Questions Asked on
May 20, 2007

Chemistry II
C4H4 (g) + 2 H2 (g) > C4H8 (g) Combustion reactions involve reacting a substance with oxygen. When compounds containing carbon and hydrogen are combusted, carbon dioxide and water are the products. Using the enthalpies of combustion for C4H4 (2341
asked by Jayd 
algebra
If v1,...,v4 are in R^4 and v3 is not a linear combination of v1, v2, v4 then {v1, v2, v3, v4] is linearly independent. Is this true or false? Why? If v1,...,v4 are in R^4 and v3 is not a linear combination of v1, v2, v4 then {v1, v2, v3, v4] is linearly
asked by Ashley 
Math
How do I solve this problem? There are 8 sections of seats in an auditorium. Each section contains at least 150 seats but not more than 200 seats. Which of the followin could be the number of seats in this auditorium? What are your choices? Multiply 150 x
asked by Mack 
Algebra
How many pivot columns must a 5x7 matrix have if its columns span R^5? Why?
asked by Ashley 
Math
The table shows some values for the function f. If f is a linear function, what is the value of a+b? a24 b36 c48 d72 eit cannot be determined from the information given. x f(x) 0 a 1 24 2 b The Answer is c48. How did they arrive at that answer????????? The
asked by Mack 
physics
A student conducted an experiment to determine the resistance of a lightbulb. while performing the experiment the student noticed that the lightbulb began to glow and became brighter as she increased the voltage. of the factors affecting resistance, which
asked by koeit 
Math
I don't understand this!!! If rstv=1 and stuv=0, which of the followin must be true? a.r
asked by Mack 
English
Does anybody know any websites that will give me information on the benefits and salaries that a store manager and a hand model( jewelry and perfume) earns http://www.payscale.com/research/US/Job=Retail_Store_Manager/Salary I could find no information on
asked by Ron 
Chemistry II
The enthalpy of neutralizatino for the reaction of a strong acid with a strong base is 56 kJ/mol of water produced. How much energy will be released when 230.0 mL of 0.400 M HCl is mixedwith 150.5 mL of 0.500 M NaOH? How much water is produced in the
asked by Jayd 
Chemistry II
The enthalpy of neutralizatino for the reaction of a strong acid with a strong base is 56 kJ/mol of water produced. How much energy will be released when 230.0 mL of 0.400 M HCl is mixedwith 150.5 mL of 0.500 M NaOH? How do I figure out how much water is
asked by Jayd 
Chemistry
Hydrogen iodine is a strong acid that is used in chemical synthesis to produce some common drugs as well as a source for iodine, I2. Data for the formation of hydrogen iodine was obtained as shown. The reaction was found to be first order with respect to
asked by Christian 
cells
what are the properties of blood cells. Since this is not my area of expertise, I searched Google under the key words "blood cells" to get these possible sources: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/B/Blood.html
asked by Nicolas 
equations of tangents and normals
hi, i'd really appreciate some help solving this question! I am completely at loss here :/ The question is to: Find the equation of the normal to y=loge(x+2) which is parallel to the line with equation y+3x5=0 I am fine at solving these sorts of equations
asked by elle 
chem
What advantage is there to adding salt to cooking water? and what conditions are necessary for ideal carbonation of a beverage? please help http://www.miniscience.com/projects/Saltwater/index.html http://www.physlink.com/Education/askExperts/ae643.cfm
asked by Horacio 
maths
the function y = 5 + 3 sin (pie t /3 + pie /2) choose one option which gives the value of the funtion when t = 3. choose the option which gives the period of the function. from the options below. 0, 1/6, pie/6, 2, 3, pie, 5, 6 wod the value of t=3 be 5 ?
asked by kat 
Algebra
Write the equation of the line passing through the given point with the indicated slope. Give your results in slopeintercept form. Point: (0,5) Slope: m=3/5 Show equation I will be happy to critique your work on this.
asked by Linda 
Algebra
Write the equation of the line passing through the given pair of points. Write your result in slopeintercept form. (1,3) and (4,2) Show equation I will be happy to critique your work on this. y3=1(x+1) y3=1x+1 y=x+2?
asked by Linda 
Algebra
Write the equation of the line passing through the given pair of points. (2,3) and (2,4) I will be happy to critique your work on this.
asked by Linda 
Algebra
Write the equation of the line L satisfying the given geometric conditions. L has yintercept (0,2) and is perpendicular to the line with equation 2x3y=6 Show work I will be happy to critique your work on this. 3x+2y=4?
