Chemistry - October 2007

1) Hydrogen cyanide is used in the manufacture of clear plastics such as Lucite and Plexiglas. It is prepared from ammonia and natural gas (CH4).

2NH3(g) + 3O2(g) + 2CH4(g) --> 2HCN(g) + 6H2O(g)

The reaction evolves 739 kJ of heat per 2 mol HCN formed. What is the value of q (in kJ)?

2) Hydrogen sulfide, H2S, is produced during decomposition of organic matter. When 0.5000 mol H2S burns to produce SO2(g) and H2O(l) -282.7 kJ of heat is released. What is this heat in kilocalories?

2007-10-18 07:40:26 · 1 answers · asked by keya_na 2

2007-10-18 07:36:05 · 5 answers · asked by Anonymous

2007-10-18 07:35:57 · 12 answers · asked by Anonymous

in terms of molecular structure of the acids

2007-10-18 07:32:37 · 2 answers · asked by Anonymous

Methanol, CH3OH, can be produced by the following reaction.

CO(g) + 2 H2(g) CH3OH(g)
Hydrogen at STP flows into a reactor at a rate of 19.0 L/min. Carbon monoxide at STP flows into the reactor at a rate of 25.0 L/min. If 5.55 g of methanol is produced per minute, what is the percent yield of the reaction?

%

2007-10-18 07:32:29 · 1 answers · asked by My point exactly 5

2007-10-18 07:30:47 · 2 answers · asked by damanjd1 2

A. Proteins

B. Carbohydrates

C. Lipids

D. Monosaccharide

2007-10-18 07:25:07 · 5 answers · asked by Anonymous

2007-10-18 07:21:32 · 5 answers · asked by browneyedqt565 1

Carbon tetrachloride can be formed by reacting chlorine with methane:

CH4 + 2 Cl2 à CCl4 + 2 H2

Given that the heat of formation of methane is –75 kJ/mol and the heat of formation of carbon tetrachloride is –135 kJ/mol, determine the heat of reaction.

Given the following equations and Ho values given below, determine the heat of reaction at 298 K for the reaction:
2 N2(g) + 5 O2(g) =2 N2O5(g)
2 H2(g) + O2(g) = 2 H2O(l) Ho/kJ = -571.6
N2O5(g) + H2O(l) = 2 HNO3(l) Ho/kJ = -73.7
N2(g) + 3 O2(g) + H2(g) 2 HNO3(l) Ho/kJ = -348.2
JUST FOR INFO Ho = delta h degrees

The specific heat capacity of aluminum is 0.900 J/oC g. How much energy (kJ) is needed to raise the temperature of a 8.50 x 102 g block of aluminum from 22.8oC to 94.6oC?

2007-10-18 07:21:11 · 1 answers · asked by Marlon P 1

Did mass appear to be conserved during this chemical reaction? Use complete sentences for your answer. Yes or No is not an acceptable answer.

2007-10-18 07:14:24 · 1 answers · asked by Anonymous

I know that when the copper(II)sulfate pentahydrate reacts with sodium hydroxide it yields copper hydroxide. Then copper oxide reacts with head to form copper oxide and H20.

2007-10-18 07:10:12 · 2 answers · asked by Anonymous

2 NO2(g) --->N2O4(g)
If 36.4 mL of NO2 gas is completely converted to N2O4 gas under the same conditions, what volume will the N2O4 occupy?

please help. i need to understand how to do this for my test. the answer would be nice so i can check my answers.

2007-10-18 07:09:41 · 5 answers · asked by My point exactly 5

2007-10-18 07:04:14 · 4 answers · asked by dz 1

I am doing some work and im stuck on this question on kp can some1 plz help as I have a test tommorrow so a worked solution would really help me

In the gas phase PCL5 under goes thermal dissociation

PCl5 ----> PCl3 +Cl2 (note. reaction is reversible)

At a certain temperature, and at a total pressure of 3atm, 60% of the PCl5 originally present has dissociated when equilibrium is attained. Calculate the partial pressures of the gases at equilibrium and work out the value of Kp

Thankyou

2007-10-18 07:02:50 · 1 answers · asked by Anonymous

Hands up, I haven't got a clue what its on about, let alone how to work it out.... so for the benefit of others like me, can someone please enlighten?

