Chemistry - November 2007

2007-11-02 14:08:19 · 2 answers · asked by tessababy992006 1

2007-11-02 14:07:00 · 2 answers · asked by tessababy992006 1

2007-11-02 14:06:24 · 2 answers · asked by tessababy992006 1

2Al+3CuO-----> Al2O3+3Cu2
2H2O--->2H2+O2
AB+CD--->AC+BD
Propane burns in oxygen to produce cardon dioxide and steam.

2007-11-02 14:03:34 · 1 answers · asked by Anonymous

i thought it was enzymes but i am told it is an organism (cellulose based biopolymer)

2007-11-02 13:52:14 · 2 answers · asked by jin_ale 2

Studies have proven conclusively that flouride is an effective tooth decay preventative. As a result, in the late 1960's and 1970s, many communities in the United States began adding trace quantities of flouride to their drinking water supplies. However, strong opposition arose against this "tempering' with the water supply. One of the common arguments was that flourine was known to be a deadly gas. What would be your response to this argument?

2007-11-02 13:44:31 · 2 answers · asked by Anonymous

How many moles of H+ ions are present in 1.25L of .075M HNO3?

2007-11-02 11:30:51 · 3 answers · asked by burgler09 5

Two questions:
1. calculate the expected change in temperature for 4.5 g of NH4NO3 dissolved in 100.0 mL of H20. Assume that the calorimeter absorbs no heat. (ie. Ccal=0)

2. Calculate the change in temperature for 4.50 g of CaCl2 dissolved in 90.0 mL of H20. Assume that the calorimeter absorbs no heat (ie. Ccal=0)

2007-11-02 11:20:11 · 1 answers · asked by Anonymous

5.00 mL of 0.250 M HClO4 diluted to 30.0 mL

2007-11-02 11:19:10 · 3 answers · asked by JTOWN 2

2H2 + 2 O2 ---> 2 H2O
Zn(s) + H2SO4(aq) ----> ZnSO4(aq) + H2(g)
H2O(l)+ NH3 ---> NH4 + OH
Cl2 + 2KBr ---->Br2 + 2 KCl

2007-11-02 11:15:21 · 2 answers · asked by burgler09 5

Glycerol, C3H8O3, is a substance used extensively in the manufacture of cosmetics, foodstuffs, antifreeze, and plastics. Glycerol is a water-soluble liquid with a density of 1.2656 g/mL at 15°C. Calculate the molarity of a solution of glycerol made by dissolving 80.000 mL glycerol at 15°C in enough water to make 300.00 mL of solution.

2007-11-02 11:10:29 · 2 answers · asked by JTOWN 2

ive done the enzyme essay expt both purified and crude ones.
i need to get specific activity and i have done it
bt i am not so sure about it so plz check my answers
and if its wrong plz correct me!!

Activity of the purified enzyme
ΔAbs /min of 0.538
[got if from the spec with 400nm]
From Beer-Lambert Law A= εcl;
0.538=18300c ∴ c= 0.0000294 mol/l =0.0294mmol/l =0.0294umol/ml
The cuvette volume was 4mls
∴ 0.1ml AP transformed 0.1176umol pNPP per min
∴ 1ml AP 1.176 umol pNPP per min.
∴ the activity of the enzyme is 1.176 IU/ml enzyme.
Activity of the crude enzyme
ΔAbs /min of 0.320
A= εcl → 0.320=18300c ∴c=0.0000175 mol/l = 0.0175mmol/l=0.0175umol/ml
The cuvette volume was 4mls
∴ 0.1ml of crude enzyme transformed 0.07umol pNNP per min
∴ 1ml of crude enzyme 0.7umol pNPP per min
∴ the activity of the enzyme is 0.7 IU/ml enzyme



protein conc for crude is 13.6mg/ml
protein conc for purified is 0.05mg/ml

i dnt know if i need to use those protein conc figures!!