asked by Linda 
Algebra
Write the equation of the line L satisfying the given geometric conditions. L has yintercept (0,3) and is parallel to the line with equation y=2/3x+1 I will be happy to critique your work on this. y=(2/3)x3?
asked by Linda 
Algebra
In planning for a new item, a manufacturer assumes that the number of items produced x and the cost in dollars C of producing these items are related by a linear equation. Projections are that 100 items will cost $10,000 to produce and that 300 items will
asked by Linda 
maths
Choose three options which are true: a) an angle of 150 degrees is equivalent to 2pie/3 radians. b) Cos 0 = cos (0 – pie/2) for al values of 0. c) Sin 0 = cos (0 – pie/2) for all values of 0. d) If triangle ABC has a right angle at B, then sin A = cos
asked by sarah 
Matrh
How do you solve this problem? The avera&e (aritmeticmean)of x and y is 5 and the avera&e of x, y, and z is 8. What is the value of z? (a)19 (b)14 (c)13 (d)11 (e)3 I solved it by addin 8+5=13 So I chose (c)13. But it's wron& and the answer is (b)14. How
asked by Mack 
Chemistry
Our teacher asked, a few weeks ago, for us to find the pH of 7.65 E11 M HClO3. We were told that we couldn't find the pH simply by log[7.65E11]. He said that we had to account for the water somehow [I think we had to do something with the number 1.0
asked by Krystal 
Math
If 4 less than 3 times a certain number is 2 more than the number ,what is the number? a.1 b.3 c.1 d.2 e.3 Do I solve it like this: 3n4=n+2?? If so, how do I solve this problem? You have the equation right.
asked by Mack 
acid base chem
I'm reviewing my notes for a test tomorrow, and I found that I have a question concerning acids that under go multiple protonizations. I know the molarity [or moles, if that's being calculated] of H3O+ of the first protonization can be found using the Ka,
asked by Krystal 
physics
how can i calculate the slope of the bestfit line in a length v.s. resistance(x=length;y=resistance) graph where the plotted points are: (5.1,1.6)(11.0,3.8)(16.0,4.5)(18.0,5.9)(23.0,7.5)? Personally, I would graph the points, and draw a best fit line,
asked by koeit 
alg.
solve and graph 2xy=4 2xy=6 would this be x=2+0.5y x=3+0.5y and then graph as that??????? not really sure what i am doing here Put both equations in the form of y=mx +b Then observe that the slope is the same, the lines are parallel, and have no common
asked by clueless 
Science
How do clouds form, and where in canada would you expect to see certain types of clouds. What is the difference between clouds and fog? http://en.wikipedia.org/wiki/Cloud
asked by Erica 
english
for english i have to do a project and it can be on anything i want. i have to have a persuasive essay and a how to and the history on the subject. like my friend is doing ice cream and we are making it in class. my other friend is doing texting and having
asked by anonymous 
Chemistry II
The total volume of hydrogen gas needed to fill the Hidenbrug was 2.0e8 L at 1.0 atm and 25 degrees Celsius. How much heat was evolved when the Hidenburg exploded, assuming all the hydrogen reacted?
asked by Jayd 
calc 2
given x=2cos(t)+t*sin(t) and y=2sin(t)t*cost(t), with t:[pi, 2pi] find all critical values. by finding dy/dx and setting it equal to zero, i only find one value, t=6.121, within that domain. that gives you x=.987. I'm suppose to get three other answers.
asked by Mischa 
maths
For the formula Y = AX + B to make X the subject wod it be X = AY – B ?? no ax+b=y subtract b from both sides, then divide both sides by a.
