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August 30, 2015

Posts by Maria


Total # Posts: 1,683

chemistry
Calculate the energy (in eV) of the three lowest energy transitions in the Lyman series (the series that ends on n=1) of hydrogen. The wavelengths of these transitions are 121.6 nm, 102.6nm, and 97.3 nm. Draw an energy level diagram of these transitions
January 22, 2011

chemistry
A tube containing hydrogen atoms in the n=3 shell does not absorb visible light. The longest wavelength absorbed is 1875 nm. What state is the hydrogen atom in after absorbing a 1875 nm photon?
January 22, 2011

chemistry
We encounter a large number of waves every day without realizing it. One such source is radio waves. A typical frequency for radio transmission is 680 kHz. How much energy does one mole of radio waves carry? X rays used by doctors to view bones are much more energetic than ...
January 22, 2011

chemistry
Excited lithium atoms emit radiation at 670.8nm. a. calculate the frequency of this radiation. b. calculate the energy (in eV) of this radiation. c. What color is this radiation?
January 22, 2011

chemistry
Excited lithium atoms emit radiation at 670.8nm. a. calculate the frequency of this radiation. b. calculate the energy (in eV) of this radiation. c. What color is this radiation?
January 22, 2011

College algebra
simplify by removing factors of 1 n^2-9/(n+3)^2
January 21, 2011

chemistry
Copper reacts with sulfuric acid according to the following equation: 2H3SO4 + Cu-> CuSO4 + 2H2O + SO2 How many grams of sulfur dioxide are created by this reaction if 14.2 g of copper reacts with 18 g of sulfuric acid?
January 20, 2011

chemistry
Ammonia gas can be prepared by the reaction CaO(s) + 2NH4Cl(s) -> 2NH3(g) + H2O(g) + CaCl2(s) If 112 g CaO reacts with 224 g NH4Cl, how many moles of reactants and products are there when the reaction is complete?
January 20, 2011

chemistry
Copper reacts with sulfuric acid according to the following equation: 2H3SO4 + Cu-> CuSO4 + 2H2O + SO2 How many grams of sulfur dioxide are created by this reaction if 14.2 g of copper reacts with 18 g of sulfuric acid?
January 20, 2011

chemistry
Ammonia gas can be prepared by the reaction CaO(s) + 2NH4Cl(s) -> 2NH3(g) + H2O(g) + CaCl2(s) If 112 g CaO reacts with 224 g NH4Cl, how many moles of reactants and products are there when the reaction is complete?
January 20, 2011

chemistry
determine the value of x for the following reaction: 4C + S8-> 4CS2 3.2 mol S8 yield x mol CS2
January 20, 2011

chemistry
How many moles of oxygen can be obtained by the decomposition of 7.5 mol of reactant in the following reaction? 2KClO3 -> 2KCl + 3O2
January 19, 2011

math
y=2x-5 shifted down one
January 19, 2011

math
how do you change a linear equation to make the graph steeper?
January 19, 2011

chemistry
How many moles of gas does it take to occupy 120 L at a pressure of 233 kPa and a temperature of 340 K?
January 18, 2011

chemistry
The solubility of NaCl in water is 35.7 g NaCl/100 g H2O. Suppose that you have 500.0 g of NaCl. What is the minimum volume of water you would need to dissolve it all? The density of water is 1.0 g/mL.
January 17, 2011

chemistry
An explosive whose chemical formula is C3H6N6O6 produces water, carbon dioxide, and nitrogen gas when detonated in oxygen. write the chemical equation for the detonation reaction of this explosive.
January 17, 2011

chemistry
which is the symbol for the following monatomic ion? 8 protons and 10 electrons
January 17, 2011

chemistry
On average, earth's crust contains about 8.1% aluminum by mass. If a standard 12-ounce soft drink can contains approximately 15.0g of aluminum, how many cans could be made from one ton of the Earth's crust?
January 17, 2011

chemistry
Titanium is used in airplane bodies because it is strong and light. It has a density of 4.55 g/cm^3. If a cylinder of titanium is 7.75 cm long and has a mass of 153.2 g, calculate the diameter of the cylinder. (V=pi*r^2*h, where V is the volume of the cylinder, r is the radius...
January 17, 2011

chemistry
Mercury has a density of 13.6 g/mL. What is the mass of 4.72 L of mercury?
January 17, 2011