I've noticed quite a few such questions on site regarding calclulating hybridization....with little response, so I'm not the only one in the dark about molecular chemistry.... so can you please answer as detailed as possible for future searches....Thanks (on behalf of many)

2007-10-18 07:00:44 · 2 answers · asked by ~☆ Petit ♥ Chou ☆~ 7

http://i40.photobucket.com/albums/e215/xxs3xp1stolxx/chem%20206/Picture1.png

2007-10-18 06:54:48 · 1 answers · asked by Anonymous

Potassium dichromate, K2Cr2O7, is used in tanning leather, decorating porcelain and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K2Cr2O7.

a) 9.490 × 1025 Cr atoms
b) 2.248 × 1024 Cr atoms
c) 1.124 × 1024 Cr atoms
d) 3.227 × 1023 Cr atoms
e) 1.613 × 1023 Cr atoms

2007-10-18 06:53:25 · 1 answers · asked by Jennifer W 1

When an element's nucleus changes to that of a new element, it is called:

mutation.

radiation.

radioactive decay.

ionic radioactivity.

2007-10-18 06:46:42 · 6 answers · asked by Anonymous

Given:
- Each mole of Fe(CN)6 (4-) loses exactly one mole of electrons in a reaction
- Once you know # of moles of electrons released, you know number of moles of electrons used to reduce...
- n(electrons) = n(Fe(CN)6 (4-))
- Moles after titrations I found were .0005 m, .000196 m

Does anyone know how I can find number of moles of electrons released? I have no idea where to start or what to consider to find the moles of electrons.

Thank you so much for your help :)

2007-10-18 06:46:32 · 3 answers · asked by Miller4Bears6 2

My problem ask? A 10.0ml sample of aqueous HCL requires 24.32 mL of 0.134 M NaOH to reach the endpoint. What is the molar concentration of HCL? The equations for the reaction is

NaOH + HCL -----> NaCl + H2O

2007-10-18 06:35:42 · 4 answers · asked by browneyez4u2c 1

plz reply soon.
i m having a test on the day after tomorrow

2007-10-18 06:31:34 · 4 answers · asked by darling 1

2007-10-18 06:28:46 · 6 answers · asked by damanjd1 2

Oxalic acid, H2C2O4, reacts with the chromate ion in acidic solution as follows:
H2C2O4(aq) + CrO4-2(aq)------>CO2(g) + Cr+3(aq)
What is the molarity of the oxalic acid solution if 10.0mL of this solution consumes 50.0mL of 0.0350 M CrO4-2? Could you guys please show the work step by step? Thank you

2007-10-18 06:22:52 · 1 answers · asked by Sky N. 1

what fuels a candle?

2007-10-18 06:04:10 · 5 answers · asked by Anonymous

For example, in NO3- I don't understand why its charge is -1.

2007-10-18 04:25:58 · 3 answers · asked by Victor A 1

One mole of nitrogen gas confined within a cylinder by a piston is heated from 0°C to 883°C at 1.00 atm.

Calculate the work of expansion of the gas in joules (1 J = 9.87 10-3 atm·L). Assume all the energy is used to do work.

What would be the temperature change if the gas were heated with the same amount of energy in a container of fixed volume? (Assume the specific heat capacity of N2 is 1.00 J/g·K.)

2007-10-18 03:42:42 · 1 answers · asked by b.schreiber1 1

CaCO3 + 2HCL = CO2 + CaCl2 + H2O

I think it is is a redox reaction because the CO3 becomes a CO2 .... is this correct ?

2007-10-18 03:11:50 · 6 answers · asked by immortal 2

2007-10-18 02:40:57 · 5 answers · asked by Anonymous

If I need to prepare a sodium hydroxide solution from solid sodium hydroxide pellets that is approximately 0.2M, how many grams of sodium hydroxide and how many mL of water do I need?

2007-10-18 02:35:44 · 4 answers · asked by Anonymous

2007-10-18 02:24:44 · 2 answers · asked by Anonymous