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December 18, 2014

Search: How much energy is needed to ionize a hydrogen atom in the n = 5 state

Number of results: 48,682

chemistry
How much ammonia is produced if 1.80 m3 of hydrogen reacts with 0.5m3 of nitrogen? Also state which reagent is in excess and by how much? Question is related to the Haber process. Please can anyone answer this for me by 02 July 2010. Thanx
June 30, 2010 by Anonymous

science
what is the calculation of the ground state energy of the O^7+ hydrogen-like ion. can your answer be in Ve and to an approriate number of significant figures please.
April 26, 2009 by mathew -b

Chemistry
Energy Level Transfer of Hydrogen's electron. For each line, determine the prinicpal energy level to which hydrogen's electron was excited. When the electron fell to the 2nd level, energy was released corresponding to each of the lines. E= 2.179X10-18 (1/n2 lo- 1/n2 hi). The ...
November 7, 2012 by Melody

chemistry
500 grams of water at 0 degrees C was heated to a boiling in a large pot. how much energy was needed? what was the temperature change and Heat energy
May 2, 2011 by amanda

physics/chem
Calculate the number of coulombs of positive charge in 261 cm3 of (neutral) water. (Hint: A hydrogen atom contains one proton; an oxygen atom contains eight protons.)
March 31, 2008 by dave

Chemistry
If water is synthesized how much hydrogen would be needed to make 10.0 grams?
February 10, 2012 by Cathy

Physics
Lithium is the atom which has three protons in its nucleus and three electrons circling the nucleus.(it usuallly has 3 nuetrons as well,but they r not important in this problem.)Two of the electrons circle the nucleus at a distance 1.8* 10^-11 m (app.)The third electron is ...
February 7, 2008 by jenish

Physics
In the hydrogen atom the radius of orbit B is sixteen times greater than the radius of orbit A. The total energy of the electron in orbit A is -0.378 eV. What is the total energy of the electron in orbit B?
April 5, 2012 by DCM

chemistry help !!!!!!!!!!!!!!!!
a)A N6+ ion in its ground state absorbs an X-ray photon of energy 2.0000 keV. Explain what happens to the ion and why. b)Explain why the nitrogen ion N6+ is a hydrogen-like ion. Assuming the ion is for the major stable isotope 14N, state which sub-atomic particles it contains ...
March 10, 2013 by john

Chemistry
why are the orbitals of the hydrogen atom described as probability maps? Why are the edges of the hydrogen orbitals sometimes drawn to appear "fuzzy"?
March 25, 2010 by student

Science
Why is the colour of the light emitted by an element in its gaseous state characteristic of the element? And why does hydrogen with only one electron have so many spectral lines? I have some idea but I need to clarify my understanding against someone else's view. I would be ...
February 6, 2007 by Lucy

Chemistry
How much ammonia is produced if 1.80 m3 of hydrogen reacts with 0.5m3 of nitrogen? Also state which reagent is in excess and by how much? Question is related to the Haber process. Please can anyone answer this for me by 02 July 2010. With all equations. Thanx
June 30, 2010 by Matt

Science
1) Why do scientists use models?(1point) Scientists use models to learn about things that are too small, too large, or to complex to observe directly. Scientists use models because doing so is always part of the scientific method. Scientists use models because they work ...
September 19, 2013 by Gabby

chemistry
Suppose a sample of hydrogen gas is excited to the n=5 level. As the atoms return to the ground state (Balmer series), they emit light. a. How many lines are there in the spectrum? b. Draw an energy-level diagram indicating theses transitions. c. Calculate the three lowest-...
January 22, 2011 by Maria

chem
one atom of silicon can properly be combined in a compound with A. one atom of chlorine B. two atoms of oxygen C. three atoms of hydrogen D. four atoms of calcium B. two atoms of oxygen (as in SiO2.. quartz and sand) Ther is also a compound SiO. It is used for optical coatings...
August 5, 2005 by alf

Physics
GIVEN: A monochromatic laser is exciting hydrogen atoms from the n=2 state to the n=5 state. A: What is the wavelength of the laser? *435 nm B: Eventually, all of the excited hydrogen atoms will emit photons until they fall back to the ground state. How many different ...
April 23, 2008 by Chelly

chemistry
In the Bohr model, which is the lowest energy state available for an electron? A. nth B. excited state C. first state D. ground state Im thinking the answer is c or d.
December 15, 2014 by Morgan

physics
A hydrogen nucleus has a radius of 1 x 10-15 m and the electron is about 5.3 x 10-11 m from the nucleus. Assume the hydrogen atom is a ball with a radius of about 5.3 x 10-11 m and the nucleus is a ball with a radius of 1 x 10-15 m. How much work (in electron volts) must be ...
April 24, 2008 by shanika

