Chemistry - April 2007

2007-04-23 12:33:05 · 2 answers · asked by Anonymous

if DNA is ATG
what will mRNA, and tRNA be?
i don't understand this?

2007-04-23 12:13:15 · 2 answers · asked by JJcD 4

sample now weighs extremely less: 1.208g. with the white residue you hav left you decide to perform a molar mass experimentation giving u 105.99g/mol.
a.) using the original mass and the molar mass of ur anhydrous salt, determine the moles of salt you are working with?
b.)using the mass of water lost and the molar mass of water determine the moles of water you are working with?
c.)divide b by c. this whole number of moles of water in your molecular formula.
d.)if your anhydrous salt is sodium carbonate write the formula for this hydrate.

when i tries this i got it wrong!
this is what i got!
a.) 218.1 mol of salt
b.) 90.09 mol water
c.) 2.421
d.) Na2CO3

2007-04-23 12:05:14 · 1 answers · asked by Gabe 1

where can i get the materials and yes it is the ingredient to gun powder

2007-04-23 11:59:11 · 5 answers · asked by edward l 1

For the reaction N2O4(g) <--->2NO2(g) , Kp = 0.25 at a certain temperature. If NO2(g) is placed in an otherwise empty container at an initial pressure of 0.050 atm, calculate the equilibrium pressures of NO2(g) and N2O4(g).


If the amount of NO2 that reacts to reach equilibrium is 2x, then the pressures at equilibrium (in terms of x) are

PN2O4 = x
PNO2 = 0.050-2x

Substitute the equilibrium pressures of NO2 and N2O4 (in terms of x) into the equilibrium expression and solve for x.

2007-04-23 11:50:43 · 1 answers · asked by lila 1

a) For binary acids HA in the same row of the periodic table, the greater the electronegativity of A
the weaker the acid HA

b) For binary acids HA in the same column of the periodic table, the weaker the H-A bond
the stronger the acid HA

c) HBr is a stronger acid than HCl

d) H2SO3 is a weaker acid than H2SO4

e) HBrO is a stronger acid than HIO

f) For carboxylic acids : the greater the electronegativities of the atoms in the group bonded to the carboxyl group,
the stronger the acid

2007-04-23 11:04:14 · 1 answers · asked by Anonymous

a) CH3COOH(aq) + NH3(aq) = CH3COO-(aq) + NH4 +(aq)

b) Cu 2+(aq) + 4NH3(aq) = Cu(NH3)42+(aq)

c) CCl3COOH(aq) + H2O(l) = CCl3CO2-(aq) + H3O+(aq)

d) BF3(g) + (CH3CH2)2O(l) --> (CH3CH2)2OBF3(l)

2007-04-23 10:46:07 · 3 answers · asked by American Girl 1

I know a is wrong but i dont know about the rest


a) NH3 : A Bronsted base, but not a Lewis base

b) OH - : A Bronsted base and a Lewis base

c) CH3COOH : A Lewis acid, but not a Bronsted acid

d) Ni 2+(aq) : A Bronsted acid, but not a Lewis acid

e) CH3CH2CH2CH3 : Both a Bronsted acid and a Lewis acid

2007-04-23 10:37:54 · 1 answers · asked by American Girl 1

I know a and c are right but i dont knnow about the rest!


a) For binary acids HA in the same row of the periodic table, the greater the electronegativity of A
the weaker the acid HA

b) For binary acids HA in the same column of the periodic table, the weaker the H-A bond
the stronger the acid HA

c) HBr is a stronger acid than HCl

d) H2SO3 is a weaker acid than H2SO4

e) HBrO is a stronger acid than HIO

f) For carboxylic acids : the greater the electronegativities of the atoms in the group bonded to the carboxyl group,
the stronger the acid

2007-04-23 10:34:11 · 1 answers · asked by American Girl 1

What type of intermolecular forces are active in the liquid state of each of the following substances?

a) HI
b) N2 (subscript 2)
c) Ar
d) P4 (subscript 4)

2007-04-23 10:32:04 · 1 answers · asked by MGK 1

a) HIO4 and IO4-
b) HClO4 and Cl -
c) KOH and OH -
d) HBr and Br -
e) H3O+ and H2O

2007-04-23 10:20:19 · 2 answers · asked by American Girl 1

that the % acetic acid in vinegar may vary? (please explain your answer)

2007-04-23 09:42:57 · 3 answers · asked by Anonymous

The equation is: CH4(g) + CO2(g) <--> 2CO(g) + 2H2(g)
(the <--> stands for at equilibrium)

A 1.00-L flask is filled with 0.30 mol of CH4 and 0.40 mol of CO2, and allowed to come to equilibrium. At equilibrium, there are 0.20 mol of CO in the flask. What is the value of Kc, the equilibrium constant, for the reaction?

A. 1.2
B. 0.027
C. 0.30
D. 0.060
E. 3.0

2007-04-23 09:18:25 · 3 answers · asked by delilah 2

CAn someone please help me

You blow up a football with an airpump until the football becomes hard. if the football is not used for a period of time, it became soft. Describe what has happened in terms of internal and external pressure and the kinetic molecular theory.


I have a small idea but am not sure of it.

