Chemistry - December 2007

a. alkali metals only
b.alkaline earth metals only
c. both alkali and alkaline earth metals
d.neither alkali nor alkaline earth metals

2007-12-30 08:21:51 · 1 answers · asked by Anonymous

I need a Hypothesis for ---- How can using baking soda and vinegar inflate a balloon??

2007-12-30 08:16:11 · 2 answers · asked by Anonymous

Please, can anybody tell me how to figure out the problems that my teacher gave to my class to review for an AP chemistry Test shes giving us a in a couple of days and I have no clue how to solve these problems.

The following problems are:

1) Calculate the molarity of C2H5OH in a water solution that is prepared by mixing 50 ml of C2H5OH with 100 ml of Hs0 at 20 degrees Celsius. The density of the C2H5OH is 0.789 g/ml at 20 degrees Celsius.

2)What is the molarity of a solution of 50 g of propanol (CH3CH2CH2OH) in 152 ml water, if the density of water is 1.0 g/ml.

3). A solution containing 296.6g of Mg(NO3)2 per liter has a density of 1.114 g/ml. The molarity of the solution is what?

2007-12-30 08:12:45 · 3 answers · asked by Tachi 1

a.beryllium
b.cesium
c.calcium
d.barium

PLEASE HELP?!?!

2007-12-30 08:11:58 · 5 answers · asked by Anonymous

Quick Question:

How many ml of 18.4 M H2SO4 are needed to prepare 600 ml of .10 M H2SO4?

2007-12-30 08:05:26 · 2 answers · asked by Tachi 1

if strong acid can dislove and burn material - even flesh - then what does strong alkaline do

2007-12-30 07:53:50 · 2 answers · asked by Anonymous

Please, can anybody tell me how to figure out the problems that my teacher gave to my class to review for an AP chemistry Test shes giving us a in a couple of days and I have no clue how to solve these problems.

The following problems are:

1) A solution of hydrogen peroxide is 30% H2O2 by mass and has a density of 1.11 g/cm3. What is the molarity, if even possible

2) Calculate the molarity of C2H5OH in a water solution that is prepared by mixing 50 ml of C2H5OH with 100 ml of Hs0 at 20 degrees Celsius. The density of the C2H5OH is 0.789 g/ml at 20 degrees Celsius.

3)What is the molarity of a solution of 50 g of propanol (CH3CH2CH2OH) in 152 ml water, if the density of water is 1.0 g/ml.

4). A solution containing 296.6g of Mg(NO3)2 per liter has a density of 1.114 g/ml. The molarity of the solution is what?

2007-12-30 07:47:43 · 3 answers · asked by Tachi 1

in chem. lab we scratched dents in the edge of a penny with a file and left it in hydrochloric acid overnight. the zinc reacted and left just the copper shell.
i think it's chemical but i need to explain more.

2007-12-30 07:21:00 · 2 answers · asked by kryzzal5 2

The thermite reaction, used for welding iron, is the reaction of Fe3O4 with Al.

8Al (s) + 3Fe3O4 (s) = 4Al2O3 (s) + 9Fe (s)
H = -3350jk/mol

Because this large amount of heat cannot be rapidly dissipated to the surroundings, the reacting mass may reach temperatures near 3000C. How much heat is released by the reaction of 23g of Al with 57.6g of Fe3O4.


Im lost here. I was told i needed to find the limiting reactant? why? overall im totally lost here.

thank you.

2007-12-30 07:09:56 · 2 answers · asked by senseless.student 1

2007-12-30 07:03:57 · 16 answers · asked by Anonymous

The specific heat of copper metal of .385J/gC and it is .128 J/gC for gold. Assume you place 100 g for each metal, originally at 25C, in a boiling water bath at 100C. If each metal takes up heat at the same rate (the number of joules of heat absorbed per minute is the same), which piece of metal reaches 100C first? explain?

Wouldn't both reach 100C at the same time because the question actually sayseach metal absorbs heat at the same rate??

Thanks

2007-12-30 06:46:59 · 3 answers · asked by senseless.student 1

can any once convert these measurments into atoms /molecules

3.50 moles K

0.573 moles NF3

62.5 moles CO2

7.90 *104 MOLES h20

& please convert these measurments into moles

56.7g C

5.67 g NF3

44.0 g CO2

8.43*10 g Ag

thank you!

