Chemistry - November 2007

just trying to see what it becomes when all platinum group metals are combined does it become a new alloy or what does it have a name is it of any use

2007-11-21 10:07:09 · 1 answers · asked by pryze 1

AgNO3 + Na2 CO3 -> Ag2 CO3 + 2 NaNO3

2 AgNO3 + Na2 CO3 -> Ag2 CO3 + 2 NaNO3

4 AgNO3 + Na2 CO3 -> 4Ag2 CO3 + 2 NaNO3


Choose the answer that shows a correctly balanced equation.

Ni(NO3) 2 + 2 NaOH -> Ni(OH) 2 + 4NaNO3

Ni(NO3) 2 + 2 NaOH -> Ni(OH) 2 + 2 NaNO3

Ni(NO3) 2 + NaOH -> Ni(OH) 2 + 2 NaNO3


Choose the answer that shows a correctly balanced equation.

2 Mg + O2 -> 2 MgO

2 Mg + 2O2 -> 2 MgO

3 Mg + O2 ->3 MgO

Choose the answer that shows a correctly balanced equation.

2Cu + 3 AgNO3 -> 2 Ag + 2Cu(NO3) 2

4Cu + 2 AgNO3 -> 4 Ag + Cu(NO3) 2

Cu + 2 AgNO3 -> 2 Ag + Cu(NO3) 2

2007-11-21 10:03:06 · 3 answers · asked by xlhollisterboi 1

... in the electrolysis of AgNO3 (aq)?
a. 0.807
b. 48.5
c. 0.442
d. 3.23
e. 1.61

THank you

2007-11-21 09:59:49 · 1 answers · asked by Ciso101 2

MnO2 + NH4 --------> Mn2O3 + NH3 + H2O.

2007-11-21 09:53:44 · 2 answers · asked by xlhollisterboi 1

Is it becuase uranium mining is cheap? why would uranium mining be cheap?

2007-11-21 09:47:46 · 6 answers · asked by joy 3

2007-11-21 09:43:17 · 1 answers · asked by Anonymous

2007-11-21 09:37:34 · 6 answers · asked by Heyy!!! 1

Consider the following chart:
Compound Mass Iodine(g) Mass Fluorine(g)
(1) 4.75 3.56
(2) 7.64 3.43
(3) 9.41 9.86
When asked to find the mass of fluorine per gram of iodine in each compound, I found (1) 0.7495g F/g I , (2) 0.44895g F/ g I
(3) 1.0478g F / g I.

I am now asked to explain how these numbers support the atomic theory however, I don't see anyway how they do: they do not support the law of multiple proportions or any other part of the theory - AM I MISTAKEN? if so, how does this support the theory??

2007-11-21 09:20:45 · 3 answers · asked by confusedchemist 1

I did an experiment where I produced copper by combining Fe with CuCl2.2H2O.

I decanted the FeCl and H2O also produced and washed the copper 10 times with water and once with HCl. Then I left it to dry over the weekend.

The percentage yield was 73%.

How would I get an improved percentage yield if I performed this reaction again?

2007-11-21 09:20:36 · 1 answers · asked by ChemHelp 2

out of the following elements: Na , Fe, Sr, Mn, K, Cu, Cr, Ti

2007-11-21 09:20:24 · 2 answers · asked by bundu 1

1 mole of which substance, when added to 1L water, would give the highest concentration of silver(I) ions:
A) silver(I) chloride
B) silver(I) phosphate
C) silver(I) sulfate
D) silver(I) perchlorate
E) silver(I) sulfide

Thought it was B

2007-11-21 09:11:03 · 2 answers · asked by hpanna47 2

why would cause this reaction on your skin?

2007-11-21 08:54:09 · 3 answers · asked by sweetgirl78228 2

vineger is a solution of ethanoic acid. a 10cm^3 portion of a certain vinerger needs 55cm^3 of 0.2mol/dm^3.... wot is the consentration o f enthnoic acid in vineger?

2007-11-21 08:42:38 · 1 answers · asked by Anonymous

The internal energy change is 4:11 kJ when
an ideal gas expands from 3.50 to 28 liters
at a constant external pressure of 2:95 atm.
What is the heat absorbed by the gas from its
surroundings? Answer in units of kJ.

2007-11-21 08:12:47 · 1 answers · asked by rachlopez88 1

Can Someone please show me how to do this problem??? THANKS!!!!

2007-11-21 07:33:36 · 1 answers · asked by Anonymous

60 g of ice and 70 g of water are at equilibrium in an insulated container. 42 kJ of heat are delivered to this mixture via an electric heater. What is the final temperature of water in the container? Answer in C.

