Chemistry - November 2007

What mass of KNO3 would have to be decomposed to produe 21.1L of Oxygen measured at STP?

2007-11-30 05:18:44 · 3 answers · asked by youssef a 1

O3, O2, CO, CO2, or H2O

2007-11-30 05:12:24 · 3 answers · asked by JoJo 2

The vapor pressure of dichloromethane, CH_2Cl_2, at 0 degrees C is 134 mmHg. The normal boiling point of dichloromethane is 40 degrees C.

2007-11-30 05:07:05 · 3 answers · asked by Anonymous

What molecule is the worst greenhouse gas considering its total impact on the atmoshphere? Please help!!!

2007-11-30 05:00:40 · 7 answers · asked by deebee 2

The specific heat of copper metal is 0.385 J/g·K. How many joules of heat are necessary to raise the temperature of a 1.41 kg block of copper from 27.2°C to 85.2°C?

2007-11-30 04:58:22 · 2 answers · asked by JTOWN 2

i am a mechanic and i have heard that burning antifreeze (ethylene glycol) produces mustard gas or something like it. this concerns me cause there are instances where i might be exposed to burning antifreeze such as spilling some on a hot engine.

2007-11-30 03:20:56 · 3 answers · asked by pimpjon 3

2007-11-30 03:06:05 · 4 answers · asked by Anonymous

The part that I am having a problem with is the reaction between I2 and KI. I know KI is a reactant and I2 is a product, and that there must be electrons somewhere in the reaction, but I can't figure out how all that fits in.

2007-11-30 03:01:53 · 1 answers · asked by Eliza L 1

Substance A has a vapor pressure(mmHg) of 275
Substance B has a vapor pressure (mmHg) of 459

Which has a higher heat of vaporization

Has a higher boiling point

is a gas at 300 mmHg

has weaker intermolecular forces

2007-11-30 02:57:56 · 2 answers · asked by Anonymous

if 28.2 g C20 H42 is dissolved in 500 g of C6H6(pure P 25 degrees = 93.4 torr), then what is the vapor pressure (in Torr) of the solution at 25.0 degrees celcius.

2007-11-30 02:56:55 · 2 answers · asked by confusedkid 3

What are the steps in getting the answer to these kinds of question? How about if I only had the Molarity and the Ka of the acid?

What is the pH of a solution in which 20.0 mL of 0.10 M NaOH are added to 25.0 mL of 0.10 M HCl?
1) The answer is: 1.95.

2007-11-30 02:42:30 · 3 answers · asked by Summer Productivity 1

I know noble gases are the most inclined to follow the octet rule, but I'm fairly certain Xe doesnt -- because there is an extended octet. Is an extended octet a direct violation of the octet rule, and does Xe violate it in this way despite its nobility? Thank you so much in advance.

2007-11-30 02:32:40 · 3 answers · asked by Anonymous

Select all of the following that appropriately define a chemical bond in VALENCE bond theory.

1.A chemical bond results from the overlap of a completely filled atomic orbital with an empty orbital.

2.A chemical bond is the sharing of electrons represented as dots.

3.The electrons involved in bonding are located in orbitals localized on individual atoms.

4.A chemical bond results from the overlap of two half-filled orbitals with spin-paring of the two valence electrons.

5. A chemical bond results from electrons occupying a nonbonding molecular orbital.

6.A chemical bond results from electrons occupying a bonding molecular orbital.

2007-11-30 02:13:11 · 1 answers · asked by Donna L 3

Which one of the following statements is ALWAYS true according to VSEPR theory?

1.The shape of a molecule is determined by repulsions among nonbonding electron groups.

2.The shape of a molecule is determined by the polarity of its bonds.

3.All of these are true.

4.The shape of a molecule is determined by repulsions among all electron groups on the central atom.

5.The shape of a molecule is determined by repulsions among bonding electron groups.

2007-11-30 02:12:00 · 3 answers · asked by Donna L 3

If you heat 1200 grams of water from 22.3'C to 78.9'C, how many joules of heat did it absorb?

