Chemistry - March 2007

i want to know because i have a science project and its about silver... i need to list down like the atomic number from the periodic table and stuff i also need tro figure out how much dose a chunk of sivler ore is, soooo any one out there plz help meee....! ='{

2007-03-21 12:52:57 · 3 answers · asked by Chanel babe 2

the complete combustion of 3.0g of a food produces enought heat to raise the tempature of 300g of water from 20C to 75C. Assuming no heat loss what is the energy contect for the food expressed in Calories/grams?

EXPLAIN YOUR ANSWER!

2007-03-21 12:39:16 · 4 answers · asked by William R 1

as compound go from solid to liquid to gas how to enegry and entropy change?

both energy and entropy decrease
both energy and entropy increase
energy increases entropy decreases
energy decreases and entropy increases

2007-03-21 12:28:15 · 1 answers · asked by William R 1

which of the following gaseous atoms is expected to have the largest volume?
a. Sr +2
b. Sr
c. Be
d. Ca
E. Be+2

Why? what is the different between Sr. and Sr+2?
thank you

2007-03-21 12:26:49 · 3 answers · asked by carla 2

metalloid?

2007-03-21 12:11:49 · 1 answers · asked by Fishaay™ 2

im a 8th grader and i know what is aionic bond ijust dont know how to make it as a model. does anybody know? im using marshmellows and toothpicks.

2007-03-21 12:01:54 · 3 answers · asked by Georgie G 2

2007-03-21 11:53:05 · 2 answers · asked by Anonymous

can some one pick a question and answer it.[[or more]]
here i go:
1)A hot dog is cooked....is that a physicall change or a chemical change and y?

2)salad dresing and mayo r being mixed....physical oor chemical change...y?

3)water boiling?physical or chemical....Y?

2007-03-21 11:44:01 · 2 answers · asked by Fishaay™ 2

Consider the following equation for the vaporization of water:
H20 (l) <=> H20(g) (triangular sign) H= +40.65kJ/mol at 100 celsius

a. is the forward reaction exothermic or endothermic? exothermic
b. does the entalpy factor favor the forward or reverse reaction? forward
c. does the entropy factor favor the formard or reverse reaction? i dont get this one but i would say reverse

2007-03-21 11:06:02 · 1 answers · asked by Ballerina 5

and its absolute temperature is decreased by one-half. What is the final volume of the gas?


.. please help! i think you have to use stp? i dont know .. im so lost! please help! oh and i know the correct answer is .. 9.0 L
thanks in advance for any help!

2007-03-21 10:51:43 · 2 answers · asked by M 3

2007-03-21 10:50:43 · 4 answers · asked by Valin 2

2007-03-21 10:49:17 · 3 answers · asked by elchebib 1

2007-03-21 10:36:54 · 1 answers · asked by blessing 1

2007-03-21 10:34:05 · 2 answers · asked by elchebib 1

100.0 mL of a solution of quinine contains 170.0 x 10-3 mol of quinine.
a) If this is titrated with 0.200 M HCl, what is the pH half-way to the stoichiometric point ?

Quinine is monobasic with Kb = 7.90 x 10-6

b) What is the pH at the stoichiometric point ?

2007-03-21 10:31:27 · 2 answers · asked by L 2

How many liters of hydrogen gas are collected over water at 18 degrees celcius and 715mmHg when 1.14g of lithium reacts with water? Aqueous lithium hydroxide also forms

2007-03-21 10:31:00 · 1 answers · asked by bigtex24769 1

Which of the following is a strong acid?
a. 0.001 M HCl
b. 3.0 M HCl
c. both a and b
d. neither a and b
explain it to me pls. thanks

2007-03-21 10:30:22 · 2 answers · asked by chelsea_cruz20 1

Please help!!!
Thank you.

2007-03-21 10:24:23 · 1 answers · asked by perfection7 2

See if you can do 10 or more.

2007-03-21 10:22:41 · 2 answers · asked by Ryan M 1

How do you know whether the change in entropy favors the forward or reverse reaction. We are now learning about reaction energy.
For example,
HCL(l) <=> HCl (g) is this reverse reaction. im just taking a guess and if im right can you please tell me how to do this.

2007-03-21 10:12:29 · 1 answers · asked by Anonymous

A solution contains 2.0x10^-4 M Ag and 1.5x10^-3M Pb. If NaI is added, will AgI (Ksp = 8.3x10^-17) or PbI (Ksp= 7.9x10^-9) precipitate first? Specify the concentration of I needed to begin precipitation.

Please help me learn how to solve
this problem.

2007-03-21 09:50:07 · 4 answers · asked by __ 3

in chemistry class im doing different types of energy. i need a specific type for electrical, mechanical, nuclear, radiant and thermal, and state how can it be obtained, how can it be used and how can it be transferred.




i have already done one for chemical, i used gasoline, it can be obtained by pumping it out of the ground, it can be used to run cars, and it can be transferred by force and motion


thanks

2007-03-21 09:49:13 · 2 answers · asked by Miss 21 5

A college says I need to take a Introduction to Chem. class that is a lab with 4 credits, Is Prep for Chem the same thing? It also has 4 credits and it is a lab. I'm not sure...

2007-03-21 09:48:40 · 1 answers · asked by Lydia J 1

2007-03-21 09:40:40 · 4 answers · asked by Gene G 1

Does changing the number of neutrons in the nucleus of an atom change the chemical properties of the element? Explain.

2007-03-21 09:39:04 · 6 answers · asked by Thejames A 1

The following equilbrium partial pressures were measured at some temperature at some temperature
NH3-->0.310 atm
N2-->0.180 atm
H2-->0.150 atm

2NH3 <-> N2 + 3H2

In a different experiment at the same temperture, the equilibrium pressure of N2 was found to be 0.180atm and that of H2 to be 0.350 atm. What is the equilibrium pressure NH3 if K = 5.490 for the above reaction at the temperature of the equilibrium?
P(NH3) = ______atm

Please Help By Explaining!!

2007-03-21 09:28:53 · 1 answers · asked by beachbum 2

2007-03-21 09:27:44 · 4 answers · asked by Joyce 4

If gases can be compressed, can solids and liquids?? Also what does compressed mean?? Thank you!!

2007-03-21 08:34:22 · 13 answers · asked by DK :) 2

how many grams of phosphorus react with 35.5 liter of 02 at stop to form tetraphosphorus decaoxide? P4(s) + 502(g)--->P4010(s)

2007-03-21 08:32:31 · 1 answers · asked by unknown 1

a) [ Q ] = [ QH + ]


b) [ Q ] > [ QH + ]


c) [ QH + ] > [ Q ]



Using the letters for the above relationships identify the dominant quinine species for each of the following steps of the above titraion.



I. At the start of the titration



II. At the halfway-point



III. At the equivalence point

2007-03-21 08:18:12 · 2 answers · asked by Gemini 2