2007-12-30 06:42:26 · 4 answers · asked by Gentiana B 1

What mass will a sample of ammonium carbonate have if it contains 8.50 x 10^27 atoms?

My equation looked like this: (8.50x10^27 atoms)(1 mole/6.02x 10^23 atoms)(96.1g/1mol) but my answer is wrong apparently but maybe its teachers error?

But her (teacher) equation looked like

(8.50x10^27atoms)(1molec/14atoms)(1mole/6.02x10^23)(96.1g/1mole)

I asked a question previously and I got the answer that atoms and molescules are the same thing so is she right going abouts converting atoms to molecules.

2007-12-30 06:38:57 · 9 answers · asked by Ge1st 1

Which requires more heat to warm from 25C to 85C, 60g of water or 95.5g of ethylene glycol (specific heat = 2.39J/gC

So i used q=mst for each

(60g)(60C)(4.18) = q = 15048

(95.5g)(60C)(2.39) = q = 13694.7

so from this would the answer have the lower q? enthylene glycol?

2007-12-30 06:33:11 · 2 answers · asked by senseless.student 1

Also, if you did split CO2 using heat, would the outcome be solid, liquid? When I say split I mean split it into carbon and oxygen.

2007-12-30 06:25:16 · 2 answers · asked by Anonymous

A 20 g piece of aluminum at 0C is dropped into a beaker of water. The temp of the water drops from 90C to 75C. What quantity of heat energy did the peice aluminum abosrb? The specific heat of aluminum is .902 J/gC.

to do this problem do you do this:

q=mst

q=(20g)(.902)(75-90)

?? Thanks.

2007-12-30 06:23:55 · 3 answers · asked by senseless.student 1

cu2+ + OH- = ?

and should there be parenthesis around the OH in the equation?

2007-12-30 06:16:41 · 4 answers · asked by Anonymous

ok i'm used to seeing the enthalpy cycle with 3 arrows for the alternative route ,why would it have four ,as in this following equation:

N2O4(g) -----------------> 2NO2 (g)

2007-12-30 06:10:40 · 1 answers · asked by pumakelmusa 2

2007-12-30 06:00:50 · 1 answers · asked by Anonymous

Why is an excess of concentrated HCl necessary?
And whys is it necessary for the concentrated HCl to be cold?
Why is solid NaHCO3 used instead of liquid NaHCO3?
Why should the alkyl halide be dried carefully with anhydrous CaCl2 before distillation?

2007-12-30 05:56:03 · 2 answers · asked by qwerty09 2

i need help with a chemistry research question. through what procedures can one find the volume of a drop of liquid or aqueous solution. i really need help with this.

2007-12-30 05:56:01 · 3 answers · asked by I luv Dr. McDreamy 1

2007-12-30 02:54:30 · 3 answers · asked by Claudine A 1

the question asks us to calculate (i) the number of moles of CO2 produced.. (ii) the no. of moles of water produced.. (iii) determine the molecular formula of X..

i noe how to do (i) and (ii) but how do u do (iii)? thanx

2007-12-30 01:16:22 · 1 answers · asked by Anonymous

it is machian used in lab and i want to know how does work .
How a spectrophotometer is used to meausuew the absorption of light?

2007-12-29 23:33:46 · 2 answers · asked by iran78uk 1

2007-12-29 23:00:48 · 3 answers · asked by witchycake 2

2007-12-29 22:20:49 · 1 answers · asked by Anonymous

2007-12-29 22:19:21 · 1 answers · asked by Anonymous

2007-12-29 22:10:05 · 2 answers · asked by Ahtisham 1

What is the mass of one mole of the following compounds?
i) H2SO4
ii) Al(OH)3

With working aswell please :)

2007-12-29 21:59:26 · 6 answers · asked by Anonymous

I was doing the January 2007 Paper (Unit 1) when I realised that I got a question wrong:

State the strongest intermolecular bond in each of the following:
HF
HCl
HBr
HI

I said HF is hydrogen bonding
and the rest are dipole-dipole forces.

The mark scheme said that HF was correct but HCl, HBr and HI were Van der Waals forces or dispersion forces or induced dipole forces. It clearly said "reject dipole-dipole forces"

I do not understand why?
1. Firstly note it said state the strongest intermolecular force.
2. Also dipole-dipole forces are a type of van der Waals, so how could they accept Van der Waals but not dipole-dipole forces.

Any help would be widely appreciated.

2007-12-29 21:38:07 · 2 answers · asked by yos_msn 2