Wednesday
February 10, 2016

# Posts by Emma

Total # Posts: 1,483

Chemistry
NH4NO3 is frequently used as a fertilizer and in explosive compounds dlta Hf values of this compound nd H20 are -365kJmol-1 and -286kJmol-1 respectively. Calculate the amount of heat released bye the dissociation of 1mol of NH4NO3 according to the following reaction 2NH4NO3--&...
February 21, 2013

Chemistry
20cm3 of 0.500moldm-3 H2SO4 was consumed to neutralize 50cm3 of 0.400moldm-3 NaOH. The temperature of the system is increased by 36 degree C. The heat capacity of the calorie meter was 39 JK-1, and the heat capacityof the solution is 4.2JK-1. Find the enthalpy of ...
February 21, 2013

Chemistry
20cm3 of 0.500moldm-3 H2SO4 was consumed to neutralize 50cm3 of 0.400moldm-3 NaOH. The temperature of the system is increased by 36 degree C. The heat capacity of the calorie meter was 39 JK-1, and the heat capacityof the solution is 4.2JK-1. Find the enthalpy of ...
February 21, 2013

Chemistry
20cm3 of 0.500moldm-3 H2SO4 was consumed to neutralize 50cm3 of 0.400moldm-3 NaOH. The temperature of the system is increased by 36 degree C. The heat capacity of the calorie meter was 39 JK-1, and the heat capacity of the solution is 4.2JK-1. Find the enthalpy of ...
February 21, 2013

physics
Cliﬀ divers at Acapulco jump into the sea from a cliﬀ 37.1 m high. At the level of the sea, a rock sticks out a horizontal distance of13.39 m. The acceleration of gravity is 9.8 m/s^2. With what minimum horizontal velocity must the cliﬀ divers leave the ...
February 19, 2013

physics
Bill kicks a rock oﬀ the top of his apartment building. It strikes a window across the street 12 m away. The acceleration of gravity is 9.8 m/s^2. If the window is 16 m below the position where Bill contacted the rock, how long was it in the air?
February 19, 2013

Mathhhhhh!!!!!!!!!!!!!!!!!
OMG please help me .-. (Advanced) Give the domain and range of the relation. x y 2 5 8 17 0 0 –3 –5 Answer a. D: {2, 8, –3, 5, 17, –5}; R: {0} b. D: {–3, 0, 2, 8}; R: {–5, 0, 5, 17} c. D: {–3, 2, 8}; R: {–5, 5, 17} d. D: {–5, 0, 5, ...
February 13, 2013

math
I need help please >(Advanced) Give the domain and range of the relation. x y 2 5 8 17 0 0 –3 –5 Answer a. D: {2, 8, –3, 5, 17, –5}; R: {0} b. D: {–3, 0, 2, 8}; R: {–5, 0, 5, 17} c. D: {–3, 2, 8}; R: {–5, 5, 17} d. D: {–5, 0, 5, ...
February 13, 2013

Chemistry
you would have to use addition. and convert it into a fraction.
February 11, 2013

Chemistry
A solution contains a mixture of pentane and hexane at room temperature. The solution has a vapor pressure of 235 torr. Pure pentane and hexane have vapor pressures of 425 torr and 151 torr, respectively, at room temperature. What is the mole fraction composition of the mixture?
February 11, 2013

English
Is this grammatically correct? "I can't believe that I'm growing up so fast."
February 9, 2013

Math
300 feet
February 6, 2013

Algebra
Simplify : ((-5xy)^2)^5 I got 9765625x^10y^10 I don't that is correct..
February 6, 2013

Physics
Small spheres of diameter 1.00mm fall through 20 degree Celsius water at a terminal speed of 1.10 cm/s. calculate the density of the spheres.
January 31, 2013

History
"They [Jackson and his supporters] see nothing wrong in the rule that to the victor belong the spoils of the enemy." -William Learned Marcy of the U.S. Senate What did Marcy mean by the "spoils of the enemy"?
January 31, 2013

