hm :)

Use the following data to answer the questions:

Ka (H3PO4) = 7.5 x 10^(-3)

Ka (H2PO4^(-) ) = 6.2 x 10^(-8)

Ka (HPO4^(2-) ) = 4.8 x 10^(-13)

The Kb for H2PO4^(-) is?

Correct answer is 1.3 x 10^(-12), not sure how to work it out.

Question 2:

In a 5.2 M solution of H3PO4, the concentration of HPO4^(2-) is?

thanks :)

does anyone know the name.

the story is about a boy called dan, and he makes this list of all the things he wants to do but for some reason cant... which is related to the title of the book which i cant think of

he and his mum move to this old townhouse which i think she inherited, but they had to sell all the furniture because they had know money. anyways the attic of his townhouse it attached to the house next door where this teenage girl lives. he falls for the girl and tries his hardest to impress her etc.

him and his friend go to a social/party with this girl, who ends up getting very drunk, and he has to sneak her in the window. i know its vague but does anyone know it? pretty sure it was the first book the author wrote as well, and it was only released in about 2010

thanks guys :)

it was in a book im studying for literature. thanks :)

i have taken levlen ed for almost two months

on the brochure it says to take the pills with a full glass of water but is this really necessary? why?

is it any less effective when taken with just a sip?

and also would levlen be in effect by now?

thanks :)

(3x+1) / (x+1)(x^3+x)

can someone explain to me how to work these out?

these are the questions i have but if you use the same method for all then you only need to do one

thanks heaps :)

NOTE: where i put the numbers, imagine theyre in subscript like in a chemical formula

determine the amount (in mol) of hydrogen atoms in each of the following:

a) 14.8g of hydrogen nitrite ( HNO2 )

b) 35.0 kg of beryllium hydride ( BeH2 )

c) 100g of hexanol ( C6H13OH )

d) 0.977g of aluminium monohydrogen orthophosphate ( Al2(HPO4)3 )

:)

(1) y=2x^2 - 12

(2) 3(x-4)

the answers are

x=0, y=-12 and

x=3/2, y=-7 1/2

but i dont know how to get them

can anyone help me out? :)

ok i need to define the formula:

midpoint of a line = (x1+x2)/2 , (y1+y2)/2

so i pressed

MENU

ACTIONS

DEFINE

then

mt (x1,y1,x2,y2) = (x1+x2)/2 , (y1+y2)/2

and it said missing )

so im not sure whats wrong

can anyone help me out? thanks :)

ok the question is

z^2 - 2z + 3 = 0 (z^2 is z squared)

and i have to find z

the answer is z = + or - 2i

where i is the representation of an imaginary number

and apparently i have to use the quadratic formula but i dont know how to do it

can someone explain to me? thanks :)

i isnt a pronumeral - its an imaginary number representative

and i have nooooo idea of how it works

so could someone help me with this problem and maybe explain it to me a bit?

thanks :)

an electronic bank teller registered

$775 after it had counted 120 notes

and $975 after it had counted 160 notes

a) find a formula for the sum registered ($C) in terms of the number of notes (n) counted.

b) was there already a sum on the register when counting began?

c) if so, how much?

:)

(a / x+a) + (b / x-b) = (a+b / x+c)

how do i make x the subject?

for real numbers a and b,

a > b

if and only if

a - b > 0

use this to state the larger of:

a) 5 - 3√2 and 6√2 - 8

b) 2√6 - 3 and 7 - 2√6

can anyone help me? i have no idea how to approach this

i keep getting √26 as my answer and i dont know where i went wrong but the calculator (which we arent supposed to use) and the answers in the textbook say 5√2

√ is meant to be the square root sign by the way :)

as in t = etc

and btw a-t/b-t is a-t divided by (fraction) b-t

thanks guys :)

bronwyn walks one lap of an oval at 2.5 km/h and then jogs another 8 laps of the oval at 5 km/h

if it takes her 30 minutes in total, how long in metres is each lap?

i know the answer but i need help with how to work it out

thanks :)

a shopkeeper buys a crate of eggs at $1.50 per dozen

he buys another crate, containing 3 dozen more than the first crate, at $2.00 per dozen

he sells them all for $2.50 per dozen, and makes $15.00 profit

how many dozens were there in each of the crates?

i neeed help :| thanks

Two tanks contain equal amounts of water

They are connected by a pipe and 3000 litres of water is pumped from one tank to the other

One tank then contains 6 times as much water as the other

How many litres of water did each tank contain originally?

i already know the answer but can anyone explain to me how to do this because i really dont understand

its maths methods unit 1 btw :)

has anyone recently has their belly button pierced at hairhouse warehouse (australia)?

- how much did it cost

- did that include the jewellery

- were you happy with the piercing?

thanksss

and what do the drugs do to improve performance for

a) cycling

b) archery

c) shot put

d) sprinting