# chemistry! URGENT

61,442 results, page 25

1. ### math urgent :(

1.)A number decreased by 32 is -58. Find the number. The number is ____. (Give only the value of the number as your answer. 2.)The product of 14 and n is -28. Write the algebraic equation 3.)A blue bike is \$14 less than a red bike. The sum of their prices is \$300. How much is ...
2. ### Urgent algebra help!

Here's my question. Please walk me through it so I can fully understand it. Jon begins jogging at a steady 3 meters/sec down the middle of Lane #1 of a public track. Laaura starts even with him in the center of Lane #2 but moves at 4 meters/sec. At the instant they begin, ...
3. ### Chemistry

Does anyone know of any sites that make learning to balance equations easy? I just transferred to a new school and the chemistry class is way ahead of my old class. I really don't get it. Please help since there is a test tomorrow and it's on stuff that you have to be able to ...
4. ### AP Chemistry

In a ﬁt of boredom, a chemistry teaching assistant swallows a small piece of solid dry ice (CO2). The 8.9 g of dry ice are converted very quickly into gas at 311 K. Assuming the TA’s stomach has a volume of 1.5 L, what pressure is exerted on his stomach?
5. ### Chemistry

Hi there, can someone please help me with this chemistry problem? Write the equation for the acid-base reaction that takes place when nitric acid (HNO3) dissolves in H2O. (Include the phase of each substance.) I got HNO3(aq) + H2O --> H3O+(aq) + NO3−(aq) but the answer is...
6. ### Chemistry

I know that this is an off topic question, but I need you to respond to this.... I received barely an A in my chemistry class, and my teacher gave me a 2/25 on an assignment... Although I got that grade, I still have an A.. I asked my teacher why and she said that it is not ...
7. ### Chemistry

I know that this is an off topic question, but I need you to respond to this.... I received barely an A in my chemistry class, and my teacher gave me a 2/25 on an assignment... Although I got that grade, I still have an A.. I asked my teacher why and she said that it is not ...
8. ### Chemistry

When 155 mL of water at 26 degrees Celsius is mixed with 75 mL of water at 95 degrees Celsius, what is the final temperature of the mixture? (d Water = 1.00 g/mL) Im really stuck on this problem and chemistry isnt exactly my strong point, thanks in advance!
9. ### Microconomics [URGENT]

In the short run, do perfectly competitive firms have a loss of profit or a break even when MC = AVC? Do these firms choose whether to produce or shutdown or both? Do they choose to produce nothing or a specific quantity or both? If MC = ATC in the short run for perfectly ...
10. ### English

Can someone check my sentences? They are really urgent. Thank you in advance. 1) The Reformation was caused by the refusal of Pope Clement VI to declare invalid Henry VIII's marriage to Catherine of Aragon. 2)Elizabeth I continued her father's policy. She defeated the Spanish ...
11. ### College chemistry

This is my first time taking chemistry and I am VERY VERY confused On the step involved to find out how many calories to warm 58mL of water from 10 degress C to 100 degress C and vaporize it at 100 degress C.
12. ### CHEMISTRY

When doing an ICE Chart in Chemistry, when do you know whether the C is a negative or positive? I was told if the problem gives us reactant concentrations and no product concentration then the reaction goes forward and make the reactant lose and the product gain for example I2...
13. ### Chemistry

I've run into some difficulty with my chemistry homework. We went over this practise question in class today as an example. However, I wasn't able to fully grasp how to work it out. "How many grams of nitrogen form when 34.6 grams of nitrogen dioxide decomposes according to ...
14. ### probability

The probability that a student passes Biology is 0.35 and the probability to pass Chemistry is 0.63. If the probability to pass both Biology and Chemistry is 0.4, what is the probability that he will pass either Biology or Chemistry?
15. ### Statistics

In how many different ways can a chemistry book, a calculus book, a history book and a dictionary be arranged on a shelf so that the chemistry book or the history book appears first?
16. ### chemistry

I am enrolled in analytical chemistry after a 4 year break from any chemistry. I was recently given a problem set and I need some help on the following: A 0.899g sample containing epsom salt, MgSO4 & 7 H2O, and other non-hydrated materials was dehydrated completely in a stream...
17. ### Physics urgent help have a test!!!

