Rose Bud
Popular questions and responses by Rose Bud
Chemistry  Enthalpy reactions
What is the reaction enthalpy for CaCO3(s) > CaO(s) + CO2(g)? should i be using a enthalpy reaction table?
asked on February 29, 2012 
chemistryThermochemistry (grade 12)
calculate enthalpy of H for the reaction N2H4(l) + 2H2O(l) > N2(g) + 4H2)(l) Given the reactions N2H4(l) + O2(g) > N2(g) + 2H2O(l) Enthalpy of H = 6.22.2 kJ H2(g) + (1/2)O2(g) > H2O(l) enthalpy of H = 285.8 kJ/mol H2(g) + O2(g) > H2O2(l) enthalpy of
asked on February 16, 2012 
elementary stats
the participants in a television quiz show are picked from a large pool of applicants with approximately equal number of men and women.Among the last 11 participant there have been only 2 women.If participants are picked randomly,what is the probability of
asked on February 23, 2012 
Elementary statistics
Nine apples, four of which are rotten, are in a refrigerator. Three apples are randomly selected without replacement. Let the random variable x represent the number chosen that are rotten. Construct a table describing the probability distribution, then
asked on February 29, 2012 
elementary stats
On a multiple choice test with 11 questions, each question has four possible answers, one of which is correct. For students who guess at all answers, find the mean for the number of correct answers.
asked on February 23, 2012 
Mad percent of CuS and Cu2S in an ore sample
Suppose an ore sample contains 11.01 % impurity in addition to a mixture of Cu2S and CuS. Heating 102.5 g of the mixture produces 74.90 g of solid which is 88.18 % copper. What is the mass percent CuS in the ore?
asked on September 24, 2012 
elementary statistics
The number of calls received by a car towing service averages 21.6 per day (per 24hour period). Find the probability that in a randomly selected hour the number of calls is fewer than 4. What requirement for the Poisson distribution is probably not valid
asked on February 25, 2012 
ChemistryThermochemistry (grade 12)
Thermochemistry determine the final temperature if 45.67 kJ of heat energy is removed from 18.5 g of H2O (g) at 122 degrees Celsius useful information sp. heat H2O (s) = 2.03 J/g(degree C) sp heat H2O (l) = 4.18 J/g(degree C) Sp heat H2O (g) = 2.01
asked on February 15, 2012 
Chemical kinetics (theory)
Explain why a dust is much more explosive than is a stalk of grain.
asked on March 5, 2012 
Chemical kinetics (chemistry)
if the activation energy is larger from the perspective of the reactants than the products, the reaction is ?
asked on March 5, 2012 
chemistrygasesppm
Nitrogen dioxide reacts with water and oxygen in the atmosphere to produce acid rain. 4NO2(g) + 2H2O(g) + O2(g) = 4HNO3(g) Assuming that the temperature and the pressure remain constant, calculate the volume of air at 1 atm, 20 C, necessary to dilute the
asked on March 1, 2012 
Chemistrygases
Nitrogen dioxide reacts with water and oxygen in the atmosphere to produce acid rain. 4NO2(g) + 2H2O(g) + O2(g) = 4HNO3(g) Assuming that the temperature and the pressure remain constant, calculate the volume of air at 1 atm, 20 C, necessary to dilute the
asked on March 1, 2012 
Chemistrygases
Nitrogen dioxide reacts with water and oxygen in the atmosphere to produce acid rain. 4NO2(g) + 2H2O(g) + O2(g) = 4HNO3(g) Assuming that the temperature and the pressure remain constant, calculate the volume of air at 1 atm, 20 C, necessary to dilute the
asked on March 1, 2012 
stoichiometry
What mass of nitrogen monoxide can be made by the reaction of 8.00 g ammonia and 17.0 g oxygen? correct answer is 12.8 ± 0.1 (g) I keep getting 14.1 g and that the limiting reagent is NH3 What am I doing wrong?
asked on March 1, 2012 
chemistry  Molar enthalpy
When 10.0 g of KOH is added to 100.0 g water, the solution's temperature increases from (25.18 C) to (47.53 C). What is the molar enthalpy of solution for KOH? i tryed q=(m)x(c)x(delta T) didn't really work. i got 22.35 J do i use that to find the molar
asked on February 29, 2012 
chemistry 12  gases
The molecular formula for this compound (14.37% H, density of 1.13 g/L at 24 C and 743 mmHg) is C_H_ I am not sure how to use this information
asked on February 29, 2012 
Chemistry 12  Gases
What volume of oxygen (at 82.1 oC and 713 mmHg) will be produced by the decomposition of 5.71 potassium chlorate? i am not sure what the unit is on the 5.71 ( cause it's not given) so that's not a typo.