chemistry
Mercury has a density of 13.6 g/mL. What is the mass of 4.72 L of mercury?
January 17, 2011

chemistry
Mercury has a density of 13.6 g/mL. What is the mas of 4.72 L of mercury?
January 17, 2011

chemistry
A sample of crude oil has a density of 0.87g/mL. What volume in liters does a 3.6-kg sample of this oil occupy?
January 17, 2011

chemistry
No! It Al(OH) with the subindex of 2 ==> Al to the power+ plus OH with a negative sign on the top!
January 15, 2011

chemistry
balance the chemical equation: Al(OH)2-- Al^2+ +OH^-
January 15, 2011

chemistry
show that 1mg/L = 1g/m3
January 15, 2011

chemistry
you made up a standard solution of calcium sulfate (CaSO4). the temperature is 25C. you then add 5.00*10^-3 odium sulfate (Na2SO4). Calculate the concentrations of calcium and sulfate after equilibrium is reached? The pKs of CaSO4 is 4.58.
January 15, 2011

chemistry
The concentration of a chemical degrades in water according to order kinetics. the degradation constant is 0.2 day^-1. if the initial concentration is 100.0 mg/L, how many days are required for the concentration to reach 0.14 mg/L?
January 15, 2011

chemistry
the concentration of a chemical degrades in water according to order kinetics. the degradation constant is 0.2 day^-1. if the initial concentration is 100.0 mg/L, how may days are required for the concentration to reach 0.14 mg/L?
January 15, 2011

chemistry
if 200mg of HCl is added to water to achieve a final volume of 1.00 L, what is the final pH?
January 15, 2011

chemistry
a) 45.00g/L(1000mg/g)(1L/1000mL)=45mg/mL b)NaHCO3: 22.99+1+12+3(16)= 83.99g/mol prop. of Na (22.99/83.99)=0.54 c)? d)?
January 15, 2011

chemistry
A solution of sodium bicarbonate is prepared by adding 45.00g of sodium bicarbonate to a 1.00-L volumetric flask and adding distilled water until it reaches the 1.00-L mark. Calculate the concentration of sodium in units of: a) milligrams per liter b) molarity c) normality d) ...
January 15, 2011

Chemistry
A solution is made by dissolving 10.20 grams of glucose (C6H12O6) in 355 grams of water. What is the freezing-point depression of the solvent if the freezing point constant is -1.86 °C/m?
January 14, 2011

engineering
If faucet is dripping at a rate of one drop per second and each drop contains 0.150 milliliters. Calculate how much water will be lost in 1 year.
January 14, 2011

World History
How was the grenade developed to help the war effort?
January 13, 2011

PHI.: 103
what fallacy is this? I don't know what colleges are teaching these days! I have just received a letter of application from a young man who graduated from the state university last June. It was a wretched letter – badly written, with elementary errors in spelling, ...
January 13, 2011

9th grade alegbra
input/output numbers. i need the relation. x-1 2 3 4 5 y-0 5 28 81 176
January 11, 2011

statistics
from a group of six people two individuals are to be selected at random. How many possible selections are there?
January 8, 2011

Statistics
About how many participants are needed for 80% power in each of the following planned studies that will use a t test for dependent means with p < .05? Predicted Effect Size Tails (a) Medium Two (b) Large One (c) Small One
January 8, 2011

Statistics
About how many participants are needed for 80% power in each of the following planned studies that will use a t test for dependent means with p < .05? Predicted Effect Size Tails (a) Medium Two (b) Large One (c) Small One
January 8, 2011

Math
if a triangle has a perimeter of 50cm one side is double the length of the base and the second side is four less than three times the base how long is the base?
January 6, 2011

Algrebra
3u-ux/x=6y/x
January 6, 2011

Math (algebra)
(y-1)/2u+x=m what does "u" equal?
January 6, 2011

Math (algebra)
(x-u)/3=5-y what does "u" equal?
January 6, 2011

math
To multiply 5 by 3, you can find the product of 2 and 5 and the product of 1 and 5 and ________them.
January 6, 2011

math
Write 6+6+6+6=24 as a multiplication sentence.
January 6, 2011

Math
Alright thanks I get it now (: I guess I was just multiplying wrong.
January 2, 2011