2007-11-21 07:18:34 · 2 answers · asked by beehappinow 1

please help, i understand that as pH increses the [H+] decreases, can anyone giv eme detailed answer to mek me undertand?????

2007-11-21 07:11:06 · 4 answers · asked by Anonymous

Consider the thremochemical equation :
2 A-A + B-B ~~> 2 A-B-A DH0 = - 200.0 kJ./mol
If the A-A and A-B bond energies are respectively 250.0 and 225..0
kJ/mol. calculate the B-B bond energy.

How is the answer 200KJ? Can't seem to figure it out

2007-11-21 06:55:48 · 2 answers · asked by hpanna47 2

What is the limiting reactant when 19.9 g of CuO react with 2.02 g of H2 according to the following: CuO+H2 ---->Cu+H2O

2007-11-21 06:43:11 · 2 answers · asked by Caramel 2

its for a science project. Answers would be greatly appriciated.

2007-11-21 06:28:40 · 2 answers · asked by kYLE-CON! 2

how do i know if something is Acids/Bases/Neutral if i was giving the forumla?

2007-11-21 06:19:15 · 1 answers · asked by Ayaa 1

(a) An ideal gas occupies a volume of 1.0 cm^3 at 20ºC and atmospheric pressure. Determine the number of molecules of gas in the container.

(b) If the pressure of the 1.0-cm^3 volume is reduced to 1.0 X 10-11 Pa (an extremely good vacuum) while the temperature remains constant, how many moles of gas remain in the container?

2007-11-21 06:15:34 · 7 answers · asked by Anonymous

The my last question is
"For each of the following naturally occurring oils: Citronella, eucalyptus, cinnamon leaf, nutmeg, clove, rose, jasmine, lavender; -
c) Are there any harmful effects using the chemically produced ones?"

The answer for this question can be view in this website;

http://au.answers.yahoo.com/question/;_ylc=X3oDMTE1MmI4N2IyBF9TAzIxMTU1MDAxMTgEc2VjA2Fuc19ub3QEc2xrA3N1YmplY3Q-;_ylv=3?qid=20071016125901AA6dCdg

My next question is;
- Do you mean to say that synthetic essential oils would have be safer in the sense that they do not contain ketones? As i understand it, ketones are toxic & occurs in natural essentials oils only.
- Why is sage high in ketones but not toxic?

2007-11-21 06:12:57 · 2 answers · asked by md_novilz 1

alkanes have a high melting point (i worked out that much) but how does this influence their use as fuels?

2007-11-21 06:11:49 · 6 answers · asked by Anonymous

For the gaseous reaction of carbon monoxide and chlorine to form phosgene, (COCl2), calculate each of the following.

(a) Calculate S° at 298 K (H° = -220. kJ/mol and G° = -206 kJ/mol).
_____ J/K·mol
(b) Assuming that S° and H° change little with temperature, calculate G° at 301 K.
_____ kJ/mol

2007-11-21 06:01:26 · 4 answers · asked by Kimberly L 1

Calculate G° for each reaction using G°f.

(a) MnO2(s) + 2 CO(g) ~> Mn(s) + 2 CO2(g)
______ kJ
(b) H2(g) + I2(s) 2 HI(g)
_____kJ
(c) NH4Cl(s) ~> NH3(g) + HCl(g)
_____ kJ

2007-11-21 05:59:47 · 1 answers · asked by Kimberly L 1

2007-11-21 05:57:25 · 3 answers · asked by cmsb705 5

Without using absolute entropy values, predict the sign of (the change in S degrees) for each of the following processes.
(a) NaClO3(s) ~> Na+(aq) + ClO3-(aq)
-positive
-negative
(b) NH3(g) + HBr(g) ~> NH4Br(s)
-positive
-negative
(c) H2S(g) + 1/2 O2(g) ~> 1/8 S8(s) + H2O(g)
-positive
-negative

2007-11-21 05:53:14 · 2 answers · asked by Kimberly L 1

If any one can help, I would be grateful. I would be interested in how this is calculated or where I can find the data.

2007-11-21 05:46:54 · 3 answers · asked by david s 2

What is the total motional contribution to the molar internal energy of gaseous BF3?

1. 3RT
2. RT
3. 1.5RT
4. 3.5 RT
5. 2.5RT

For reaction in which gases are neither produced nor consumed, change in heat is...
1. less than change in energy
2. the same as change in energy
3. unrelated to change in energy
4. greater than change in energy

2007-11-21 05:42:10 · 1 answers · asked by beehappinow 1