History
Fill in the blank. By the 1850s, railroads were beginning to ___________ canals for transporting goods.
January 27, 2013

History
Fill in the blanks. Under the Mississippi compromise, any new states formed west of the Mississippi river and north of the Missouri's southern border line were required to be __________.
January 26, 2013

History
What cause did Webster support throughout his political career?
January 23, 2013

Math 8 - help!
First use y2-y1/x2-x1 -2-6/-1-1 -8/-2 m= 4 use (1,6) m=4 to substitute into the variables y=mx+b 6=4(1)+b 6=4+b 2=b write your equation y=mx+b y=4x+2
January 23, 2013

Chemistry
Thyroxine, an important hormone that controls the rate of metabolism in the body can be isolated from the thyroid gland. If 0.455 g of thyroxine is dissolved in 10.0 g of benzene, the freezing point of the solution could be measured as 5.144°C. Pure benzene freezes at 5....
January 21, 2013

Math
A large factory knows that if it sells it's new gadgets for \$10 each, it can sell 350 per month and if it sells the same gadgets for \$8 it will sell 500 per month assuming the relationship between price and sales is linear predict the monthly sales of gadgets to the ...
January 17, 2013

Math
Use a calculator to simplify the expression. 8/2^3-2+4.1*2 When I used the calculator, I got 22.2 So then I used "PEMDAS" but got 7.53333... But the answer is 7.2 can someone help please?
January 17, 2013

Earth Science
1. What are one internal and one external source of energy in the Earth system? 2. Earth scientists assume that the causes of natural events of phenomena can be discovered through... 3. Science constantly creates new technology. Does this new technology always benefit society?
January 13, 2013

MATH!!!
Fist you use the distributive property method. 3(d+12)=8-4d 3d+36=8-4d Subtract 8 from each side 3d+28=-4d Subtract 3d from both sides 28=-7d divide by -7 from each side ?= d
January 13, 2013

math
how much money do i have left from 36p if i spend 1/4 of it
January 13, 2013

English
This sentence has an error but I'm not sure if this is correct. His father and uncle were theirselves great travelers. Is it suppose to be: His father and uncle were themselves great travelers.
January 12, 2013

Earth Science
A. Water
January 12, 2013

Earth science
B. Pressure
January 12, 2013

Math
i don't under stand the word math problem
January 12, 2013

Earth science
Plate tectonics
January 12, 2013

MATH
First, you combine like-terms. 11w-9-7w=15 11w minus 7w is 4w 4w-9=15 add 9 to each side 4w=24 divide each side by 4 w= ?
January 12, 2013

Earth Science
1. What are one internal and one external source of energy in the Earth system? 2. Earth scientists assume that the causes of natural events of phenomena can be discovered through... 3. Science constantly creates new technology. Does this new technology always benefit society?
January 12, 2013

MATH HELP!!!!!!
First, you subtract 4 from both sides, then times 7/2 on each side: 10 = 2/7n+4 14= 2/7n 49=n
January 12, 2013

English
Choose the pronoun that correctly completes each sentence. 1. (who, whom) will the choir director choose? Is it whom?
January 10, 2013

Algebra
A store is selling compact discs for \$10.50 and \$8.50. You buy 10 discs and spend a total of \$93. How many compact discs did you buy for \$10.50? \$8.50?
January 9, 2013

Algebra
The girl's basketball team scored 57 points and made 25 shots. Each shot was worth 2 or 3 points each. Write a linear system.
January 9, 2013

A farmer is tracking two wild honey bees in his field. He maps the first bee's path back to the hive on the line y=9/7x. the second bee's bee path follows the line y=-3x+12. Their paths cross at the hive. At what coordinate will the farmer find the hive? I got (-6/7, 6)
January 7, 2013

Trigonometry
Yes I had a typo. Thank you!! (I don't know how to respond to answers besides this....)
January 7, 2013

Trigonometry
Prove that tanx+cotx=2sec(2x) Thank you! :)
January 7, 2013

Algebra
Use the substitution method to solve the linear system. 1/8p+3/4q=7 3/2p-q=4 Thanks.
January 6, 2013