1. a little spider monkey named flo has stolen a bunch of bananas from her older brother Charley and is now running away frm him with the bananas in hand. She sees salvation in a long vine and grabs the bottom, hoping to swing away a) if she has a mass of 5.3kg and the bananas...
18. ### math

The quadratic equation frequently appears in both the equilibrium and acid-base sections of General Chemistry. Therefore, it is useful to refresh the use of the quadratic before applying it to chemistry questions. Which of the following answers is a viable solution to the ...
19. ### Chemistry Lab

Im preparing my report for Synthesis of Alum chemistry lab. Need help with these 2 questions: 1-What other cations besides aluminum can be used to make alum crystals? Explain 2-Why we need to add sulfuric acid slowly to the solution as opposed to pouring it fast?
20. ### Chemistry

How would you scale down an organic chemistry experiment? Would you have to know an expected percent yield to scale it down?
21. ### chemistry

what is an indicator for chemistry? How is this for a definition? Thanks A susbtance that changes colour when added to a base or an acid. The colour it changes to will depend on which it is added to.
22. ### chemistry

I've been doing organic chemistry and I don't really understand how to draw some isomers. I know how to draw the easier isomers like Butan-1-ol and Butan-2-ol but I don't get how there can be other ones and how to draw them...please help
23. ### chemistry help

our teacher said on our final chemistry lab test there will be a question asking us to convert nanometers to wave numbers, anyone know what the question might be phrased like? also, im not sure i know how to convert, anyone have an example question with the steps?
24. ### Math

At small town high there are 100 students,each of whom takes atleast one of Biology,Chemistry,or physics.There are 50 student in Biology,60 in chemistry,and 70 in Physics.If 24 students are enrolled in exactly two of the classes,how many students are in all three?
25. ### soial studies

Who helped create christianty,Judaism,& Islam. Where were they created,what are they,& when were they created. Thanks :) These sites will help you with this information. http://en.wikipedia.org/wiki/History_of_Christianity http://en.wikipedia.org/wiki/Muslim_history http://www...
26. ### chemistry

Under the appropriate conditions, NO forms NO2 and N2O: 3NO(g) <--> N2O(g) + NO2(g) Use the values for delta G naught for the following reactions to calculate the value of Kp for the above reaction at 500.0 C 2NO(g) + O2(g) <--> 2NO(g) delta g=-69.7 kJ 2N2O(g) <...
27. ### statistics.. URGENT!! PLZ!!

In a learning experiment, untrained mice are placed in a maze and the time required for each mouse to exit the maze is recorded. The average time for untrained mice to exit the maze is µ = 50 seconds and the standard deviation of their times is ? = 16 seconds. 64 randomly ...
28. ### chemistry

What is the theoretical yield of H[2]O (in grams) if 8.3 mol H[2]S were consumed in the above reaction? If 137.1g of water was actually collected after the reaction, what is the percent yield? I have no idea to do this problem. I am not good in math at all and currently taking...
29. ### chemistry

In the chemistry exp molar mass of a volatile liquid what will be the outcome if the hole in the aluminu foil was larger would it make the molar mass high or low. Or what will happen if yhr water vapors condensed under the aluminum foil before the final weighing
30. ### chemistry

In Chemistry: what is ph during the titration of 20.00ml of 0.1000m triethylamine (ch3ch2)3n (kb=5.2x 10-4) with 0.1000m HCL solution after the additions of titrant : a) 0ml (b) 10.00ml (c) 19.00ml (d)15.00ml (e) 20.00ml (f) 25.00ml
31. ### Organic chemistry

please help me with these what are the functional group(s) in Lexiva (Fosamprenavir Calcium)? i only know that it has an amine group but i'm not sure if there is another group!!! and how can i relate Lexiva to chemistry?(ideas please)
32. ### Chemistry

Hi, Does anybody know a list of websites that have a list of short labs (3-5 min) on chemistry? I hope these are of some help. http://www.chemistrycoach.com/Links%20to%20chemistry_experiments.htm http://chemistry.about.com/od/demonstrationsexperiments/...
33. ### Physics -- URGENT

Estimate the force a person must exert on a string attached to a 0.200 kg ball to make the ball revolve in a circle when the length of the string is 0.600 m. The ball makes 1.40 revolutions per second. Do not ignore the weight of the ball. In particular, find the magnitude of ...
34. ### physics(URGENT!!!!!)