Chemistry
Posted on April 12. From the information below, identify element X. a. The wavelength of the radio waves sent by an FM station broadcasting at 97.1 MHz is 30.0 million (3.00 e7) times greater than the wavelength corresponding to the energy difference between a particular ...
April 18, 2007 by Gabriela

physics
Consider a circuit with an RL series with L=0.09 H and R=0.05 Ohm. At t=0 the circuit is connected to a battery which provides V0=12 V. (a)How long does it take to the current to equal a fraction 0.95 of the steady state current? (b) What is the energy stored (in Joules) in ...
April 9, 2013 by abdul rahman

physics
Consider a circuit with an RL series with L=0.09 H and R=0.05 Ohm. At t=0 the circuit is connected to a battery which provides V0=12 V. (a)How long does it take to the current to equal a fraction 0.95 of the steady state current? (b) What is the energy stored (in Joules) in ...
April 12, 2013 by dd

chemistry
A sodium atom when excited gives off two very specific wavelengths of visible light. What does this tell us about sodium? A. There are two principal electron transitions in sodium. B. There are two electrons in a sodium atom. C. A sodium atom has its electrons in two energy ...
December 12, 2014 by Morgan

Chem.
Three emission lines involving three energy levels in an atom occur at wavelengths x, 1.5x, and 3.0x nanometers. Which wavelength corresponds to the transition from the highest to the lowest of the three energy levels? Please help me, thank you very much for your time.
January 13, 2008 by Jady

Astronomy
One possible energy source for the mysterious object you've just discovered is the fusion of hydrogen to form carbon-12 (the most common and stable isotope of Carbon). Hydrogen has an atomic mass of 1.00794 u, while carbon has an atomic mass of 12.010 u. If you fuse Hydrogen ...
April 28, 2014 by qwerty

Chem
Consider a system of three molecules A, B, and C. Suppose that three units of energy can be distributed over the three atoms. Each atom can have no energy, one unit of energy, two units of energy, or all three units of energy. Assume that each of the ten possible arrangements ...
November 3, 2010 by John

CHEMISTRY
Consider a system of three molecules A, B, and C. Suppose that three units of energy can be distributed over the three atoms. Each atom can have no energy, one unit of energy, two units of energy, or all three units of energy. Assume that each of the ten possible arrangements ...
November 3, 2010 by John

Chem---DrBob222
Calculate the oxidation # for each atom in the molecule below. Can you help me with the rest. Thank you!!! H H H H / / / / H -- C ---C ===C ----N .. / / H H Group # # of E Oxidation # H 1 0 1 x 7 = 7 C 4 7 C 4 C 4 N 5 3 H atom attached to first C atom. 1 H atom to second C ...
September 18, 2014 by Layla

chem helpp!
Consider a system of three molecules A, B, and C. Suppose that three units of energy can be distributed over the three atoms. Each atom can have no energy, one unit of energy, two units of energy, or all three units of energy. Assume that each of the ten possible arrangements ...
November 3, 2010 by John

chemistry
1)nitrogen atom has atomic no 7 and mass no 14.hydrogen atom has atomic no 1 and mass no 1.what is no of protons and neutrons of ammonium ions
June 21, 2013 by vishal

annatomy
Calculate the osmolarity of a solution that contains 0.1 M urea, 0.2 M NaCl, and 0.5 M CaCl2. Assume urea does not ionize and NaCl and CaCl2 ionize completely
November 29, 2010 by russel

Chemistry
An electron ps from the 6th to te 3rd energy level in the hydrogen atom: a) calculate the wavelength b) calculate the frequency c) calculate te enrgy d) into which spectral series would the photon be grouped? (i really just need to formulas, then i could solve myself...)
May 23, 2011 by Ella