Algebra
Use substitution method to solve the linear system. Can someone please check if I did this problem right? Thanks X+y=12 X+3/2y=3/2 Y=21 x=-9
January 6, 2013

algebra
I have another question. So I solved the problem but then I have to put it in an ordered pair form. If I was using the variables "x and y," then it would be (x,y) but what if I were using different variables, in this case s and t, how do I know which one is the x and...
January 6, 2013

algebra
Use the substitution method to solve the linear system. Thanks! s= t+4 2t+s=19
January 6, 2013

trig
2sinxcosx+4sin^2xcos^2x=0 solve for x in radians between [0,2pi) (I mean that it is sine squared x and cosine squared x not sine to the power of 2x or cosine to the power of 2x)
December 19, 2012

Math
When the mean is greater than the median, what does it suggests about the data set?
December 17, 2012

English
Find the plural that has been formed incorrectly. Then write it in its correct plural form. Dad was hoping to catch several bass and trouts for our suppers. I'm not sure if it's "trouts" or "suppers".
December 13, 2012

math
andrea cuts 62 1/2 inches of ribbon into 4 equal hair ribbons. How long was each hair ribbon?
December 12, 2012

Algebra
I don't get how you would know which way to shade the inequality when it's true or false. For example the inequality 2x+3y> 12 When I solve it it's y>-2/3x+4 But when I graph the line how would I know which side to shade?
December 12, 2012

Language
Hi! So I am having a hard time in Chinese class. Paying Attention that is. My teacher lets all the students goof off, and it's hard to pay attention. She doesn't care if we are on our phones, so it's a BIG temptation. I know that if I payed attention in class more...
December 11, 2012

Algebra
I solved the inequality and now I have to graph and shade it in. Y<-5x-6 0<-5x-6 I used the test point 0,0 and substituted in y but how do I know if it's true or false?
December 11, 2012

Algebra
Solve the inequality and graph. 7<1-x<13 I got -6 >x >-12 Is that correct?
December 9, 2012

English
Identify the nouns and verb/verb phrases in the sentence. Employers value honesty and hard work. Nouns: Employers, honesty, and work Verb: Value
December 9, 2012

Chemistry
The titration of 25.0 mL of an unknown concentration H2SO4 solution requires 83.6 mL of 0.12 M LiOH solution. What is the concentration of the H2SO4 solution (in M)?
December 6, 2012

Chemistry
The temperature rises from 25.00 °C to 29.00 °C in a bomb calorimeter when 3.50 g of sucrose undergoes combustion in a bomb calorimeter. Calculate ÄErxn for the combustion of sucrose in kJ/mol sucrose. The heat capacity of the calorimeter is 4.90 kJ/°C . The ...
December 6, 2012

Chemistry
How many atoms of carbon are contained in 47.6 g of Al2(CO3)3? The molar mass of Al2(CO3)3 is 233.99 g/mol.
December 6, 2012

chemistry
Choose the bidentate ligand from the substances below. A) cyanide ion B) ammonia C) EDTA D) carbon monoxide E) ethylenediamine
December 6, 2012

Chemistry
The complex ion, [Ni(NH3)6]2+, has a maximum absorption near 580 nm. Calculate the crystal field splitting energy (in kJ/mol) for this ion.
December 6, 2012

Chemistry
Which of the following compounds can exhibit cis-trans isomerism? A) [Fe(CO)5ONO]2+ B) [Fe(CO)3(NH3)3]3+ C) [Cu(CO)5Br]+ D) [Cr(H2O)4Br2]+ E) [Fe(NH3)6]2+
December 6, 2012

Chemistry
Determine the volume of H2S (at 375 K and 1.20 atm) needed to produce 55.0 g of S. Assume that there is excess SO2 present. 2 H2S(g) + SO2(g) ¨ 3 S(s) + 2 H2O(g)
December 6, 2012