A ruler stands vertically against a wall. It is given a tiny impulse at θ=0∘ such that it starts falling down under the influence of gravity. You can consider that the initial angular velocity is very small so that ω(θ=0∘)=0. The ruler has mass m= ...
35. ### physics(URGENT!!!!!)

A ruler stands vertically against a wall. It is given a tiny impulse at θ=0∘ such that it starts falling down under the influence of gravity. You can consider that the initial angular velocity is very small so that ω(θ=0∘)=0. The ruler has mass m= ...
36. ### Chemistry

Can Someone describe the structure of ionic compounds for me please.. Ionic compounds consist of a three dimensional array network of + and - ions. I expect you already know that. As to structure, here is a web site that may help. Repost if you have additional questions but ...
37. ### Chemistry

I was doing a lab today in chemistry, and I do not know if I got my measurements correctly. My teacher gave us a strip (probably 5inches) of Mg. We measured it, and then after that, we had to burn it, and measure the mass of it after it was burn. Would the burned Mg have more ...
38. ### Chemistry: Electron Configurations

Write the electron configuration for the following ion. V3+ I got 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2. In simplified form, I got [Ar]4s^2. I checked my answer against the answer given in the back of my chemistry textbook, and the two didn't correspond. The answer my book gives is [...
39. ### Green Chemistry

The primary route for making copper iodide is by reacting potassium iodide with copper sulfate: 2CuSO4 + 4KI + 2Na2S2O3 ==> 2CuI + 2K2SO4 + 2NaI + Na2S4O6 Identify potential green chemistry and green engineering challenges of the reaction.
40. ### science urgent help

What is the independent variable? Select one option from the list below. 1 is the correct answer help me please .thanks Sue is setting up an experiment to test whether fly maggots select a dark or a brightly lit environment. She sets up a chamber in which there is a gradient ...
41. ### Calculus Help Please!!! URGENT!!!!

Carbon-14 has a half-life of 5700 years. In a living organism, the ratio of radioactive carbon-14 to ordinary carbon remains fairly constant during the lifetime of the organism. After the organism’s death no new carbon is integrated into the organism’s remains, so the ...
42. ### science urgent need help

What is the independent variable? Select one option from the list below. 1 is the correct answer help me please .thanks Sue is setting up an experiment to test whether fly maggots select a dark or a brightly lit environment. She sets up a chamber in which there is a gradient ...
43. ### Chemistry

Hi, I am totally confused with this chemistry because none of this stuff is in my book, so I come to the great ones with my question: 1. Can you show me how to convert celsius to farenheit (please show me an example and your work so I can get it please) 2. farenheit to kelvin...
44. ### Yr 10 English URGENT

"Write a creative description of a journey you have taken. Focus on the means of transportation and the nuances in particular to that way of travel. Select 10 words from the spelling list to use in your piece of writing and write in the space provided on the answer sheet." The...
45. ### French (URGENT)

Sra, can you please proofread my paragraph? Bonjour, Ici un petit paragraphe à propos de mon ami James. James est d'Alberta mais il habite Vernon, BC de Canada. Il a quinze ans. Il a un frère cadet nommé Thomas. Thomas a quatorze ans. James aime utiliser son reluisant noir ...
46. ### Chemistry

Explain in terms of forces between structural units why H2O2 has a higher melting point than C3H8. Also, which between the two examples has a lower boiling point? NH3 or AsH3 C3H7OH or C2H5OCH3 Can you possibly give me a good website that simply explains hydrogen bonding/...
47. ### chemistry

The decomposition of an aldehyde solution in carbon tetrachloride is a first order reaction with a rate constant of 1.20 x 10-3 min-l. If we start with [aldehyde] = 0.0500 molar, what will the concentration be 150 minutes later? a. 0.00900 M b. 0.0418 M c. 0.00926 M d. 0....
48. ### Chemistry

A single 4p orbital can hold how many electrons? i got 6 is that correct or no? Chemistry - Anonymous, Friday, September 10, 2010 at 2:52am "That is correct! px, py and pz (2 electrons in each) " since it's asking about a SINGLE 4p orbital would it be 2? i don't fully ...
49. ### Chemistry