Chemistry
The hydrogen atomic emission spectrum includes a UV line with a wavelength of 92.3 nm. Is this line associated with a transition between different excited states or between an excited state and the ground state? What is the value of n1 of this transition? What is the ...
October 22, 2011 by Anonymous

chem
In a vehicle, H2 could be used in a fuel cell to generate energy. Hydrogen is not an energy source, but a means of transporting energy because the extraction of H2 from the logical source, H2O, takes as much energy as is returned when the gas is used. 2 H2O (l) → 2 H2 (g...
November 2, 2010 by Andrew

introductory technology
Question 1 1) state five operation that a vice can carry out 2)state the energy input and energy output of the following appliances a)electric iron b)electric kettle c)gas lamp d)ceiling fan e)radio set Question 2 1)list two common methods of cutting screw 2) the common things...
January 2, 2010 by jolomi skinn

Physics Homework
Consider problem U concerning the geosynchronous satellite of mass 50 kg. It orbits at a radius of 42,300 km with a speed of 3076 m/s. a) How much energy is needed to lift the satellite from the earth's surface (Re=6,370 km) up to that radius? b) How much kinetic energy does ...
October 20, 2013 by Eli Smith

Chemistry
1)Identify which concepts/topics you believe that you will need to apply to solve the problem below. Select all that apply. a)Covalent Bond Energy b)Ionic Bond Energy c)Single-electron Atom Ionization Energy d)Multi-electron Atom Ionization Energy e)Electronegativity f)...
November 18, 2012 by selly

chemistry
For the reaction, shown below, determine which statements are True and which are False. 3Fe(s) + Cr2O72-(aq) +14H+(aq) → 3Fe2+(aq) + 2Cr3+(aq) + 7H2O(l) ξo=1.77V 1. The oxidizing agent is dichromate (Cr2O72-). 2. The iron half-reaction takes place in an acidic ...
May 2, 2014 by bekah

Science
What is the radius in nm of the electron orbit of a hydrogen atom for n=3? What is the radius in nm of the electron orbit of a hydrogen atom for n=4?
January 14, 2014 by Katie

physics
A water molecule consists of an oxygen atom with two hydrogen atoms bound to it. The bonds are .100nm in length and the angle between the two bonds is 106 degrees. Use the x-y axis shown and determine the location of the center of gracity of molecule. Consider the mass of an ...
January 25, 2007 by cyndi

Bio
1. An isotope is an atom of an element that varies in mass number due to variation in the number of: A. atoms. B. protons. C. neutrons. D. electrons. is it C 2, A covalent bond is: A. the attraction that one atom has for another atom. B. the attraction between two atoms, ...
July 10, 2013 by Amy

Chemistry
For fluoracetic acid the highest Boltzmann distribution is when the dihedral angle is at 0 degrees. However, going from chloro- to bromoacetic acid, an increasing dip in the Boltzmann distribution occurs at 0 degrees. What is responsible for this "dip?" (HINT: look at how the...
July 12, 2010 by Anth

Physics
Q1: Find the frequency of revolution of the electron in the classical model of the hydrogen atom.In what region of the spectrum are electromagnetic waves of this frequency?? Q2:A beam of 13.o electrons is used to bombared gaseous hydrogen.What series of wavelengths will be ...
June 3, 2014 by Shah Rukh

Physics
Question: The amount of internal energy needed to raise the temperature of .25 kg of water by 0.2 degrees Celsius is 209.3 J. How fast must a 0.25 kg baseball travel in order for its kinetic energy to equal this internal energy? KE = (.5)(m)(v^2) 209.3 J = (.5)(.25kg)(v^2) ...
February 15, 2010 by mike

science, chemestry
Identify which concepts/topics you believe that you will need to apply to solve the problem below. Select all that apply. Covalent Bond Energy Ionic Bond Energy Single-electron Atom Ionization Energy Multi-electron Atom Ionization Energy Electronegativity Limiting Reagent ...
November 18, 2012 by smile

Physics
A hydrogen atom is at the earth's surface. The electron and proton in the atom are separated by a distance of 5.29x10^-11m. What is the ratio of the magnitude of the electrical force exerted by the proton on the electron to the weight of the electron?
June 26, 2014 by jr

chemistry
do hydrogen bonds form between methanol (CH3OH) molecules? no, because methanol does not contain fluorine or nitrogen atoms yes, because methanol has a hydrogen attached to an oxygen atom may vary depending on the temperature
March 1, 2012 by krystal

