Friday
April 18, 2014

Posts by Leo


Total # Posts: 348

Chemistry
so g/mol of oxygen has nothing to do with solving??

Chemistry
A closed container is filled with oxygen. The pressure in the container is 435kPa . What is the pressure in millimeters of mercury? (i know that 1atm=760mm Hg=101,325 Pa) How do I use this to solve for the question? so: 435kPa*101,325=44,076,375Pa, & O2 = 32g/mol & you must ha...

chemistry
Sulfuric acid dissolves aluminum metal according to the following reaction: 2Al(s) + 3H2SO4(aq) -> Al2(SO4)3(aq) + 3H2(g) Suppose you wanted to dissolve an aluminum block with a mass of 15.9g . A)What minimum mass of H2SO4 (in g) would you need? [***A=86.7g***] B)What mass ...

chemistry
ignore this question

chemistry
For each of the following acid-base reactions, calculate the mass (in grams) of each acid necessary to completely react with and neutralize 3.60g of the base. 2HNO_3(aq) + Ca(OH)2(aq) -> 2H_2O(l) + Ca(NO_3)2(aq) H_2SO_4(aq) + 2KOH(aq) -> 2H_2O(l) + K_2SO_4(aq) how do i d...

Chemistry
thank you.

Chemistry
ok...so I took 30,000g * 1/120.913g/mol = 248.1122g. Then I went: 248.1122g * 70.906g/mol & got: 17592g = 18kg. Does this look correct? should I carry it through to the rest?

Chemistry
How many kilograms of chlorine are in 30kg of each of the following chlorofluorocarbons (CFC's)? CF2Cl2 -in kg's; CFCl3 -in kg's; C2F3Cl3 -in kg's?

chemistry
how many oxygen atoms are in 1.60g of quartz - SiO2? how do you figure out atoms to grams and visa versa? the weight of 1 SiO2=60.0848g/mol. please help

chem
Question: The American Dental Association recommends that an adult female should consume 3.0mg of fluoride (F-) per day to prevent tooth decay. If the fluoride is consumed as sodium fluoride (45.24% F), what amount of sodium fluoride contains the recommended amount of fluoride...

computer programs
I have a problem just getting started on writing pseudocode or a program for the following problem: A worm is moving toward an apple. each time it moves, the worm cuts the distance between itself and th eapple by its own body length until the worm is close enough to enter the ...

grammar - showed versus shown
Which is the following sentences is grammatically correct? "She had shown me so much about love." "She had showed me so much about love." Thanks, Leo (webmaster)

womens studies
The word "ranking" suggests hierarchy: first rank, second rank, etc. The first rank is "higher" than the second rank. Therefore gender ranking implies one sex is higher or better than the other.

iphone
how cool is the iphone

Algebra 1
You should set up some formulas using x and y, x being the smaller number and y being the larger.

Algebra 1
First, multiply both sides of the first equation by negative one. Then, add the two equations together. This will cancel the y's and you can solve for x.

math
Hint: combine two two's so you have a 22 in the equation

economics
In economics, ineslasticity is the opposite of elasticity. This article may help you: http://en.wikipedia.org/wiki/Elasticity_(economics)

???
I optimized the forum's pages so that archived pages load faster. Also, I optimized individual messages so that they load faster and use up less disk space.

???
I am working on the database now :-)

time management
As I spend more and more time working, I spend less time with family and friends. However, my career and financial success are important to me. How do I balance the time I spend making money versus time I spend with people? What are some critical questions I may want to ask my...

Funny
You are correct. I am working to restore this.

Literature
I am currently working on restoring the database. Thanks, Leo

Math
uh oh if pencils cost 20 cents and pens cost 30 cents each find the cost of the following items number 36 has r pens and p pencils

MATH
Isopropyl alcohol, C3H8O, is used in rubbing alcohol mixture. Alcohol on the skin cools by evaporation. How much heat(in kJ) is absorbred by the alcohol of 2.25g EVAPORATED? THE HEAT VAPORIZATION OF Isopropyl alcohol is 42.1 kJ/MOL Compute the number of moles of C3H8O that cor...

if you're in the mood for riddles
The riddle forum is back up: http://www.jiskha.com/net_riddle There are some truly clever riddles being posted. The following is one of my favorites. Try not to scroll down because then you'll see the answer(s): http://www.jiskha.com/net_riddle/display.cgi?id=1169785254

new description for jiskha.com
The new meta description for jiskha.com is: Students get free homework help from teachers and experts on message boards and chat rooms. Website also features educational articles in math, science, social studies and literature. It will probably take Google a couple weeks to up...

description for Jiskha.com
A few of you have noted that Google's description of jiskha.com is ineffective on the search results. It currently reads: ----- Articles, games, humor and puzzles for many school areas including art, computers, English, foreign languages, health, home economics, mathematic...