Chemistry
What element is undergoing oxidation (if any) in the following reaction? CH4(g) + 2 O2(g) ¨ CO2(g) + 2 H2O(g)
December 6, 2012

Chemistry
combustion analysis of 63.8 mg of C,H, and O containing compound produced 145.0 mg of CO2 and 59.38 mg of H2O. What is the empirical formula for the compound?
December 6, 2012

RE:ENGLISH QUOTE
Is there a different way to explain the meaning of the quote?
December 2, 2012

RE:ENGLISH QUOTE
Here is my meaning of Hellen Keller's quote: It means that by using my voice I can do something. I may not be THE one but AT LEAST I AM one. I know that I can't do everything but the thing is, I CAN do SOMETHING. I will do what I can do to make a difference. I don'...
December 2, 2012

English
“I am only one, but still I am one. I cannot do everything, but still I can do something; and because I cannot do everything, I will not refuse to do something that I can do.” Please explain what this quote means, thanks!
December 2, 2012

English
"It is better to lead from behind and to put others in front, especially when you celebrate victory when nice things occur. You take the front line when there is danger. Then people will appreciate your leadership." What does this quote mean?
December 2, 2012

English-Speech
I am workng on my introduction part of my speech and here is my transition sentence: With my voice, I can make a difference in 5 different ways. Would these be like the examples of the "5 different ways" ? preventing people from doing a bad action, helping a friend ...
December 1, 2012

English
What does the quote, ""The world is not interested in what we do for a living. What they are interested in is what we have to offer freely - hope, strength, love and the power to make a difference!" mean?
November 30, 2012

math
You need 1/2 cup of sugar to make a three layer cake. How much sugar would you need for one-layer cake?
November 29, 2012

math
2/10 , 3/15 , 4/20, 5/25 Those are some examples.
November 27, 2012

English
I want to put these words in a sentence that makes sense. Many will think that my voice doesn't matter for people my age. It doesn't sound right to me.
November 27, 2012

Physics
three rotating, uniform disks that are coupled by belts. One belt runs around the rims of disks A and C. Another belt runs around a central hub on disk A and the rim of disk B. The belts move smoothly without slippage on the rims and hub. Disk A has radius R; its hub has ...
November 27, 2012

English
What would be a good quote to describe me encouraging someone to become a better singer? How about giving advice and preventing something?
November 25, 2012

math
You are correct.
November 25, 2012

math
4x if x=0.016 You just substitute in 0.016 for x 4 * 0.016 = ?
November 25, 2012

English Speech
That does not make any sense to me...
November 25, 2012

English Speech
This year, all the students in the same grade has to give a speech and the topic is "My voice is important because..." instead of repeating in every new story, "my voice is important because.." what is another way to state it?
November 25, 2012

physics
The small mass m sliding without friction along a looped track is to remain on the track at all times, even at the very top of the loop of radius r. a) In terms of the given quantities, determine the minimum release height h b) If the actual release height is 5h, calculate the...
November 24, 2012

chemistry
Aspirin tablet, mass of tablet= 0.4149 g concentration of iron III salicylate complex = 3.997E-4, What is the concentration of ASA in the original solution? What is the mass of ASA in the original solution? The procedure was as follows: accurately weigh by difference a tablet ...
November 20, 2012

chemistry
Aspirin tablet, mass of tablet= 0.4149 g concentration of iron III salicylate complex = 3.997E-4, What is the concentration of ASA in the original solution? What is the mass of ASA in the original solution? The procedure was as follows: accurately weigh by difference a tablet ...
November 20, 2012

Chemistry
Aspirin tablet, mass of tablet= 0.4149 g concentration of iron III salicylate complex = 3.997E-4, What is the concentration of ASA in the original solution? What is the mass of ASA in the original solution? The procedure was as follows: accurately weigh by difference a tablet ...
November 20, 2012

Chemistry
So does that mean that the salicylate and the iron 3 complex will have an equal amount of mol since they are reacting in a 1:1 mol ratio. If this is true than how will i calculate the concentration of the iron 3 salicylate complex?
November 19, 2012

