# Posts by Maria

Total # Posts: 2,003

**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

**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?

**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 ...

**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?

**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?

**College algebra**

simplify by removing factors of 1 n^2-9/(n+3)^2

**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?

**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?

**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?

**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?

**chemistry**

determine the value of x for the following reaction: 4C + S8-> 4CS2 3.2 mol S8 yield x mol CS2

**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

**math**

y=2x-5 shifted down one

**math**

how do you change a linear equation to make the graph steeper?

**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?

**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.

**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.

**chemistry**

which is the symbol for the following monatomic ion? 8 protons and 10 electrons

**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?

**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...

**chemistry**

Mercury has a density of 13.6 g/mL. What is the mass of 4.72 L of mercury?

**chemistry**

Mercury has a density of 13.6 g/mL. What is the mass of 4.72 L of mercury?

**chemistry**

Mercury has a density of 13.6 g/mL. What is the mas of 4.72 L of mercury?

**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?

**chemistry**

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

**chemistry**

balance the chemical equation: Al(OH)2-- Al^2+ +OH^-

**chemistry**

show that 1mg/L = 1g/m3

**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.

**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?

**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?

**chemistry**

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

**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)?

**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) ...

**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?

**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.

**World History**

How was the grenade developed to help the war effort?

**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, ...

**9th grade algebra**

input/output numbers. i need the relation. x-1 2 3 4 5 y-0 5 28 81 176

**statistics**

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

**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

**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

**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?

**Algrebra**

3u-ux/x=6y/x

**Math (algebra)**

(y-1)/2u+x=m what does "u" equal?

**Math (algebra)**

(x-u)/3=5-y what does "u" equal?

**math**

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

**math**

Write 6+6+6+6=24 as a multiplication sentence.

**math -fractions**

Five

**Science**

Can you answer my question please becaise I can not find my answer

**Math**

Alright thanks I get it now (: I guess I was just multiplying wrong.

**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?

**unscramble spanish words**

sandia

**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. ...

**physics**

phuthy sawal nae andy

**math**

(28-2 x9) with the power of 2 + 2x7

**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

**math**

it has 5 different of axis rotational symmetry

**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 ...

**Comm**

Personal finance classes can help you if you have difficulties making budgets. Looking for verb and verb tense

**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 ...

**physics**

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

**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.

**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?

**algebra**

(1-2i)(1+2i)

**Chemistry**

why do isomers have different properties? please give examples.

**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 ...

**trigonometry**

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

**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...

**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 ...

**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

**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 ...

**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 ...

**world history**

what is the process of ice fishing in the colonial times

**math**

which is greater half pennies or 0.05 how do you know

**earth**

which two rocks are primarily composed of a mineral that bubbles with acid?

**physics**

OMGG I NOEE UGHH

**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...

**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?

**math**

8q+6-2p=0 39=p-q what is the solution or ordered pair

**English**

OK thanks that helped a lot!

**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)...

**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?

**HELP! advanced algebra**

thanks dude!!!!!!

**I NEED SERIOUS HELP!**

WHY WILL NO ONE HELP ME!!!????!!???

**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 ...

**math**

96/288=x 100-x= pages left

**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 ...

**Algebra**

im guessing you gave up on me bob? :(

**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?

**physics**

0.15

**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 ...

**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

**american History**

I need help answering the rest of the question. Is this someething you can further assist me with?

**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 ...

**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 ...

**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. ...

**algebra**

h=23

**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 ...

**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.

**math 5TH GRADE**

fifth gades have the most students playing sports after school.