Chemistry - February 2007

All metals contract when they solidify, except two. Which two?

2007-02-23 00:59:40 · 2 answers · asked by eljay6969 1

2007-02-23 00:43:53 · 10 answers · asked by kartik 2

2007-02-23 00:24:58 · 7 answers · asked by Abhi k 1

Zn (aq) + Cu(NO3)2 yields Zn(NO3)2 (aq) and Cu (s).

Why is the copper displaced by zinc black in color and not brown in color? The original copper powder is brown in color.

2007-02-23 00:11:50 · 1 answers · asked by oxired 1

2007-02-22 22:44:38 · 4 answers · asked by Amy Mangal 1

If not KCl, Potassium Nitrate: KNO3
A Chemistry investigatory report

2007-02-22 22:35:16 · 7 answers · asked by MissUkraine2005Lover 3

This is actually for our term paper. We were asked what is the chemical basis of our chosen product. I picked that particular topic. Could anyone out there tell me what does this gluten ingredient does that causes a negative effect on people? Thanks! :)

2007-02-22 21:53:15 · 3 answers · asked by MiG 1

a) Pure copper can be produced by heating copper(II) sulfide in the presence of diatomic oxygen from the air. Sulfur dioxide gas is also produced in this reactions.

b) Water is formed by the explosive reaction between hydrogen gas and oxygen gas.

c) When baking soda (sodium hydrogen carbonate) is heated, it decomposes, forming the products sodium carbonate, carbon dioxide, and water.

2007-02-22 21:36:25 · 7 answers · asked by m C 1

2007-02-22 21:24:27 · 4 answers · asked by dunno_lehs 1

2007-02-22 21:23:43 · 4 answers · asked by dunno_lehs 1

a. How many grams of alcohol are in a solution with 12% (v/v)?
b. How many grams of alchol are in a solution with 12% (w/v)?

Please I need it ASAP. Thanx!

2007-02-22 21:21:17 · 3 answers · asked by Lena 1

Is it possible to seperate the carbon from the oxygen in CO2???

2007-02-22 20:36:05 · 6 answers · asked by Adam B 1

what is the % purity of the sample?

2007-02-22 20:28:37 · 1 answers · asked by Anonymous

2007-02-22 20:00:41 · 4 answers · asked by Alric C 1

U want to make 500mL of an isotonic glucose solution to infuse into a patient.How many grams of glucose do u need?________g

2007-02-22 19:16:19 · 3 answers · asked by Anonymous

2007-02-22 19:03:34 · 3 answers · asked by sky_blue 1

How can the rate constant be determined from the graphs?
This is the slope of the graph? What about instantaneous rate of the reaction then?

2007-02-22 19:01:44 · 2 answers · asked by AmandaLiu 1

2007-02-22 17:03:03 · 1 answers · asked by Bryan 1

If only a few of the amino acid residues of an enzyme are involved in its catalytic activity, why does it need so many of them?

Thanks a bunch for all those who answer.

2007-02-22 16:59:55 · 1 answers · asked by surferbum24 1

Question 1
Two particles have the following composition:
i) 12 protons, 12 neutrons and 10 electrons and
ii) 11 protons, 12 neutrons and 10 electrons

They would be described as:
a) isotopes
b) positive ions (cations)
c) allotropes
d) negative ins (anions)
e) non-metal atoms

Question 2:
An atom with 8 electrons in its outer shell has a tendency:
a) to gain electrons
b) to lose electrons
c) neither gain nor lose electrons
d) to gain or to lose electrons
e) to gain protons

Question 3:
Consider each of the following materials. Classify them into three groups as elements, compounds or mixtures
a) sea water
b) soil
c) sulfur
d) steel
e) wine
f) titanium dioxide

Note: 1st and 2nd questions are multiple choice (one correct answer) Please tell me for the 3rd question which ones are compounds, which ones mentioned are elements and which ones are mixtures. Thankyou!

2007-02-22 16:52:55 · 2 answers · asked by Anonymous

2007-02-22 16:42:31 · 4 answers · asked by Anonymous

2007-02-22 16:14:46 · 4 answers · asked by saphira_samreena 1

a) CHCl=CHCl


b) CH2=CH-CHCl2


c) ClBrCHCl


d) (CH3)2C=CH-CH3


e) 1,1-dichloroethene

2007-02-22 15:11:55 · 5 answers · asked by JD 1

a) N--O

b) S--O

c) Na--Cl

d) Ca--O

e) Cl--F

2007-02-22 15:09:48 · 5 answers · asked by JD 1

Briefly comment on the effect of a catalyst on each of the following.
(a) activation energy
A catalyst does not change the activation energy.
A catalyst raises the activation energy by changing the rate.
A catalyst lowers the activation energy by changing the rate.
A catalyst lowers the activation energy by changing the reaction mechanism.
A catalyst raises the activation energy by changing the reaction mechanism.

(b) reaction mechanism
A catalyst always makes a reaction mechanim more complicated.
A catalyst always simplifies a reaction mechanim.
A catalyst changes the reaction mechanism.
A catalyst does not change the reaction mechanism.

(c) enthalpy of reaction
A catalyst does not change the enthalpy of of reaction.
A catalyst changes the enthalpy of reaction, either raising or lowering it.
A catalyst always lowers the enthalpy of reaction.
A catalyst always raises the enthalpy of reaction.

2007-02-22 14:55:45 · 4 answers · asked by chance w 1

Hi everyone, I REALLY need ur help. There's a question seems like I can't quite understand (I have some idea about it though): the digital thermometer is miscalibrated by 0.15C higher over its entire range, how will the reported moles of solute in solution be affected? I'm doing a lab determining molar mass of a solid. And in the experiment, I have to use the thermometer to record the temperature while observing and then plot the points on the graph to determine the freezing point. I'm looking for a serious answer! Please help me! Thank you

2007-02-22 14:48:48 · 1 answers · asked by i_demand_him 1

Hey put this up earlier and never got a response i really need someones help

2007-02-22 14:44:55 · 2 answers · asked by mitch v 1

) 1.22 M sugar (C12H22O11) solution (density of solution = 1.12 g/mL)
m
(b) 0.42 M NaOH solution (density of solution = 1.04 g/mL)
m
(c) 4.72 M NaHCO3 solution (density of solution = 1.19 g/mL)
m

2007-02-22 14:42:26 · 1 answers · asked by chance w 1

2007-02-22 14:38:12 · 8 answers · asked by Anonymous

When they react, ____ will become the cation (positive ion) and ____ will become the anion (negative ion). Fill in the blanks with Li or Cl.

How would you write the Lewis dot structure for a Lithium ION and a Chlorine ION???

Thanx

2007-02-22 14:36:45 · 5 answers · asked by precious_angel321 3