I need definitions for chemistry and I can't come up with any heterogeneous reaction homogeneous reaction activation energy activation energy activated complex elementary reaction
50. ### chemistry

I have a question in chemistry relating to identifying a compound that would precipitate the iron ions out of a water supply. I am unsure of a compound that would react to produce the iron as a precipitate that could be removed. Thoughts?
51. ### Chemistry

1. How could a chemistry student change NaOH(s) to NaOH(aq)? s= solid aq= aqueous 2.) How could a chemistry student change NaOH(s) to NaOH(l) s= solid l= liquid
52. ### Chemistry

Concentration 15.8 mg/L Final Volume 100.0 mL What is the concentration of phosphate in the original lake water sample if the unknown lake water sample in the option has been diluted by taking 25.0 mL of lake water and diluting it to the indicated final volume? •Chemistry - ...
53. ### Math

At Small Town High there are 100 students, each of whom takes at least one of biology, chemistry, or physics. There are 50 students in biology, 60 in chemistry, and 70 in physics. If 24 students are enrolled in exactly two of these classes, how many students are in all three?
54. ### Chemistry

Chemistry - Sri2734 yesterday at 8:11pm 1) Find the pH of 0.54 M C5H5N(aq) given that its Kb = 1.7×10^-9. The answer I got is 2.75 but I got it wrong. The answer is supposed to be 9.48. Why? 2) Find the pH of a 0.864 M NH4Cl solution given that the Kb of NH3 = 1.8x10^-5 at 25...
55. ### physics (Urgent)!!!!!!!!!!!!!!!!!!!!!!

A pendulum of mass m= 0.9 kg and length l=1 m is hanging from the ceiling. The massless string of the pendulum is attached at point P. The bob of the pendulum is a uniform shell (very thin hollow sphere) of radius r=0.4 m, and the length l of the pendulum is measured from the ...
56. ### Organic Chemistry

Does anybody know of a website that explains organic nomenclature ? ...something along the lines "organic nomencluture for Dummies" would be great :-) I'm stuggling to underatand "Z-3-Bromo-6-methyloct-3-ene" let alone draw it ! Here is a site that might just be what you are ...
57. ### Chemistry

Find the value of delta H net for the following equation: SnBr2(s) + TiCl4(l) -> TiBr2(s) + SnCl4(l) I know that I already posted this once but I am still lost on what to do. I know that TiCl4=-804.2 and SnCl4=-511.3 but I thought that the values for SnBr2 is 0 as well as ...
58. ### math/ chemistry

so I have this chemistry problem which involves math and basically I need to convert 62 g/mol into mol/L but I don't know how. like do you DIVIDE the g/mol by 1000 to convert g to L? and then how to you get the mol to become the numerator?
59. ### US Gov help URGENT

I'm very ignorant when it comes to politics. I had to write a summary on Shutdown looms: Spotlight now on Senate after Boehner wrangled House GOP votes If you go to google and type that in it's the first link.. Can someone give me some key pointers as to how the info in that ...
60. ### Chemistry

For Chemistry, I have to design a coin. What are some anti-counterfeiting measures I could use to prevent people from replicating it? I've googled this, but I haven't found many good ideas. I can only think of putting grooves on the edge of the coin and, and making it of an ...
61. ### organic chemistry

a careless organic chemistry student was performing "competing nucleophiles in nucleophilic substitution reactions" experiment , and left his container of tert-butyl chloride and tert-butyl bromide open to the air for several hours. what happened to the composition of the ...
62. ### chemistry

I'm working on substitution organic chemistry problems and I just had a question. There's an equation in which a molecule is treated with methanol in an acetone solution. Would the reaction be SN1 or SN2? I thought that it was SN2 because of the aprotic acetone, but the answer...
63. ### English

Could you please check these sentences,please? It's really urgent. I made some changes and I would like to know if they are correct. 1) The interior monologue has the following features. First, it is immediate since it lacks the conventional syntax and it is free from ...
64. ### Chemistry

Hello, we recently did a lab in our chemistry class to analyze an Unknown amount Calcium Carbonate which was titrated with EDTA. Our titration results were: mass of the unknown CaCO3 was 0.172 g and the mL of EDTA added was 30.7. How do I find the percent mass of Ca?