asked by R 
Chemistry II
Calculate the change in heat: 2 Na(s) + 2 H2O(l) > 2 NaOH(aq) + H2(g) So far this is what I have: 2 H20 > 2 H2 + O2 2(285.83) kJ 2 Na + O2 + H2 > 2 NaOH 2(426.73) kJ 2 Na + 2 H2O > 2 NaOH + H2 281.8 kJ If this correct?? yes, correct, as best as I
asked by Jayd 
Chemistry II
The total volume of hydrogen gas needed to fill the Hidenbrug was 2.0e8 L at 1.0 atm and 25 degrees Celsius. How much heat was evolved when the Hidenburg exploded, assuming all the hydrogen reacted? I will be happy to critique your thinking on this. First,
asked by Jayd 
Math
3,5,5... The first term in the sequence of #'s shown above is 3. Each even # term is 2 more than the previous term and each odd # term, after the first, is 1 times the previous term. For example, the second term is 3+2, and the third term is (1)x5. What
asked by Mack 
science
what steps can be taken by rwanda to reduce degradetion and deforestation (Broken Link Removed) I don't know what you mean by degradetion, but deforestation, the way to reduce it is to control the forests: who is there, who does what, and when. I frankly
asked by cynthia 
Chemistry II
The total volume of hydrogen gas needed to fill the Hidenbrug was 2.0e8 L at 1.0 atm and 25 degrees Celsius. How much heat was evolved when the Hidenburg exploded, assuming all the hydrogen reacted? 2.0e8 L H2/22.4 L H2 = 8.9e6 mol H2 For every 2 mol H2
asked by Jayd 
ethics
write a memo explaining how you would enhance communication during a business trip to another country. We'll be glad to critique your memo. Thank you for using the Jiskha Homework Help Forum. Since you say a "memo" you might like the following site from
asked by Sharon 
language
I need to write a paragraph describing my utopian community. What is your ideal community? If you post your paragraph, we'll be glad to comment on it. Thank you for using the Jiskha Homework Help Forum. You only have to write ONE paragraph? Here's how to
asked by donna 
PreCalculus
How can the following two identities be verified? 1. (cos^2y)/(1siny)=1+siny 2. sin^2asin^4a=cos^2acos^4a Thanks! change cos^2a to 1sin^2a=(1sina)(1+sina) Thank you. I figured out the first one with your help, but I'm still stuck on the second. Any
asked by Corin 
algebra
1. (3sqrt6)/(52sqrt6) 2. (2sqrt3sqrt6)/(5sqrt3+2sqrt6) Don't you do something with the conjugate or something like that? 3sqrt6 5+2sqrt6  x  52sqrt6 5+2sqrt6 yes, exactly. Multiply out the numerator, and in the demoninator you will
asked by Emily 
Chemistry
How does one calculate the pH of a solution that is only 1.84% ionised? determine the concentration of the H+, which will be in a monoprotic acid, concentration * decimal percent. then determing pH in the normal way.
asked by Fiona 
chemistry
Does anyone know what advantage there is to using hot water to make ice cubes? Validated tests indicate it is faster to freeze because it has less dissoved air, some of it evaporates, and that evaporation cools it rapidly, and in the end, because some of
asked by Lillian 
Chemistry II
I will be happy to critique your thinking on this. First, calculate the moles of H2 used. 2.0e8 L H2/22.4 L H2 = 8.9e6 mol H2 For every 2 mol H2 used 572 kJ of energy is produced 572 kJ/2 mol H2 = 2.86e2 kJ/mol I have a balanced equation with this
asked by Jayd 
Chemistry
If the hydrochloric acid is warm, is the following equation correct? 2HCl(aq) + Na2SO3 > 2NaCl(aq) + SO2(g) + H2O(l) yes, correct.
asked by Fiona 
Math
Solve the system by graphing by any method of your choice. 3xy=1 or y=3x1 3xy=2 y=3x2 (0,1),(2, 5)and(0,2),(2,4) Solution is Consistent, lines intersect at (1/4, 5/4). Above is my answer but I keep coming back to this again and again. Am I missing
asked by Amanda 
math [radicals]
how do you multiply a radical with a regular number ? for example: 4radical2 ( 2+ 2radical3) first term: 4sqrt2 * 2= 8sqrt2 second term 2sqrt2 * 2 sqrt3= 2*2 * sqrt (2*3) = 4 sqrt6 first term: 4sqrt2 * 2= 8sqrt2 second term 2sqrt2 * 2 sqrt3= 2*2 * sqrt
asked by courtney 
science
Identify 2 everyday things affected by change in altitude. One I have as airplanes. boiling temperature of water. air pressure The type of plant growth would be another factor. Since the animal life depends on the plants, animals present at various
asked by Ginevra 
calc please help
given x=2cos(t)+t*sin(t) and y=2sin(t)t*cost(t), with t:[pi, 2pi] find all critical values. (4 answers)
asked by Mischa 
Algebra
Find the GCF for each of the following groups of numbers. 36, 54, and 180 Find the LCM for each of the following groups of numbers. Use whichever method you wish. 8, 15, and 20 can anyone IM me or email how to SIMJPLIFY RADICAL EXPRESSIONS please?
asked by Dave 
MATH
I am having lots of trouble with SIMPLFYIGN RADICAL EXPRESSIONS can anyone help>? Please
asked by James 
Calculus
I don't understand what the graph is suppose to show and what the integral equation is suppose to mean. How would I use the graph to answer the questions? f is the differentiable function whose graph is shown in the figure. The position at time t (sec) of
asked by Anonymous 
socila studies^^ ! help
name at lease 5 important event that took place in the history of texas.(NOTE: historical events are important things that happened in the past.do not put annual events here.) http://en.wikipedia.org/wiki/History_of_Texas a major confederate blunder which
asked by vicky 
Math Help please!!