asked on February 29, 2012 
Chemistry 12  Gases
A gas is initially at 345 K, 821 torr, and occupies a volume of 5.85 L. What volume will the gas occupy if the temperature and pressure decrease, respectively, to 7 degrees celsius and 0.921 atm?
asked on February 29, 2012 
net ionics for lab
an experiment was conducted by measuring the change in temperature of solutions after mixing them together. After figuring out the KJ/mol, write a net ionic equation for each mixture 1) hydrochloric acid and sodium hydroxide (net ionic equation?) 2) nitric
asked on February 17, 2012 
Chemistry and Science
carbon dioxide is a "greenhouse" gas in that it absorbs energy from the sun, causing heating of the atmosphere and eventually global warming. carbon dioxide is produced from the combustion of carboncontaining fuels such as coal (mainly carbon), natural
asked on February 17, 2012 
chemistryThermochemistry (grade 12)
calculate enthalpy of H for the reaction N2H4(l) + 2H2O(l) > N2(g) + 4H2)(l) Given the reactions N2H4(l) + O2(g) > N2(g) + 2H2O(l) Enthalpy of H = 6.22.2 kJ H2(g) + (1/2)O2(g) > H2O(l) enthalpy of H = 285.8 kJ/mol H2(g) + O2(g) > H2O2(l) enthalpy of
asked on February 16, 2012 
ChemistryThermochemistry (grade 12)
A 65.0 g sample of 0.600 M HI at 18.46 degrees celsius is added to 84.0 g of solution containing excess KOH, also at 18.46 degrees celsius. The final temperature is 21.96 degrees celsius. Calculate the enthalpy of H for the reaction. Assume the specific
asked on February 16, 2012 
chemistry (grade 12)
how much heat will be liberated if 37.8 g of Fe2O3 is allowed to react with 18.7 g of aluminum. Fe2O3(s) + 2Al(s)> Al2O3(s) + 2Fe(s) + 851.5kJ
asked on February 15, 2012

Mad percent of CuS and Cu2S in an ore sample
my answers are a little different because the numbers changed, i got 12.7% for CuS and 75.83% for Cu2S. it almost added to my needed percent of 88.56%. i even tried to recalculate, incause i left out some numbers, but it didn't work, maybe i will try
posted on September 24, 2012 
Mad percent of CuS and Cu2S in an ore sample
i have tried this, and apparently this is not the method, is there another way?
posted on September 24, 2012 
stoichiometry
yep that was defiantly the problem. thank you
posted on March 1, 2012 
chemistry
i think it might be 0.002 L CuSO4 (0.80 mol/L) = 0.0016 mol CuSO4/0.008 L = 0.02 mols/L CuSO4 someone should double check that thou
posted on March 1, 2012 
algebra
i'm not sure there is on a keyboard, maybe in your word documents, if using Microsoft click on inserts and choose the insert symbol, and search through the programmed symbols in the word program.
posted on March 1, 2012 
math
g(c)= 19 x c^2 ? is c squared? if not g(4)= 19 x (4x2) g(4)= 19 x 8 g(4)= 152 if C is squared, i am sure you can now derive the answer with this example. simply plug in the input (4) for c
posted on March 1, 2012 
math please
yes good point! does the 2 represent a 2 or C squared (C^2)
posted on March 1, 2012 
math please
g(4)= 19  (4x2) g(4)= 19  8 g(4)= 11
posted on March 1, 2012 
chemistry  Molar enthalpy
and would the answer be positive because the temperature is increased?
posted on February 29, 2012 
chemistry  Molar enthalpy
haha, yep, ok so q= 10,276.53 J and to get the answer in molar enthalpy should i divide q by the mole of KOH 10.0g KOH (1 mol KOH/ 56.105g) = 0.1782 mol KOH 10,276.53 J / 0.1782 mol KOH = 57,668.5J/mol = 57.6 kJ/mol Is this right?
posted on February 29, 2012 
Chemistry  Enthalpy reactions
perfect, i got a positive 178.3 kj/mol, which makes since because CaCO3 releases a lot of energy when it breaks apart, so there was more energy released when breaking apart then needed to originally form CaCO3 Thank you
posted on February 29, 2012 
Bio please help!