Newton’s Law of Cooling states that the temperature of a heated object decreases exponentially over time toward the temperature of the surrounding medium. The temperature u of a heated object at a given time t can be modeled by the following function: u(t)=T+(u-T)e^kt K<0...
66. ### help needed !!! URGENT

Can some one help me I don’t know what to take out from the aspirin molecule, for the following structures? I have to generate a copy of the molecular structure of aspirin and then for each of the molecular features listed in (i) – (iii) have to produce a related structure...
67. ### Chemistry

what are the other chemistry forms present in the dichloromethane solution besides the normal neutral forms for benzoic acid and quinine? (benzoic acid,pKa 4.2; quinnie, pKa 8.5)
68. ### chemistry

Greg reacts 5.0 moles of hydrochloric acid(HCL)with 1.5 moles of barium hydroxide(Ba(OH)2).Which reagent is the limiting reagent, and which is in excess?If the reagent runs to completion,how many moles of barium chloride(BaCl2)will be produced? CAN SOMEONE PLEASE HELP ME....
69. ### English

Can you please check these sentences for me? Thank you very much. It is really urgent! 1) She was looking at the people sitting at the cafè while she was driving. 2) She was listening to music on her earphones while she was running in the park. 3) She was looking at a mobile ...
70. ### chemistry

What is the concentration of the Mg2 ion in solution when [CO3-2] = 0.25M given that the Ksp= 6.82 x 10-6 for the following reaction MgCO3-------->Mg +. CO32- Chemistry - DrBob222, Friday, November 11, 2011 at 5:34pm Ksp = (Mg^2+)(CO3^2-) Substitute 0.25M for CO3^2- and ...
71. ### soil chemistry

Can someone please help me answering this question regarding soil chemistry? A sandy soil has a CEC = 5 meq/100g and a K saturation = 6%. An alfalfa crop yields 5 ton/ac/yr at 3% K. Calculate initial exchangeable K and estimate final exchangeable K. Where did the additional K ...
72. ### math

in an examination, 31 candidate passed chemistry, 29 passed physics and 3 failed both subject. if 50 candidate sat for the examination, how many of them passed chemistry only?
73. ### Math

First student bought art, math and history books for \$72. a+m+h=72 Second student bought art, chemistry and history books for \$80. a+c+h=80 Third student bought chemistry, math and history books for \$61. c+m+h=61 Fourth student bought art, math and chemistry books for \$57. a+m...
74. ### Chemistry

3. A chemistry student makes up a 0.10 M solution of NaF(aq) and finds the pH to be 8.09. a. Explain why the presence of F- in this solution affects the pH. b. Write out the acid/base equilibrium equation for the reaction of F- with water. c. Use the measured pH value to solve...
75. ### Finance

4.A thirty year US treasury bond has a 4.0 percent interest rate.In contrast, a ten year Treasury bond has an interest rate of 2.5 percent. A maturity risk premium is estimated to be 0.2 percentage points for the longer maturity bond. Investors expect inflation to average 1.5 ...
76. ### chemistry

chemistry posted by Naomi today at 8:03pm. The material Magnesium Sulfate What mass of dry material would be needed to make an aqueous solution with a molality of 4 moles/kg solution ? What mass of water is needed? 4 (24.305+ 32.065+ (4 x 15.999)) =481.5 ?Not sure where to go ...
77. ### Science! URGENT

Bacteria can reproduce through asexual or sexual reproduction. Environmental conditions for a particular bacteria species are good and the bacteria are thriving. Which form of reproduction will the bacteria most likely use? A. The bacteria will most likely reproduce through ...
78. ### bio101

2. Find a media piece—article, video, presentation, song, or other—that recognizes the fundamental concepts of chemistry in biology. Include the link or reference citation for the piece and describe how it helped you better understand how fundamental concepts of chemistry ...
79. ### Chemistry

At what initial concentration would a solution of acetic acid (ka=1.8x10^-5) be 2% ionized? Thanks Responses Chemistry - DrBob222, Thursday, February 12, 2009 at 10:00pm Let's call acetic acid HAc. Then the ionization is HAc ==> H^+ + Ac^- We will call the initial concn of ...
80. ### chemistry

