toocool

find the length of the curve

as y = integral 1 to x (squareroo t^2 - 1 dt

4< x <7

(< or equal to)

need help..thankss

an astronaut ages 3 years when traveling at 99% the speed of light to the star procyon and back. The space officials to great her on her return age

a. less than 3 yrs

b. 3 yrs

c. more than 3 yrs

please explain and show work...i have no idea on how to start this problem

thanks

why is the percent ionization smaller in the buffer than in 0.1 M and 0.01M acetic acid solutions?

the buffer was acetic acid-acetate buffer

in general, how does the percent ionization change with the dilution of a weak acid or a weak base? use a general Ka or Kb expression to explain.

what does it mean?..

as % ionization increases, the soln becomes more dilute..how can i use ka or kb to explain.thanks

is Kool-Aid hypotonic , isotonic, or hypertonic to 10% sucrose solution?

suppose you have a dialysis bag of 10% sucrose, and you put it into kOol Aid and let it immerse for 1 hour. After 1 hr, the bag was red inside. Does that mean that Kool Aid is Hypotonic, because it flow into the dialysis bag?

A reaction is 50% complete in 35.0 min .

How long after its start will the reaction be 75% complete if it is zero order?

finding zero order for half life would be the [a]o / 2K

how can i find K?

A reaction is 50% complete in 35.0 min .

How long after its start will the reaction be 75% complete if it is zero order?

finding zero order for half life would be the [a]o / 2K

how can i find K?

A reaction is 50% complete in 35.0 min.

How long after its start will the reaction be 75% complete if it is first order?

no idea on how to start this except to find K

please help

The first-order reaction A --> product has t 1/2(aka half life) of 170 s.

What percent of a sample of remains unreacted 850 s after a reaction has been started?

i do not get what the question is asking

please explain

thanks

under an O2(g) pressure of 1.00 atm, 28.31 mL of O2(g) dissolves in 1.00 L H2O @ 25 C

what will be the molarity of O2 in the saturated solution at 25 C when O2 pressure is 3.72 atm? assume the solution volume reaimins at 1.00L ?

am i going to use PV=nrt and find n of O2? please help

0.105 M HNO2 which has a H ion and Nitrite ion concentration of 6.89 x 10^-3 M

what is the van't hoff factors?

how can i find i? having a hard time figuring it out

well i know van't hoff factor of HNO2 should be around 2.0 or something

please help

how many mL of glycerol, C3H8O3(D= 1.26 g/mL) must be added per kg of water to produce a solution with 4.95 mole % C3H8O3?

the part which i dont get is the 4.95 mole %...does that mean the mole fraction???

please explain and help me get started on how to find the mass of C3H8O3

thanks

MM of C3H8O3 is 92.0944 g/mol

please help thanks

how many grams of water would you add to 1.00 kg of 1.48 molality CH3OH to reduce molality to 1.00m Ch3OH

please help me figure out this problem..

i only got to this part..and i was wondering if im doing it right

1.00kg(1.48 mol/kg)(1kg/1.00 mol)(10^3 g/1kg)

is that it? or is there something else to it..

please explain

How much heat is required to raise the temperature of 210 g CH3OH from 18.0 C to 30.0 C and then vaporize it at 30.0 C? molar heat capacity of CH3OH is 81.1 J/mol k .

i dont know how to approach this question. please explain

q =mc (delta T)

how do i find q if it vaporize?

please help thanks

what constitutes a covalent bond according to valence bond theory?

please explain...

what is the valence bond theory?

b. valence bond theory works for a limited number of molecules, list two:

is it N2, and H2?

c. valence bond theory uses _____ orbitals to make bonds between atoms. the np orbitals are _____ apart imposing this bond angle in the molecule.

2p for the first one, what about the 2nd one?

d. hybrid orbitals arise from the _________ combination of _____ orbitals

i did not get an answer for this one...please explain and check my work..thanks

place in order of shortest to longest X-F bond for SiF4, N2F2, IF5

how can you find out which one is the shortest or the longest..? please explain..

How much energy(KJ) is required to remove all of the valence e- in one mol of silicon atoms?

i know i will have to start with 1 mole of Si

then where can i get the energy? please explain..

the very strong attraction of iron filings for a magnet is best explained by?

a. ionization energy

b. diamagnetism

c. electron affinity

d. ferromagnetism

e. paramagnetism

is it a? or am i wrong? please help..thanks

In the gas phase, the energy difference btween a cesium atom and its most stable ion is referred to as:

a. atomic energy

b. electron afinity

c. energy of vaporization

d. ionization energy

e. magnetic moment

would it be its ionization energy?

which of the following can never be isoelectronic species?

a. anions of 2 different elements

b. cations of 2 diff elements

c. an anion and a cation

d. an anion and an atom

e. atoms of 2 diff elements

what is an isoelectronic species?

please help..

the first ionization energy(IE1) for sulfur is less than the IE1 for phosphorus because;

a. hund's rule is violated

b. P has a p3 configuration

c. P is below S on the periodic table

d. 1st ionization energies decrease across a period

e. P is to the right of S on the periodic table

i do not think b, c, d, e is correct

so i am going towards a.

but im not sure why..so please explain

which of the following trends is followed by main group elements left to right across a period?

a. electronegativity decrease

b. atomic radius increases

c. electrons are held more weakly

d. attractive forces between the nuclues and outer electrons increases

e. none of these answer

a and b ..i know for sure it is not the correct answer..because electronegativity increases, and for b, atomic radius decreases..

i am aiming for D but not so sure.please help and explain..

What is the general relationship between electron affinity and atomic radius?

a. EA becomes more negative as radius increases

b. EA becomes more negative as raidus decreases

c. there is no relationship

d. EA becomes positive as radius decreases

e. EA becomes positive as radius increases

please help.. thanks