2007-11-02 10:40:08 · 3 answers · asked by Anonymous

Or, how were the earliest elements discovered, and how were they known to be elements?

2007-11-02 10:27:49 · 3 answers · asked by Anonymous

the formula XCI

2007-11-02 10:21:52 · 3 answers · asked by Anonymous

a) The triple point of CO2 is -57oC and 5 atm
b) CO2 boils at 73 atm and about -50oC
c) The melting temperature of a substance is more dependent on pressure than is its boiling boint
d) At 5 mm Hg and 100oC H2o=O is only in the gas phase

2007-11-02 09:49:24 · 1 answers · asked by T-BuKeTz 2

a) Volatiltiy of a liquid decreases with increasing temperature

b) The equilibrium vapor pressure of a liquid results from equal rates of evaporation and condensation

c) The equilibrium vapor pressure of a liquid remains constant as temperature changes

d) The vapor pressure of a liquid at its normal boiling point is strongly affected by the type of molecules the liquid consists of

2007-11-02 09:48:27 · 1 answers · asked by T-BuKeTz 2

2007-11-02 09:38:14 · 2 answers · asked by Anonymous

What is the difference between an acid and a salt? I know that aqueous hydrogen is an acid and aqueous salt has many X+ or X++ in solution. Is acid not a salt because it is made of the same elements as the solution (H+ and OH-)? Gah! This never was my better point in chemistry.

2007-11-02 09:26:24 · 3 answers · asked by Anonymous

2007-11-02 09:21:20 · 3 answers · asked by Anonymous

2007-11-02 09:20:04 · 2 answers · asked by Anonymous

how can i show what happens to the electrons when NaF is formed by ionic bonding

2007-11-02 08:55:30 · 6 answers · asked by Anonymous

Phosphoric acid is produced through the reaction between tetraphosphorous decoxide (P4O10) and water.

2007-11-02 08:50:30 · 5 answers · asked by Caramel 2

What volume (to the nearest 0.1 mL) of 4.30-M HCl must be added to 0.350 L of 0.200-M K2HPO4 to prepare a pH = 7.80 buffer?

I keep getting 13mL by making a rxn table and finding x. Then converting from L-Ml I am doing something wrong.

PH=Pka+log(b/a)
H3O+HPO4<->H30+H2PO4
x........(.07)........n/a........0
-x........-x............n/a........+x
0........(.07-x).....----........x

I found x to be .0557mols

.0557mols=4.30M * (#L)
(#L)=.01295L *1000mL=12.95mL

What am I doing wrong?

2007-11-02 08:32:25 · 1 answers · asked by Anonymous

Rank the following 0.10 M solutions in order of increasing pH (lowest pH to highest pH):

HOCl HNO3 HF NaCl

Rank the following 0.10 M solutions in order of increasing pH:

HC2H3O2 NaCl NH3 HCl KOH

2007-11-02 08:11:57 · 3 answers · asked by Guinness 3

I know it is 90% Au and 10% Cu - roughly
But I need the chemical formula.

2007-11-02 07:48:36 · 4 answers · asked by Cryst17 2

2007-11-02 07:21:34 · 1 answers · asked by Anonymous

2007-11-02 07:18:34 · 1 answers · asked by Anonymous

Which of the following four statments are true for real gases and the corrections that must be made to the Ideal Gas Law?
a) the constant a in van der waals equation corrects for attractions between particles
b) particles attract and repel each other
c) the volume of particles reduces observed pressure
d) the constant b in van der waals equation corrects for volume of real particles

2007-11-02 07:04:40 · 1 answers · asked by chemstinks926 1

Sodium Hydroxide

Ammonia

Sodium Bicarbonate

Salt

And what would be a good base to use in chemistry.

2007-11-02 06:57:39 · 2 answers · asked by John R 4

2007-11-02 06:07:20 · 5 answers · asked by Rupinder G 1