We had a Chemistry lab for buffer system, we used HCl and NAOH. We did a graph ( PH vs ml of HCL and NaOH, we told to estimate the buffer capacity using the graph. How to do this?
81. ### Chemistry

according to the bohr model of the hydrogen atom, what is the closest an electron can get to the nucleus? What is the farthest it can get from the nucleus? ( if the latter answer seems absurb, it might amuse you to know that it is the same value predicted by present-day ...
82. ### Biology---Urgent

14. Surface area is an important factor in limiting growth cell because a. the cell may become too large to remove enough wastes. b. materials can't enter the cell if it's too large c. the cell can burst if the membrane becomes too large d. waste products can't leave the cell ...
83. ### Chemistry

In what directions (on the periodic table) does atomic size increase? As you go down in a group, size increases, and as you go LEFT size increases. Size decreases as one goes right within a period. http://www.sparknotes.com/chemistry/fundamentals/atomicstructure/section3.rhtml...
84. ### science

What are 3 chemical properties of iron and 2 chemical properties of sodium? http://chemistry.allinfoabout.com/periodic/fe.html http://chemistry.allinfoabout.com/periodic/na.html Thanks. That helped a little.
85. ### English (URGENT) Please :'(

I have trouble understanding of this article and how to answer the questions given. I just started new to school in Toronto; I was living in Turkey for Years So I do please to take your time to look and examine my homework. I greatly appreciate your patience and time and ...
86. ### Chemistry

When someone buys fish at the fresh fish market, they should smell the fish to test for freshness, the less “fishy” the smell the fresher the fish. I am supposed to explain the source and chemistry, including reactions, structures, and names of the compounds, behind the ...
87. ### Physics URGENT!!!

A wheel has a radius of 3.5 m. How far (path length) does a point on the circumference travel if the wheel is rotated through an angle of 71.0°? B) A wheel has a radius of 3.5 m. How far (path length) does a point on the circumference travel if the wheel is rotated through an...
88. ### chemistry

how many grams of sodium carbonate are needed to prepare 0.250 L of an 0.100 M aqueous solution of sodium ions? well normally you go moles=grams/molar mass than M= moles/L but when looking for grams? what do you do........multiple .250 by .100 than divide by the molar mass of ...
89. ### Biology URGENT

Where can i find the Scientific Name of the Phyla/class of Eubacteria, Cyanobacteria, and Prochlorbacteria? Since this is not my area of expertise, I searched Google under the key words "Eubacteria phylum" to get these possible sources: (Broken Link Removed) (Broken Link ...
90. ### MATH

Please help me with these problems. Work and answer is appreciated! :) thanks. 1. Find on the interval theta is greater than or equal to 0 and less than 2pi; then find the general solution: 5tantheta+1=-2.89 16cos^2theta-6=3 6sin^2theta+sintheta=2 costheta=.84 2tanx=7 2.Find ...

A local college cafeteria has a self-service soft ice-cream machine. The cafeteria provides bowls that can hold up to 16 ounces of ice-cream. The food service manager is interested in comparing the average amount of ice-cream dispensed by male students to the average amount ...
92. ### Chemistry

Could someone please check my Chemistry homework? The molecular formula for cisplatin, a chemotherapy agent, is PtCl2(NH3)2 (The numbers are all supposed to be subscripts) 1. What is the molar mass of cisplatin? Ans: 300.06 g/mol 2. How many moles of hydrogen atoms are in one ...
93. ### chemistry

So I have to make a green cleaner for a project in chemistry. I think my ingredients should be: vinegar, salt, water, and lemon juice. But I don't know how I would write that exactly as a chemical formula. How could I write a chemical equation if I have 4 reactants? I can try ...
94. ### chemistry

In a chemistry experiment, a student measures the density of iridium (Ir) metal as 21.52 g/cm3. The actual density of Ir metal is 22.65 g/cm3. What is the percent error of the student's measurement?
95. ### Chemistry

A flask of known volume was filled with air to a pressure of 3.6atm. This flask was then attached to an evacuated flask of known volume and the air was allowed to expand into the flask. The final pressure of the air (in both flasks) was 2.7atm and the volume of the second ...
96. ### chemistry

Here is a reaction: 2Al+3H2SO4--->Al2(SO4)+3H2 determine the oxidation numbers of each element in both the rectants and the products of this oxidation reduction reaction of aluminum and sulfuric acid? Which element is oxidized in this reaction? Which element is rduced in ...