Math
I don't get page 50 of algebra with pizzazz! Please help? 7) Kathy is 6 years younger than bill. 12 years ago bill was twice as old as Kathy was then. How old are they now?
January 2, 2011

unscramble spanish words
sandia
January 2, 2011

Garland High school
Suppose you must maintain a balance of least $500 in your checking account in order to have free checking. The current balance in your checking account is $635.27. Which inequality describes how much can write a check for a and still have free checking? A. 635.27>500-x B. ...
December 30, 2010

physics
phuthy sawal nae andy
December 29, 2010

math
(28-2 x9) with the power of 2 + 2x7
December 27, 2010

Algebra
How do I find the value of x such that the data set has the given mean. Example: 11,12,5,3,x; Mean=7.4
December 14, 2010

soc 120
1. The average height of members of the high scho etball team is six feet, three inches. Jerry is on the high school basketball team, so Jerry must be taller than six feet. The argument above is flawed because it confuses (Points : 1) Jerry with other members of the team the ...
December 12, 2010

Comm
Personal finance classes can help you if you have difficulties making budgets. Looking for verb and verb tense
December 11, 2010

physics
How much heat must be added to 0.55 kg of aluminum to change it from a solid at 180°C to a liquid at 660°C (its melting point)? The latent heat of fusion for aluminum is 4.0x10^5 J/kg. I understand the Equation Q=mc times change it T would that be .55 times 4.0 x 10^5 ...
December 10, 2010

physics
im wondering the same thing as leah cause i left mass in kg and it was marked wrong please help
December 10, 2010

physics
How much heat must be added to 0.55 kg of aluminum to change it from a solid at 180°C to a liquid at 660°C (its melting point)? The latent heat of fusion for aluminum is 4.0 105 J/kg.
December 10, 2010

4th grade
Jorge and Hector like to play marbles.Jorge had 7 more than four times the number of marbles that Hector had. Together they had 37 marbles. How many marbles did Jorge have?
December 9, 2010

algebra
(1-2i)(1+2i)
December 7, 2010

Chemistry
why do isomers have different properties? please give examples.
December 7, 2010

physics
Two identical containers are open at the top and are connected at the bottom via a tube of negligible volume and a valve which is closed. Both containers are filled initially to the same height of 1.00 m, one with water, the other with mercury, as the drawing indicates. The ...
December 6, 2010

trigonometry
find all degrees solutions to the following equation: sin (A + 50 degrees)=1/square root 2
December 5, 2010

physics
the negative charge distribution over the surface of two isolated spheres is depicted in the diagram. one of the spheres is made of copper and the other is of rubber. identify the sphere that depicts the charge distribution of copper and that of rubber. support the answer with...
December 1, 2010

physics
a positively charged light metal ball is suspended between two oppositely charged metal plates on an insulating thread. after being charged once. the plates are disconnected from the battery. describe the behavior of the ball. (the plates are not touching nothing and the ball ...
December 1, 2010

physics
what happens when light moves from a material with a lower index of refraction to another material with a higher index of refraction? please sho work and thank u
December 1, 2010

physics help
A 1240 N uniform beam is attached to a vertical wall at one end and is supported by a cable at the other end. A W = 1970 N crate hangs from the far end of the beamThe angle between the beam and the horizontal is 30 degrees upwards and the angle between the horizontal and the ...
November 27, 2010

english
I have to write a paragraph which sustains an ironic tone. I have two thesis that I want to write about. (1)Being organized shows a lack of creativity. (2) Reading is a waste of time. I want to write about the first one. Please tell me a way to write about it using Ironic ...
November 21, 2010

world history
what is the process of ice fishing in the colonial times
November 21, 2010

math
which is greater half pennies or 0.05 how do you know
November 17, 2010

earth
which two rocks are primarily composed of a mineral that bubbles with acid?
November 17, 2010

physics
OMGG I NOEE UGHH
November 17, 2010

English
uggh! sick of just getting sites! i need the real thing here! ... sorry to sound harsh but ive already looked at that site and it just doesnt help me...
November 16, 2010