Could someone show me how to solve these problems step by step.... I am confused on how to fully break this down to simpliest terms sqrt 3 * sqrt 15= sqrt 6 * sqrt 8 = sqrt 20 * sqrt 5 = since both terms are sqrt , you can combine them. sqrt 3* sqrt 15=
asked by Reggie 
World History
Hi, I am preparing a presentation on Argentina 20th century history which covers the country economically, socially and politically. Are there any websites that may help me with the social history of Argentina during the 20th century? Thanks
asked by Frank 
algebra
can anyone tell me about polynomials please You need to be more specific in your question. Polynomials is just about half of a beginning algebra course.
asked by lily 
english
I find it at http://en.wikipedia.org/wiki/Cagoule There is a relationship  what the people referred to in the second link wore  a cowl ( http://www.answers.com/cowl ). I think the origin is French, but I can't find anything specific either. =( Thanks
asked by Writeacher 
parabolas
how do i find the equaion of the following parabolas? 1)intercepts at (2,0),(8,0) and (0,48) 2)turning point at (1,2) and passing through the origin. can someone please teach me how to do this??thanks! The first: Write you standard equation of a parabola
asked by Emma 
SCIENCE HELP
Can anyone anyone please help me or guide me to a web site where I can find this information? Thank you. Dolphin and porpoise populations are endangered by the _________ fishery. I have twenty questions to complete on my paper and I found all the answers
asked by Meg 
Math
Solve the system by addition or substitution. 3x – 4y = 8 6x – 2y = 10 Please get me on the correct track for 3x 4y =8 x=4, y=1 for 6x  2y =10 x= 2, y= 1 Solve one equation for x. 3x = 4y + 8 x = (4y + 8)/3 Insert that value for x in the other
asked by Amanda 
Physics
Any help pleeeze!! I'm totally lost on these!! 1. A 14 g coin slides upward on a surface that is inclined at an angle of 16° above the horizontal. The coefficient of kinetic friction between the coin and the surface is 0.23; the coefficient of static
asked by L.A. 
Bio...DNA
Can anyone explain the relationship between the structure of DNA , protein structure and phenotype of an organism? Also, what is the role of DNA in protein synthesis? I will give you a little hint. The DNA makes the RNA. The RNA makes the proteins by amino
asked by Pet 
chemistry
What is the acid and base whose reaction will produce the salt Na3PO4? What is the acid and base whose reaction will produce the salt PbS? What is the acid and base whose reaction will produce the salt KIO3? phosphoric acid, sodum hydroxide lead hydroxide,
asked by Carter 
maths
How to calculate the mean number of threatened fishes, where total number of fishes is 29300 and number of threatened fishes is 1173. Hmmmm. you have one data point, that is, 1173 fish are threatened. The mean of one number is that number. Is there
asked by Ellie 
Algebra
Find the slope of any line perpendicular to the line through the points (0, 5) and (3, 4). Show work Find the slope of the line through the two points: slope= (y2y1)/(x2x1) you do that. Now the slope of the line perpendicular to this is the negative
asked by Linda 
Algebra
Write the equation of the line passing through the given point with the indicated slope. Give your results in slopeintercept form. Point: (0,5) Slope:m=3/5. Show work Well, youknow the form is y= mx+b you are given m. You are given a point (0,5) Put that
asked by Linda 
BiO
I am comfused about meiosis and mitosis. First of all, both are forms of asexual reproduction, right? I know that in mitosis, you end up with two offspring. In meiosis, you end up with four. I don't get the part about the chromosomes. If you start out with
asked by Anonymous 
Chemistry
The enthalpy of solution of CaCl2 is 82.88kJ. If the specific heat of the solution is 4.184J/g*C and the calorimeter constant can be neglected, what will be the final temperature after 5.36g of CaCl2 is dissolved in 100.0g of H2O at 25.0C? I assume the
asked by Em 
Algebra
Find the slope of the line through the following pairs of points. (4,3) and (5,3) equals to 0 Notice the y is constant, this is a horizontal line, zero slope.
asked by Linda 
Algebra
Write the equation of the line passing through (3,10) and (3,3) Notice the line is vertical. Equation is x= constant. You figure what the constant is.
asked by Linda 
physics
where should a voltmeter that used to determine the potential diference across the circuit, locate in a parallel circuit? The voltmeter should be in parallel with the circuit.
asked by koeit