and the sides of glass. If slate costs 5 times as much as the glass per sq in, find the dimensions that will minimize the cost of constructing the aquarium. I started going about this problem by ...
November 28, 2014

CHEMISTRY
how can different steps in the analytical process help in solving probs in Analytical Chemistry
November 26, 2014

english
All of the following compound nouns are correct except a.editors in chief. b.sons-in-law. c.bird watchers. d.mother-in-laws. I am think a
November 19, 2014

math
Janet bakes a cake in the shape of a cube with side length x (in inches). She makes a vertical cut parallel to one of the sides, resulting in a slice with width y where x is 5 times as large as y. a) Define a function h that determines the volume of the cake before Janet makes...
October 8, 2014

Physics
Initial speed = 28m/s time = 4.4s Acceleration = 9.8 Just plugin the numbers into this formula and u will get the answer. S=ut+1/2*a*t^2
October 8, 2014

CHECK PLEASE
abscond : flee :: A. ascertain : forget B. concise : cut C. discern : hide D. abhor : detest
September 22, 2014

statistics
The mean sleep time of babies is 14hrs,a sample of 64 babies showed a mean of 13hrs 30min with a standard deviation of 3hrs at 1% level of significance. Test the assertion that the mean sleep of the babies is less than 14hrs a day.
August 7, 2014

statistics
The mean lifetime of a sample of 100 light tubes is 1570 hours with a standard deviation of 80 hours test the hypothesis that the mean lifetime of the tubes is 1600 hours
August 7, 2014

Calculus Help Please Urgent!!!
A cone-shaped paper drinking cup is to be made to hold 30 cm^3 of water. Find the height and radius of the cup that will use the smallest amount of paper. (Round your answers to two decimal places.) Height = ? Radius = ? Show work please!!!
April 15, 2014

CHEMISTRY HELP !!!!
the following statement is false. Rewrite that it makes a correct statement about free energy. a. ΔGuniverse > 0 for any spontaneous process.
April 15, 2014

CHEMISTRY HELP !!!! Show work please!
Compute the energy released in kilojoules when the sun converts 1.00 metric ton into energy. NOTE: 1 metric ton = 1000 kg.
April 14, 2014

math
77.5
April 8, 2014

Math (Trigonometry)
1. If sec x + tan x = 3/2 and 0 ≤ x ≤ pi/2 then the value of sin x is... 2. If 0 ≤ x ≤ pi/2 and tan²x + sec x = 5 then cos x = ... Please help
April 6, 2014

Physics
The seesaw in the figure below is 4.5 m long. Its mass of 20 kg is uniformly distributed. The child on the left end has a mass of 14 kg and is a distance of 1.4 m from the pivot point while a second child of mass 39 kg stands a distance L from the pivot point, keeping the ...
March 28, 2014

Statistics
An economist found that a random sample of 42 high school teachers had an average annual salary of $56,490. A previous study showed that the population standard deviation is $4150. Calculate the margin of error, E, for a 99% confidence interval for µ, the average annual ...
March 1, 2014

bergen community college
210cm
November 8, 2013

chemistry
A 47kg sample of water absorbs 3.40×10^2kJ of heat. Part A If the water was initially at 21.5∘C, what is its final temperature?
September 15, 2013

chemistry
Gold has a density of 19.3 g/cm3. Do you think you could carry 1.30 cubic ft (rhetorical--don't answer)? How many pounds does 1.30 cubic feet of gold weigh? [453.6 g = 1 lb, 2.54 cm = 1 in, and 1 ft = 12 in.]
September 14, 2013

Math: Algebra
800
September 10, 2013

Calculus
The equation of motion of a particle is s=4t^3−7t, where s is in meters and t is in seconds. Find a) the velocity of the particle as a function of t : v(t)= b) the acceleration of the particle as a function of t : a(t)= c) the velocity after 5 seconds d) the acceleration...
June 13, 2013

Math
Im thinking of a two-digit number. It is a prime number which is 3 less than a perfect square. Also, when it's digits are reversed, it becomes a perfect square. What is the one possible number?
June 11, 2013

geometry
45. Find the similarity ratio of a cube with a volume 512 m3 to a cube with volume 3,375 m3. (1 point) 8 : 15 64 : 225 15 : 8 225 : 64
June 10, 2013

Geometry
help please
June 10, 2013

Geometry
44. The volume of a sphere is 2,098 m3. What is the surface area of the sphere to the nearest tenth? (1 point) 1,700 m2 146.2 m2 850 m2 26,364 m2
June 10, 2013

us history
Ms. Sue, trying to figur out how to even break down the question? Thanks, Patrick
May 4, 2013

us history
3. Keeping in mind how the expansion of U.S. territory westward threatened the delicate balance of power in Congress between free and slave states and Lincoln’s stance on slavery, describe how key events (such as land acquisitions, agreements about how new territories ...
May 4, 2013

History
2. The new democratic age of the 1820s, ’30s, and ’40s not only witnessed the advent of universal white male suffrage but also a strong impulse for social reform, which was often supported by those denied access to the ballot. What drove the impulse behind such ...
May 4, 2013

maths
When pulled a 30 m piece of string streches 180cm.find percentage increasing length
April 22, 2013

govenment
a, c, and d
March 28, 2013

Chemistry
How do you write a chemical equation for NH4NO3? Is it... NH3 + H2O= NH4 + OH
March 19, 2013

