Chemistry - October 2007

What are some chemical changes that occur in nature that some people believe are harmful to the environment?

2007-10-10 11:46:03 · 2 answers · asked by -peanut- 3

A mixture contained zinc sulfide, ZnS, and lead sulfide, PbS. A sample of the mixture weighing 6.17 g was reacted with an excess of hydrochloric acid. The reactions are


ZnS(s) + 2HCl(aq) ==> ZnCl2(aq) + H2S(g)

PbS(s) + 2HCl(aq) ==> PbCl2(aq) + H2S(g)


If the sample reacted completely and produced 1.051 L of hydrogen sulfide, H2S, at 23oC and 745 mmHg, what were the percentages of ZnS and PbS in the mixture.

2007-10-10 11:44:04 · 1 answers · asked by Joe C. 1

a mole of sodium has a mass of 23.0g
how many atoms are present in a 156g sample

so i said 156/23=6.78
6.78(6.02*10exp23)=4 081 560 atoms

2007-10-10 11:31:33 · 4 answers · asked by Josh j 1

For the reaction show below determine the rate law.

H2O2 + 3I-(aq) + 2H+(aq) → I3-(aq) + 2H2O (l)


The following data were obtained:

[H2O2] [I-] [H+] Initial Rate (mol/L s)
0.10 0.10 0.10 1.15 x 10-4
0.10 0.20 0.10 2.30 x 10-4
0.20 0.20 0.10 4.60 x 10-4
0.20 0.10 0.20 2.30 x 10-4


Calculate the rate law for this reaction


They want the answer in rate = k [H2O2] [I-] [H+]

2007-10-10 11:23:42 · 1 answers · asked by duldey D 2

a) OF2

b) N3-

c) NH3O

d) BrF3

e) C2H6O

2007-10-10 11:23:16 · 1 answers · asked by Anonymous

2007-10-10 11:23:02 · 1 answers · asked by arima87 1

Which of the following compounds do not require resonance structures to provide a reasonable description ?

a) ClCCH

b) CO32-

c) NH3O

d) BrF3

e) H2O2

2007-10-10 10:51:07 · 1 answers · asked by gotMUNCH 2

2007-10-10 10:32:02 · 2 answers · asked by Kierra R 1

2007-10-10 10:27:58 · 2 answers · asked by Anonymous

i have a chemistry question and cant find the answer in the book. It asks
"How many electrons can occupy an orbital?"

i know that for n=1 you get 1
and for n=2 you get 4
and n=3 you get 9

but how high does it go an dhow man can occupy the orbital?

Thanks for your help!

2007-10-10 09:58:52 · 5 answers · asked by john s 3

i combined acetic acid and sodium (l) bicarbonate and captured the gas. How would i find the volume of the gas?

2007-10-10 09:40:44 · 2 answers · asked by Anonymous

how does it function?its putrpose?effect?harm?what is it?

2007-10-10 08:48:23 · 3 answers · asked by Spicy***princess 1

2007-10-10 08:41:53 · 2 answers · asked by hikdsjutrj 1

2007-10-10 08:31:50 · 7 answers · asked by Pastinie 3

SO2 + O2 -----> ?

2007-10-10 07:51:16 · 1 answers · asked by Chuck 1

16
S
32.06

A. 4.5
B. 9
C. 18
D. 36

2007-10-10 07:26:23 · 8 answers · asked by chris 1

What Happens If Metals React With Oxygen?

2007-10-10 07:17:16 · 10 answers · asked by Anonymous

Oxygen,Zinc,and Iodine, Which One is likely to be a poor conductor of electricity and a brittle solid at room temperature ???

2007-10-10 07:16:31 · 5 answers · asked by Ben M 1

his is the method I used:

2.0312 g of chalk / suspended in 100cm3 of water and 50cm3 of HCl(excess). Mixture is boiled for 1 minute then cooled and then its titrated against NaOH.

the Molarity of the HCL is 0.9931
the Molarity of the NaOH is 0.9931

the result of the titration is 9.9 (NaOH in the buirette and the excess HCl in the flask)

My calculation:

HCl(excess) + NaOH ---> xxxxxxx

moles of NaOH = (0.9931x10.00)/1000 = 9.931x10^-3 moles
1:1 ration with HCl so moles of HCl = 9.931x10^-3 moles

Moles of the HCl used at the start of the experiment = (0.9931x50.00)/1000 = 0.49655 moles

Amount of HCl used in the equation below = 0.49655 - (9.931x10^-3) = 0.039724 moles

CaCO3 + 2HCl ------> xxxxxxxx + excess HCl


its a 1:2 ration so 0.039724 / 2 = 0.019862 moles of CaCO3
Mr of CaCO3 = 100.087
Mass of CaCO3 = 100.087 x 0.019862 =1.988g
therefore Percentage w/w is 97.87%

does it look right?

2007-10-10 06:58:27 · 4 answers · asked by 421 4 1

A. ADP.
B. RNA.
C. AMP.
D. ATP.

2.)Life's system for coordinating and controlling the interlocking processes that allow cells to work harmoniously together is called

A. replication.
B. looping.
C. feedback
D. community

2007-10-10 06:16:10 · 2 answers · asked by LaKeshia H 1

If I just use tap water to rinse out this cup until I don't see anything, do the added chemicals in tap water kill the bacteria?

2007-10-10 06:04:54 · 2 answers · asked by Anonymous

2007-10-10 05:07:45 · 2 answers · asked by Indah S 2

this question is preferred to be answered by chemistry, biology majors or professors.

2007-10-10 05:00:29 · 2 answers · asked by R C 2

2007-10-10 03:05:34 · 1 answers · asked by zerald 1

1. Si4H10 + O2 = SiO2 + 10H2O

2. NH3 + O2 = N2H4 + H2O

3. C12H26 + O2 = CO2 + H2O

Thanks in advance

2007-10-10 01:36:04 · 2 answers · asked by Anonymous

this is for work in school, ffs answer you dildos

2007-10-10 01:13:48 · 11 answers · asked by bob d 1

show work and steps

2007-10-10 00:52:25 · 2 answers · asked by rrai 3

can we use absolute ethanol replace the use of 50% ethanol by jz diluting it to 50% ? will the result same as we use 50% ethanol? how much of WATER should be added to absolute ethanol to make 50% of 500ml ethanol?

2007-10-09 22:11:31 · 3 answers · asked by Anonymous

Each liter of an electrolyte solution contains 3.5 g sodium chloride, 1.5 g potassium chloride, 2.9 g sodium citrate (Na3 C6 H5 O7) and 20.0 g glucose (C6 H12 O6).

Calculate the molarity of each species present in the solution.

PLZ HELP.....I dont understand this!

2007-10-09 19:33:27 · 1 answers · asked by sweaty teddy 4

I need an answer right away so please answer in full detail because i really don't understand this.

What is the molar mass of an ideal gas if a 0.622 g sample of this gas occupiies a volume of 300 mL at 35C and 789 mm Hg?

Ok, so i know i have to make the Celsius to Kelvin, but am i plugging this inter the PV=nRT equation? and what am i looking for?

2007-10-09 19:31:03 · 1 answers · asked by Shookoolate 3