*membrane transport via proteins (active transport) membrane proteins act as enzymes to catalyze vital processes of the human body. membrane proteins, cell to cell recognition
posted on February 29, 2012 
chemistry 12  gases
Thank you, that was awesome, I think i got the right answer now C2H4 is the molecular formula
posted on February 29, 2012 
Chemistry 12  Gases
never mind, i found out it was suppose to be in grams, and i figured out the answer.
posted on February 29, 2012 
algebra
divide the original answer by 3 and get 12Z^2 + 32Z + 5 = 0 now find common factor of 12, that work for the equation (6Z + 1)(2Z +5)=0 6Z = 1 z= 1/6 2Z = 5 Z= 5/2 now plug each Z value in to the equation (one at a time) and see which Z value lets the
posted on February 29, 2012 
HARDEST MATH QUESTION IN THE UNIVERSE
I just answered a question like this a couple questions below this post!
posted on February 29, 2012 
HELP ON MATH PLEASE!!!!!!!
i would think first find the average of her running speed = 4 m/hr + 6 m/hr = 10 m/hr divided by 2 = an average of 5 m/hr now 5 m/hr = 1.25 hr 1.25 hr x 5 m/hr = 6.25 miles Hope that helps, the questions seems a little vague so that's why finding an
posted on February 29, 2012 
algebra
50 < X < 65 X has to be even, and between 50 and 65 X (could be)= 52, 54, 56, 58, 60, 62, 64 Now which one of these numbers is divisible by 5 and gives a whole number answer divide each possible X value by five and see which one gives a whole number answer
posted on February 29, 2012 
Math
discrete, is whole numbers like (0, 1, 2, 3, 4). they are countable. continuous is not whole numbers (o.976, 1.456, 2.2, 3.4) They are not whole numbers, and they are usually used when measuring something like time of a movie, length of a car. there is
posted on February 29, 2012 
math
Depends, where are you? in america or canada? Canada = metric system the standard SI unit for weight is kg America = Imperial system standard unit for measuring weight in imperial? ounces or pounds? These are the questions that will answer your question.
posted on February 29, 2012 
math
text book = 50 + (2 x Z) let Z= workbook textbook + workbook = 230 pages [50+(2Z)] + Z = 230 50 + 3Z =230 3Z= 180 z= 60 Text book = 50 + 2Z text book = 50 + 2(60) Text book = 170 REMEMBER: 50 more, really means "plus 50" in an equation 2 time the number of
posted on February 29, 2012 
Elementary statistics
THANK YOU SO MUCH I have been stumped on this question for hours on two different occasions, I am so glad you cleared this up for me.
posted on February 29, 2012 
chemistryThermochemistry (grade 12)
You are defiantly right. it is suppose to be 2H2O2(l) and 4H2O(l) and the first equation is suppose to be 622.2 kJ/mol actually they are all suppose to be kJ/mol, but that was a typo on the exercise. For a final answer I got 818.2 kJ/mol i used the first
posted on February 16, 2012 
physics
Force = mass x Acceleration Rearrange the formula to Acceleration = force/mass acceleration = 10,000N/ 1250kg acceleration = 8m/s^2 now remember this is an applied force to slow down the car (because the brakes are applied) therefore the car is not
posted on February 16, 2012 
ChemistryThermochemistry (grade 12)
Awesome I am defiantly starting to understand this stuff better. .065L x (.600 mol/L) = 0.0390 mol q=MC(delta T) = 149g x 4.184 J/g(C) x 3.5 celsius = 2181.9 J =2.2 kJ Then I did 2.2 kJ / 0.0390 mol = 56 kJ/mol for my final answer I got 56 kJ/mol
posted on February 16, 2012 
ChemistryThermochemistry (grade 12)
Thank You for my final temperature I got around 83.1 degrees celsius
posted on February 16, 2012 
chemistry (grade 12)
Thank you I checked to see which one is the L.R, which it is Fe2O3, then i converted grams into moles and then converted those moles in to heat released and got 201.5 kJ This is the first time i have been on here, if any one wants to confirm that is the
posted on February 15, 2012