Physics
I am having a problem answering a physics question: A plane is heading due south and climbing at the rate of 60 km/hr. If its airspeed is 540 km/hr and there is a wind blowing 110 km/hr to the northwest, what is the ground speed of the plane?
March 17, 2013

Chemistry
Suppose 50.00 mL of 2.0 E -5 M Fe(NO3)3 is added to 50.00ml of 2.0 E -4M KIO3. Which of the following statements is true? For Fe(IO3)3, Ksp= 1.0 E-14 a-precipate forms because Qc<Ksp b-No precipate forms because Qc>Ksp c-Nothing happended d-No precipate forms because Qc&...
March 17, 2013

Chemistry
I figured out the answer. Thanks.
March 17, 2013

Chemistry
What is the solubility (in g/L) of PbCl2 at 25 degree celsius? The solubility product of PbCl2 at 25 degrees celcius is 1.6x10-5.
March 17, 2013

chemistry
How many electrons in a cesium atom can have the quantum numbers of n = 3 and ml = -1
March 9, 2013

maths help please
9409
February 27, 2013

Chemistry
Question asking about how enzymes affect the rate of a reaction. Check all that apply 1. They shift the reaction equilibrium towards the products. 2. They increase the concentration of the reactants. 3. They lower the activation energy of the reaction. 4. They decrease the ...
February 20, 2013

Physics
Two blocks sit on a horizontal surface. They are connected to each other by a massless cord. The block on the left has a mass of 4.8 kg and the block on the right has a mass of 2.2 kg. Another massless cord is attached to the block on the right and pulls that block with a ...
February 18, 2013

Physics
A thin 5.4-m metal rod sustanins a longitudinal standing wave with vibration antinodes at each end of the rod. There are no other antinodes. The density and Young's modulus of this metal are, respectively, 5200 kg/m^3 and 7.9x10^10 N/m2. What is the frequency of the rod&#...
February 11, 2013

physic
A canon is angled at 45º and fires a canon ball at 100 m/s. How long will it take the canon to reach it's maximum height?
February 4, 2013

physic
A canon is angled at 45º and fires a canon ball at 100 m/s. How long will it take the canon to reach it's maximum height?
February 4, 2013

Chemistry
Which ligand binds the tightest? Ligand A, with a Kd of 10^-9M Ligand B, with a Kd of 10^-3M Ligand C, with a percent occupancy of 30% at one micromolar Ligand D, with a percent occupancy of 80% at 10 nm
January 31, 2013

Chemistry
I'm given sequences and asked to classify them as "Most likely an amphipathic alpha helix", "Most likely an amphipathic beta sheet", "Most likely a turn/loop" or "Not Amphipathic" Sequence 1: Arg-Phe-Gln-Ile-His-Val-Gln-Phe-Glu ...
January 29, 2013

Math
HELP! Input:1 1/3 Output 7/12 Input 2 3/5 Output 1 17/20 Input 3 5/6 Output ? Input ? Output 3 5/8. What is the rule, and what are the question marks values?
January 23, 2013

Physics
A long jumper leaves the ground at an angle of 15.1◦ to the horizontal and at a speed of 10.9 m/s. How far does he jump? The acceleration due to gravity is 9.8 m/s2 . Answer in units of m 010 (part 2 of 2) 10.0 points What maximum height does he reach? Answer in units of m
January 23, 2013

chemistry
23 grams of NaOH is dissolved in 1.5L of water, find; a)Concentration of the solution b)pOH c)pH
January 20, 2013

chemistry
A chemist decomposes several samples of carbon monoxide into carbon and oxygen and weighs the resultant elements. The results are shown below: Sample Mass of Carbon Mass of Oxygen 1 6 8 2 12 16 3 18 24 Do you notice a pattern in these results? Next, the chemist decomposes ...
January 13, 2013

Physics
Find the work done in stretching the spring. Answer in units of J
December 14, 2012

Physics
The force required to stretch a Hooke’s-law spring varies from 0 N to 70.4 N as we stretch the spring by moving one end 5.35 cm from its unstressed position. Find the force constant of the spring. Answer in units of N/m
December 14, 2012

physics
A 22 g bullet is accelerated in a rifle barrel 43.2 cm long to a speed of 907 m/s. Use the work-energy theorem to find the average force exerted on the bullet while it is being accelerated. Answer in units of N
December 14, 2012

math 5th grade
Lynda cut 3.2 meters of ribbon into equal-size pieces. Each piece was longer than .01 meter, but shorter than .02 meters, with lengths in increments of .02 meters. How many pieces did Lynda cut and how long was each piece?
December 12, 2012

Chemistry 12
given the reacting system: H2 (G) + I2(G) ---> 2HI(g) Keq= 64 Equal moles of H2, I2, and HI are placed in a 1.0 L container. Use calculations to determine the direction the reaction will proceed in order to reach equilibirum
December 6, 2012

Chemistry 12
given the reacting system: H2 (G) + I2(G) ---> 2HI(g) Keq= 64 Equal moles of H2, I2, and HI are placed in a 1.0 L container. Use calculations to determine the direction the reaction will proceed in order to reach equilibirum
December 6, 2012

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