Chemistry
1 ml of 8.675x10^-3 M sodium salicylate was dispensed in a 100 ml volumetric flask, It was diluted to 100ml mark with acidified 0.02 M Iron (III) Chloride solution. What is the number of moles of Iron (III) Salicylate complex?
November 19, 2012

History
What are five kinds of cases heard by the Federal Courts?
November 19, 2012

History
Thanks! It really helped a lot. I don't think I need help on the question that I posted anymore.
November 19, 2012

History
What are the four powers denied to congress?
November 19, 2012

chemistry
Spectrophotometric analysis of commercial aspririn. If the number of moles of sodium salicylate are 8.675x10^-6 what would be the number of moles of Iron (III) Salicylate complex and what would be its concentration. The volume of sodium salicylate used is 1 ml and its ...
November 19, 2012

physics, university
A 50.0-g sample of a conducting material is all that is available. The resistivity of the material is measured to be 11 x 10-8 ohms/m and the density is 7.86 g/cm3. The material is to be shaped into a solid cylindrical wire that has a total resistance of 1.5 ohms. a) What ...
November 19, 2012

Math
14.8cos(27.8)(29cos(x))+14.8sin(27.8)(29sin(x))=22 How do you solve for x?
November 17, 2012

Physics
Vectors A and B are in the xy plane and their scalar product is 20.6 units.? If A makes a 27.8 angle with the x axis and has magnitude A= 14.8 units, and B has magnitude B= 29.0 units, what can you say about the direction of B?
November 17, 2012

Did I do this problem right? Rewrite the equation in slope-intercept form. y+4=5(x+2) y=5x+6
November 15, 2012

physics
The maximum possible efficiency of a heat engine which exhaust its heat at a temperature of 46.0o is 39.0 percent. What is the minimum value of the temperature at which the engine takes in heat? *I think I keep doing a step wrong in here so step by step instruction would be so...
November 15, 2012

PHYSICS
15.0 moles of an ideal gas, at an initial pressure of 3.50 x105 N/m2 and an initial volume of 1.200 m3, undergo a small isothermal expansion to a volume of 1.220 m3. Find the work done by the gas.
November 14, 2012

English
Are there any words that end with "ale" or "ail" that is a place?
November 14, 2012

Chemistry
Thankyou Dr. Bob also on my other question I am not sure how to get the heat capacity of NH4Cl to calculate molar enthalpy and I also don't know how to determine the concentration of NH4Cl inside the calorimeter. Please help me on that question as well and thankyou soo much.
November 13, 2012

Chemistry
A 5ml, 10ml, 15 ml, and 20ml Aliquot of 0.010 M sodium salicylate solution was diluted to 100 ml in four different 100ml volumetric flasks with the iron (III)Chloride solution. What are their concentrations.
November 13, 2012

Chemistry
Thankyou Dr. Bob and can you please help me on one more question if this reaction goes to completion what would the final concentration of NH4Cl in the calorimeter. I know how to figure it out if its not in the calorimeter but I am wondering if the calculations are different ...
November 12, 2012

Chemistry
I don't know the heat capacity of NH4Cl or the density of it, can you please help me figure those out.
November 12, 2012

Chemistry
Calculate the molar enthalpy for the following reaction. HCl(aq) + NH3 (aq) --> NH4Cl (aq). HCl = 50 ml (2.00M) NH3 = 50 ml (2.05 M) Delta T = 9.28 degrees Celsius. Ccal = 28.9J/g degrees celcius.
November 12, 2012

Math
Please help me understand this question, thanks! 10. Write the slope-intercept form of an equation of the line perpendicular to the line in Exercise 7 with a y-intercept of -3. 7. (4, -9), (-3, 2)
November 12, 2012

Physics
Three uniform thin rods, each of length L = 16 cm, form an inverted U. The vertical rods each have mass of 14 g; the horizontal rod has mass of 50 g. Where is the center of mass of the assembly (x, y)?
November 12, 2012