2007-11-30 01:50:18 · 4 answers · asked by Anonymous

Enthalpy Change?
NaClO + Na2S2O3 . 5H20
Create ionic equation
Calculate the enthalpy change of react

2007-11-30 01:33:24 · 0 answers · asked by Puka 1

How does the idea of photons of light explain the photoelectric effect?

2007-11-30 01:24:35 · 2 answers · asked by dk 6

2007-11-29 20:16:13 · 4 answers · asked by Miss Zippy 2

Calculate [CO32-] in a 0.026 M solution of CO2 in water (H2CO3). If all the CO32- in this solution comes from the reaction shown below, what percentage of the H+ ions in the solution is a result of the dissociation of HCO3-?

HCO3-(aq)<---->H+(aq) + CO32-(aq)

2007-11-29 19:07:03 · 1 answers · asked by Kim N 2

It's just really annoying.

I wish most people in this section actually cared about the subject.

2007-11-29 18:04:16 · 7 answers · asked by Anonymous

is it synthesis of atp? structural components of cells/tissues? transport of cholesterol? or enzymes?

--please help. im stuck. i thought it was one of the first 2 but i need to be definate. only answer if you are certain!!!!

2007-11-29 17:59:46 · 1 answers · asked by Anonymous

Calculate [OH -], pOH, and pH for each of the following.
(a) 0.00035 M Ca(OH)2
[OH -]
M
pOH

pH

(b) a solution containing 19 g of KOH per liter
[OH -]
M
pOH

pH

(c) a solution containing 190.0 g of NaOH per liter
[OH -]
M
pOH

pH

2007-11-29 16:05:54 · 1 answers · asked by e36m3_98 1

Is it Na3 (BO3)

2007-11-29 15:32:10 · 0 answers · asked by bomerman65 1

An atom of sodium has a larger mass than an atom of neon. How is this possible when neon has so many more valence electrons?

2007-11-29 15:29:16 · 8 answers · asked by Anonymous

Describe the general trends in acid base character of the oxides of the elements in the third period (Na to Ar). Give examples of one acidic oxide and one basic oxide and show wiuth equations how these oxides react with water.

2007-11-29 15:03:39 · 2 answers · asked by moviefan254 1

An unknown gas, X2(g), which behaves much like N2(g) (NN), is analysed and the following enthalpies of formation are obtained:
Gas
X(g) 376 kJ/mol
H(g) 217 kJ/mol
X2H4(g) 442 kJ/mol


We also know that the X-H bond energy is 267 kJ/mol.
Use this information to estimate the X-X (single-)bond energy in the X2H4 molecule

Please do explain the proper method and the various steps used to solve this problem.
Thank you.

2007-11-29 14:54:58 · 1 answers · asked by Anonymous

please solve these single replacement reactions! PLZ TRY INCLUDING STEPS

1. zinc metal is placed in a solution of copper (II) sulfate
2. a small piece of sodium metal is added to distilled water
3. Chlorine gas is bubbled into a solution of sodium iodide

FIRST ONE TO ANSWER N SHOW STEPS CORRECTLY GETS 10 PTS!

2007-11-29 14:49:31 · 4 answers · asked by !!!!!! 3

1.Draw Lewis structures for iodine monochloride, ICI, and hydrogen bromide, HBr
2.Using iodomethane, CH3I, as a model, draw the lewis strutuctre for dichlormethane, CH2Cl2
3.Draw the Lewis structure for methanol, CH3OH. Draw the CH3 part first, then add O and H.
4.Draw the Lewis structure for ethane, C2H6
********* plz help these were the only probelms i didnt get! plz help me! u can put answer here or email me at Basra1@sbcglobal.net
**** plz help show u got a heart i need to pass this class plzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

2007-11-29 14:39:25 · 1 answers · asked by manny 1

2007-11-29 14:32:45 · 1 answers · asked by Gio Lapid 2

What mass of SO3 is produced from the reaction b/t 31.5g S8 and 8.65g of O2?

What mass of H2SO4 is produced from the reaction of 6.58g of SO3 and 1.64g of H2O?

If 21.4g of aluminum is reacted w/ 91.3g of Fe2O3, the products will be Al2O3 and iron. What mass of iron will be produced?

can you please explain these in detail so I understand. =]

2007-11-29 14:18:43 · 2 answers · asked by shelbers_rawrrr 2