English
Define Socialism. George Orwell doesnt think Socialism can work. WHY? How does he prove that it doesnt work by the way Animal farm ends?
November 16, 2010

math
8q+6-2p=0 39=p-q what is the solution or ordered pair
November 16, 2010

English
OK thanks that helped a lot!
November 16, 2010

English
We just got done reading Animal Farm, by George Orwell. I cant come up with enough facts for the following questions. How does Napoloen and the other pigs control the animals through fear and intimidation? so far i have by 1)by killing other animals right before their eyes 2)...
November 16, 2010

11th grade
SIMPLE! add 49 to the other side- 9x^2=49 Now take the square root of 49. I'm in 10th grade, isnt this easy? maybe im doing it wrong?
November 16, 2010

HELP! advanced algebra
thanks dude!!!!!!
November 14, 2010

I NEED SERIOUS HELP!
WHY WILL NO ONE HELP ME!!!????!!???
November 14, 2010

HELP! advanced algebra
A bakery is making whole-wheat bread and apple bran muffins. For each batch of bread they make $35 profit. For each batch of muffins they make $10 profit. The bread takes 4 hours to prepare and 1 hour to bake. The muffins take 0.5 hour to prepare and 0.5 hour to bake. The ...
November 14, 2010

math
96/288=x 100-x= pages left
November 14, 2010

Algebra 2
An appliance store manager is ordering chest and upright freezers. One chest freezer costs $250 and delivers a $40 profit. One upright freezer costs $400 and delivers a $60 profit. Based on previous sales, the manager expects to sell at least 100 freezers. Total prfit must be ...
November 14, 2010

Algebra
im guessing you gave up on me bob? :(
November 14, 2010

Math
James has an assigned seat for his flight to Denver.The seats on the plane are numbered 1-49.James's seat number is an odd number greater than 10 that is a factor of 100.What is his seat number for the flight?
November 8, 2010

physics
can you help me through this? A boat moves through a river at 7.0 m/s relative to the water, regardless of the boat's direction. If the water in the river is flowing at 3.5 m/s, how long does it take the boat to make a round trip consisting of a 250 m displacement ...
November 7, 2010

american History
I only had to answer that question if I didn't agree with imposing taxes. I am looking into the other questions now
November 4, 2010

american History
I need help answering the rest of the question. Is this someething you can further assist me with?
November 4, 2010

american History
Can someone help me please. I am having a hard time answering this question. Do you think Great Britain was justified in imposing taxes on the colonies following the French and Indian War? Or do you believe the colonists had legitimate grievances regarding the British policy ...
November 4, 2010

comparing fractions
In the fourth-grade class at Baker Elementary, 9 students are left-handed. The fifth grade has 7 left-handed students and the sixth grade has 6. The number of students in the fourth grade is 3 times the number of left-handed students in the class. The sixth grade has 3 more ...
November 3, 2010

comparing fractions
at Morris Elementarhy there are 45 students in each grade, four though six. In the fourth grade, 19 participate in sports after school. Two out of every six fifth grade play sports after schoo;. In the sixth-grade class, seven of every ten students are not playing sports. ...
November 3, 2010

algebra
h=23
November 2, 2010

Physics
A 23.0 kg block is initially at rest on a horizontal surface. A horizontal force of 80.0 N is required to set the block in motion. After it is in motion, a horizontal force of 57.0 N is required to keep the block moving with constant speed. Find the coefficients of static and ...
November 2, 2010

geometry
in triangle GHJ, k(2,3) is the midpoint of GH, l(4,1) is the midpoint of HJ and m(6,2) is the midpoint of GJ. Find the coordinates of G,H and J. can you please show me how to find this? i don't really understand how it would be done. thank you.
November 2, 2010

math 5TH GRADE
fifth gades have the most students playing sports after school.
November 2, 2010

math 5TH GRADE
at morris elementary there are 45 students in each grade, four though six. In the fourth grade, 19 participate in sports after school. Two out of every six fifth graders play sports after school. In the sixth-grade class, seven of every ten students are noot playing sports. ...
November 2, 2010

business
2. You are in the process of a major Spring Clean in your home/bedroom/office/garage. You have identified a variety of new and used items that you are no longer using. With summer around the corner you could use a bit more cash for a little vacation. Utilizing what you have ...
November 1, 2010

5th grade math
i have to write an algebraic expression for the following: jasmine has three times as many chores as her younger brother does.
November 1, 2010

3rd grade
mr.mcwilliams drove 76 miles on sunday and 43 miles Tuesday
October 31, 2010

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