Physics
Supppose an atom has four distinct energy states. Assuming all transitions are possible, how many spectral lines can this atom produce? Answer with a number only.... ? have no idea
April 11, 2008 by Molly

ha
An atom emits a photon of wavelength 1.08 meters. What is the energy change occurring in the atom due to this emission? (Planck's constant is 6.626 10ȳ joule seconds, the speed of light is 2.998 10 m/s)
October 11, 2013 by gg

Chemistry+need help checking work
Using aervage atmoic masses for each of the following elements, calculate the mass, in amu (grams) A. 635 atoms of hydrogen ---> 1 mole of H = 1.01g = 6.022 x 10^23 atom 635 atom of H 1.01g/6.022 x 10^23 atom I got 1.06 x 10^-21 amu. I got that answer buying the "E" button ...
January 7, 2009 by Chopsticks

physics
The energy of the electron in the 2s state is -12.98 eV, the energy in the 3s state -10.84 eV. What is the wavelength of the absorbed photon?
April 26, 2011 by Tisha

Chemistry
Please help! How many moles of hydrogen are needed to triple the volume occupied by 0.25 mol of hydrogen, assuming no changes in pressure or temperature
May 25, 2011 by Michelle

physics
How much energy is produced when the sun converts one kg of hydrogen into helium?
March 9, 2010 by lisa

physics
The mass of a carbon atom is 2 x 10 ^ -26. What is the kinetic energy of a carbon atom moving with a speed of 500 m/s? What is the formula I would need?
November 30, 2009 by Julia

chemistry
The equation for the reaction between hydrogen gas and oxygen gas is: 2H2(g) + O2(g) ---> 2H2O(l) i) How much hydrogen will react with 8g of oxygen? ii) how much water will be formed when 6g of hydrogen react? i would appreciate your help.
October 17, 2010 by paul

chemistry
The equation for the reaction between hydrogen gas and oxygen gas is: 2H2(g) + O2(g) ---> 2H2O(l) i) How much hydrogen will react with 8g of oxygen? ii) how much water will be formed when 6g of hydrogen react? i would appreciate your help.
October 17, 2010 by paul

physics
An electron at ground state in the atom (-10.38eV)is struck by a passing electron with 7.00eV of energy. What is the velocity of the passing electron afrer the collision?
September 23, 2013 by sam

physics
An electron at ground state in the atom (-10.38eV)is struck by a passing electron with 7.00eV of energy. What is the velocity of the passing electron afrer the collision?
September 23, 2013 by sam

science
An atom emits a photon of wavelength 1.08 meters. What is the energy change occurring in the atom due to this emission? (Planck's constant is 6.626 10ȳ joule seconds, the speed of light is 2.998 10 m/s)
April 18, 2013 by Anonymous

chemistry
An atom emits a photon of wavelength 1.08 meters. What is the energy change occurring in the atom due to this emission? (Planck's constant is 6.626 10ȳ joule seconds, the speed of light is 2.998 10 m/s)
June 12, 2013 by Anonymous

Physics
With a 1220W toaster, how much electrical energy is needed to make a slice of toast (cooking time = 1.3 minute)? At 12.1 cents/kWh, how much does this cost? (You do not need to enter any units.)
September 13, 2014 by Joe

General Chemistry
How much energy in kJ is realeased to form one mole of Cd 116(isotope) from protons and neutrons if the atom has a mass of 115.90476amu.
May 8, 2010 by Chem

PHYSICS
The average kinetic energy of an atom in a monatomic ideal gas is given by KE=3/2kT, where k=1.38*10^-23J/K and T is the Kelvin temperature of the gas. Determine the de Broglie wavelength of a helium atom (mass=6.65*10^-27kg) that has the average kinetic energy at room ...
April 29, 2008 by Elaine

chemistry
Given the following equation: Mg(s)+2HCl(aq) goes to MgCl2(s)+H2(g) How many grams of hydrogen chloride (HCl) are needed to produce 200g of hydrogen H2?
January 17, 2011 by Jasmine

science
Hydrogen burns with blue flame.Oxygen support burning when two atoms of Hydrogen combines with one atom of oxygen forms water this water put off the flames why?
August 26, 2011 by duppala