Econ
What effect do lifting of price controls have on inflation in the long run? I need some ideas... I think inflation will eventually be under control in the long run, but i don't know what factors will cause that. Good tough question. Take a shot. I would think that lifting ...

Inflation
What long term effect do lifting of price controls have on inflation? This is a debatable issue. What does your book say? What do you think? Will inflation increase in the short run but then eventually decrease because when prices are too high, nobody is willing to buy?

trigonometry
Hint: The total of angle measurements inside any pentagon is the same. Hint: Look up the mathematical definition of an arithmetic sequence. IF THE MEASURES OF THE ANGLES OF A PENTAGON FORM AN ARITHMETIC SEQUENCE, WHAT ARE THE GREATEST AND LEAST MEASURES EACH ANGLE CAN HAVE? Th...

how to sketch a graph of..
Local minimum and local maximum imply that the function approaches negative and positive infinite at opposite sides of the graph. Local minimum (1,1) and local maximum (3,3) means the slope of the function is 0 at these points. Thank you so much. So 1)when the local minima is ...

school supplies
We just added a number of articles: http://www.jiskha.com/school_supplies This is one of my favorites: http://www.jiskha.com/school_supplies/staples.html Very nice!! =)

new forum up and running
The new forum is live. No more random error messages. Much faster searches, sorts and queries. Have a nice day. Thank you, Leo! The new forum is great!

one-third done with new forum
I worked on the new forum all day yesterday. It should be done by the end of tomorrow. There won't be any visual changes, but the forum should load even faster. Also, that silly random error message will stop occuring. Wonderful! Keep up the good work. DAG We ALL appreciat...

random error messages
Sometimes when posting a new message, a software error will occur with an "unable to post" warning. Right now I am working on fixing this error message once and for all. In the meantime, if you get this message, hit refresh on your browser to try to post the message ...

message board threads
As you may have noticed, an entire thread can now be viewed by accessing the original message. I think this is great for students, and this may enhance search engine rankings. If anyone has serious objections to this, please let me know. Thanks, Leo I think it's wonderful!...

open-ended formatting tags no longer an issue
If you forget to end your bold or italic tags, this is no longer an issue. All formatting tags are terminated at the end of each post. Tags currently allowed for anyone to use are b, i, u, sup and sub. example It is still good practice, however, to pair each opening tag with a...

I think we're doing something right
I noticed a few things: 1. when I search for homework help on Google, we're #10 (page 1)! 2. We received so many homework questions yesterday that page 1 and 2, and half of 3, was filled up with questions from Thursday. 3. 99% of the students who post are receiving GREAT h...

subscripts and superscripts enabled
Examples: The water molecule: H20 Quadratic: ax2 + bx + c = 0 Just like you would use the b tag for bold or the i tag for italic, use the sub and sup tags for subscript and superscript. that's great...but what do you mean "b tag" and "i tag" ?? the b ta...

how can we improve jiskha.com?
How can we improve jiskha.com? Any ideas for improvement are welcome. Thanks! Perhaps separating the subject areas. The subject area categories could be fairly general: English, including how to research Mathematics/economics Sciences Social studies/history Foreign languages A...

search box on jiskha.com
The search box at the top of this page now searches the entire jiskha.com forum in real time. http://www.jiskha.com/search/search.cgi?query=apples Nice. very nice.

5th grade math
what is the least common multiple The least common multiple is the lowest possible number that has both numbers for a factor. For instance, if you are asked to find the LCM for 4 and 8, the LCM would be 8 because it is divisible by both 4 and 8. If you were given 3 and 4, the ...

grammar
Does the following sentence contain any grammatical errors? Those are the kinds of people whom I will never talk to. Thanks, Leo Although it ends with a preposition, which some purists consider poor form, I see nothing wrong with the sentence. It also used "whom" cor...

homework help ranking
When I search for homework help on google from my computer, jiskha is ranked at #14. What is jiskha ranked on your computer? Thanks. Jiskha came in 12th on my computer. About 14 with or without " " Probably because of lower use during summer? 14th here -- and I think...

#2 on msn
I just noticed that if you search for homework help on m.s.n, we're number 2. ... and #8 on Google! =) # 4 on Yahoo And #1 with me. For a couple weeks now, if I search for homework help on my own connection, jiskha is ranked at #11 or #12. But if I go to the library, jiskh...

new data type for forum
Currently the forum uses hash maps which becomes extremely complex and prone to glitches as the number of posts approaches 10,000. I have determined that one solution would be to use linked lists instead of hashes. In fact, linked lists, also known as threads, is what most for...

annual salary
What is the formula to determine someone's annual salary given only the hourly wage? For example, if someone works full time for $20 per hour, how much does he earn in a year? A friend of mine told me the formula before; it's really simple. I just forgot it. Thanks! If...

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