Science
Atom building game board has 17 protons, 18 neutrons, and 18 electrons. *What is the atom that's represented on the game board. *What is the total charge on this atom? *What is the mass # of this atom? *What do you call an atom that different #'s of protons and neutrons? *What...
September 21, 2007 by Sonic

chemistry NEED HELP please
N2(g) + 3H2(g) ==> 2NH3(g) A. If 16.99 g of hydrogen is reacted at STP, volume of ammonia is produced? B. If 35.82 L of nitrogen is reacted at STP, what mass of hydrogen must also be reacted? C. At STP, what volume of hydrogen is needed to produce 70.9 L of ammonia; D. What...
May 10, 2011 by Danni

Biochemistry
ATP hydrolysis at pH 7.0 is accompanied by release of a hydrogen ion to the medium. if delta G note for this reactionis -30.5 kJ/mol, what is the free energy change for the same reaction with all component, including H+ at a standard state
October 6, 2010 by Help Pleasssssssse!!!

chemistry
just take H2O AND CH3CH2OH as example.why say that h2o can form two hydrogen bond per molecule but CH3CH2OH only one.i am confused as both of them also has two lone pairs per molecule,is it true that one hydrogen atom will result in only one hydrogen bond and two hydrogen bond...
June 17, 2013 by amper

Chemistry
Consider a system of three molecules A, B, and C. Suppose that three units of energy can be distributed over the three atoms. Each atom can have no energy, one unit of energy, two units of energy, or all three units of energy. Assume that each of the ten possible arrangements ...
October 23, 2007 by Richard

Science
A car's engine is only 12% efficient at converting chemical energy in gasoline into mechanical energy. If it takes 1.8 x 104 N of force to keep the car moving at a constant speed of 21 m/s, how much chemical energy would be needed to move the car a distance of 450 m at this ...
July 18, 2012 by Bob

Science
A car's engine is only 12% efficient at converting chemical energy in gasoline into mechanical energy. If it takes 1.8 x 104 N of force to keep the car moving at a constant speed of 21 m/s, how much chemical energy would be needed to move the car a distance of 450 m at this ...
July 18, 2012 by Rob

Physics
A car's engine is only 12% efficient at converting chemical energy in gasoline into mechanical energy. If it takes 1.8 x 104 N of force to keep the car moving at a constant speed of 21 m/s, how much chemical energy would be needed to move the car a distance of 450 m at this ...
May 4, 2014 by Lily

Physics
Describe the Bohr model of the atom. What is de Broglie's key idea (involving matter waves) that makes the Bohr atom have discrete energy levels?
November 16, 2009 by Lauren

mojo
A hydrogen atom is in its elevnth excited state, n = 12. Using the Bohr model of hydrogen, find the linear momentum. You want to solve for the electron velocity and multiply that by the electrn mass. There are many ways to do this. One would be to get the radius of the orbit ...
August 20, 2007 by physics

phisic
(a) One such reaction fuses two nuclei of carbon-12 (12/6C ) to form an atom of neon (20/10Ne ) with the emission of an α-particle. Write an equation for this process, indicating the atomic number and mass number of each of the products in the usual way. (b) Another ...
April 20, 2013 by john ergent help pleaseeeeeeeeeeeeeeeeeee?

science
Explain the relationship of the temperature of a substance during a change of state and the amount of thermal energy.Be sure to include information regarding change of state, absorption and realising of energy, and graph of thermal energy versus the temperature
September 6, 2007 by bah

chemistry
How much energy is needed to melt 25.4 grams od I2?
April 21, 2014 by jordan

Physics Homework
Consider problem U concerning the geosynchronous satellite of mass 50 kg. It orbits at a radius of 42,300 km with a speed of 3076 m/s. a) How much energy is needed to lift the satellite from the earth's surface (Re=6,370 km) up to that radius? b) How much kinetic energy does ...
October 20, 2013 by Eli Smith

Chem Help please
Consider a system of 3 molecules, A, B, and C. Suppose the 3 units of energy can be distributed over the three atoms where each atom can have no energy, one unit, two units or 3 units of energy. Assume each of the 10 possible arrangements is equally probable. What's ...
November 5, 2010 by Melissa

CHEM. help please
Consider a system of 3 molecules, A, B, and C. Suppose the 3 units of energy can be distributed over the three atoms where each atom can have no energy, one unit, two units or 3 units of energy. Assume each of the 10 possible arrangements is equally probable. What's ...
November 5, 2010 by Melissa

science help?
(a) One such reaction fuses two nuclei of carbon-12 ( 6 12C ) to form an atom of neon ( 10 20Ne ) with the emission of an α-particle. Write an equation for this process, indicating the atomic number and mass number of each of the products in the usual way. (b) Another ...
March 18, 2013 by sam

chemistry
For an atom of sulfur, which electron would require the least amount of energy to remove from the atom? A. 3s2 B. 1s1 C. 3p1 D. 3p4 I think the answer is c or d, preferring d. What would you go with?
December 15, 2014 by Morgan

chemistry
10. If the calcium oxide were obtained by the heating of calcium hydroxide, how much hydroxide would be needed to obtain the 15.0 g? 11. If the 15.0 g of calcium oxide in the above problems were allowed to react with water, what amount of calcium hydroxide would be produced? ...
December 13, 2012 by greg

Chemistry
It takes 208.4 kJ of energy to remove 1 mole of electrons from 1 mole of atoms on the surface of rubidium metal. How much energy does it take to remove a single electron from an atom on the surface of solid rubidium in Joules? What is the maximum wavelength of light capable of...
October 30, 2011 by franz

Physics (please help!)
1000 dust particles are trapped on a surface. There are two energy levels the particles can be in: absorbed on the surface in a zero energy state, or excited with energy E1. At a certain temperature T0, the particles are in thermal equilibrium, and 20 % of the particles are in...
August 5, 2013 by Anonymous

science
how much energy is needed to heat 3kg of aluminium from 21 oC to 50 oC?
September 4, 2009 by Curtis

Chemistry
How much energy is needed to melt a 30.5 g ice cube?
February 23, 2010 by Christopher

chemisty
How much energy is needed to melt a 30.5 g ice cube?
February 23, 2010 by Christopher

physics
how much energy is needed to heat 50 grams of ethanol
July 21, 2010 by sas

chemistry
if 150g of Ca(OH)2 is reacted with excess H2, how much energy will be needed?
January 9, 2011 by Vilika

chemistry
how much energy is needed to melt 25.4 g of I2 if enthalpy fusion of I2 is 61.7 J/g
March 8, 2012 by Anonymous

Physics
Consider problem U concerning the geosynchronous satellite of mass 50 kg. It orbits at a radius of 42,300 km with a speed of 3076 m/s. a) How much energy is needed to lift the satellite from the earth's surface (Re=6,370 km) up to that radius? b) How much kinetic energy does ...
June 17, 2014 by Rahul

Physics
Consider problem U concerning the geosynchronous satellite of mass 50 kg. It orbits at a radius of 42,300 km with a speed of 3076 m/s. a) How much energy is needed to lift the satellite from the earth's surface (Re=6,370 km) up to that radius? b) How much kinetic energy does ...
June 18, 2014 by Angel Mercado

Science
Hello van some one show me how to draw a dot and cross diagramm for 1 lithium atom and 1 fluorine atom(Lif) and also a diagram for 1 magnesium atom and 1 oxygen atom (MgO) Thankyou Paul.
March 28, 2011 by Paul

physics
1.A spherical bowl(R = 20 cm) contains water(n = 1.33) and your pet gold fish who, is swimming 15 cm from the centre of the bowl. You however are 35.0 cm from the edge of the bowl-outside, of course. Describe the image your fish sees. 2.The hydrogen atom consists of a proton ...
May 22, 2009 by Sandhya

chemistry
Assign an oxidation state to each atom in each of the following compounds. 1) Fe(CN)3 i know Fe= +3 but how do i find the oxidation state for C and N? does CN have a normal over all charge?
May 5, 2011 by Samantha

Probability
Consider a system of three molecules A, B, and C. Suppose that three units of energy can be distributed over the three atoms. Each atom can have no energy, one unit of energy, two units of energy, or all three units of energy. Assume that each of the ten possible arrangements ...
October 22, 2007 by Richard

physics
An electron and a proton are initially very far apart (effectively an infinite distance apart). They are then brought together to form a hydrogen atom, in which the electron orbits the proton at an average distance of 5.40 10-11 m. What is EPEfinal - EPEinitial, which is the ...
February 1, 2013 by abby

chemistry
1.what is meant by atomic number of an element? 2.the mass number of an element is 18,it contains 7 electrons.what is the number of protons and neutrons in it?what is the atomic number of the element? 3.an element has an atomic number of 11 and its mass number is 23?what is ...
May 4, 2012 by pooja

science- chemistry
How much energy in kilojoules is needed to heat 5.00 g of ice from -10.0 C to 30.0 C ?
December 7, 2010 by allie

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