2007-04-23 09:17:56 · 1 answers · asked by MaryJAyJay 2

Choose from the following for questions 1-3:
A. a solution with a pH = 7
B. a solution with a pH < 7, which is not a buffer
C. a solution with a pH < 7, which is a buffer
D. a solution with a pH > 7, which is not a buffer
E. a solution with a pH > 7, which is a buffer

Ionization Constants:
HCOOH Ka = 0.00018
CH3NH2 Ka = 0.00044
H3PO2 Ka1 = 0.03 Ka2 = 0.00000017

Questions:
1. A solution with an initial HCOOH concentration of 1 M, and an initial K2HPO2 concentration of 1 M.
2. A solution with an initial H3PO2 concentration of 1 M, and an initial KH2PO2 concentration of 1 M.
3. A solution with an initial CH3NH2 concentration of 1 M, and an initial CH3NH3Cl concentration of 1 M.


(I think 2 is C and 3 is E, but I'm not sure)

2007-04-23 09:10:38 · 1 answers · asked by delilah 2

Based on the readings in your text, which of the following are true statements ?



a) beta-particle emission increases the mass number of the
parent nucleus by one unit


b) During beta-particle emission from a nucleus, a neutron is converted
to a proton


c) In the nuclear process known as electron capture, the atomic number remains constant
&nbps while the mass number decreases by one unit


d) Alpha radiation is by far the most harmful type of radiation to living tissue


e) Based on the number of protons and neutrons, we would expect sodium-23 to be an unstable isotope

2007-04-23 08:36:56 · 2 answers · asked by Anonymous

From this fact alone, obtain the the signs of H° and S°, assuming that H° and S° do not change much with temperature.

N2(g) + 3 H2(g) 2 NH3(g)

H°
positive
negative

S°
positive
negative
Explain your reasoning.

2007-04-23 07:38:23 · 2 answers · asked by Anonymous

2 HIg) + Cl2(g) 2 HCl(g) + I2(s)

Calculate the following values for the reaction above.

(a) H° = kJ
(b) S° = J/K
(c) G° = kJ

(d) Calculate G° at 25° using the Gibbs-Helmholtz equation.
kJ

(e) Describe the reaction in the forward direction. (Select all that apply.)

endothermic
exothermic
entropy increases
entropy decreases
spontaneous
nonspontaneous

2007-04-23 07:32:57 · 2 answers · asked by Anonymous

Are Nonmetals located on the right side and at the center of the periodic table?

2007-04-23 06:51:38 · 4 answers · asked by Anonymous

2007-04-23 06:45:07 · 24 answers · asked by Anonymous

any reaction, state why.

(a) 2 SO3(g) 2 SO2(g) + O2(g)

positive
negative
not predictable

(b) C2H5OH(l) + 3 O2(g) 2 CO2(g) + 3 H2O(l)

positive
negative
not predictable


(c) P4(g) P4(s)
positive
negative
not predictable


(d) 2 NaHCO3(s) Na2CO3(s) + H2O(g) + CO2(g)
positive
negative
not predictable

2007-04-23 06:20:07 · 3 answers · asked by l_walker2005 1

How do you polymerize butanol and what is the polymer that is produced by this reaction. Also what sort of polymerization reaction is it.

2007-04-23 05:19:14 · 6 answers · asked by cara g 1

NOTE: Read the equations left to right

a) H2PO4 − + H2O ↔ HPO4 2− + H3O + H2PO4 &minus is the Lewis acid


b) HClO4 + H2O → H3O + + ClO4 − HClO4 is the Lewis base


c) H2PO4 − + H2PO4 − ↔ H3PO4 + HPO4 2− H2PO4 &minus is both the Lewis base and the Lewis acid


d) HCl + H2O → H3O + + Cl − Water is the Lewis base


e) Fe(H2O)6 3+ + H2O ↔ Fe(H2O)5(OH) 2+ + H3O + Fe(H2O)6 3+ is the Lewis acid

2007-04-23 04:13:48 · 1 answers · asked by xoblake13xo 1

if you have answer for the previous question , can you help me for the followings as well ?

1 . test that distinguish primary alcohol from secondary ;
2 . test that shows the presence of carboxylic acid ;

thanks

2007-04-23 02:43:10 · 1 answers · asked by livefast_dieyoung 2

i am looking for some simple lab test ?

2007-04-23 02:37:21 · 2 answers · asked by livefast_dieyoung 2

I have a question I don't understand.

It says that

-Scandium with 24 neutrons and 21 electrons is neutral
-Rhodium with 45 protons and 45 electrons isn't neutral.

I thought that neutral atoms have equal numbers of protons and electrons, so I can't understand!!!
I have a big Science test today, so please explain why!!
(English isn't my first language)

2007-04-23 02:32:18 · 2 answers · asked by Sayaka 1

a beaker of water is heated. The water from the salt solution evaporates and changes from a liquid to a gas. when all water evaporated, solid salt remains in the evaporating dish?

2007-04-23 02:16:28 · 2 answers · asked by Anonymous

A hydrocarbon C14H12 contains 93.33% carbon and 6.67% hydrogen by mass.
The hydrocarbon has 2 structural isomers, W and X that contains 2 benzene rings respectively. W exhibits geometrical isomerism but X does not. In their reaction with HBr, W forms Y that is optically active, while X forms Z that is optically non-active. Determine the structure of W, X, Y, and Z.

Can you guys please teach me how to elaborate on ways to determine W, X, Y, and Z?

2007-04-23 02:07:39 · 3 answers · asked by Adrianne G. 2

a. What two changes would be observed when acidified potassium manganate (VII) is added to aqueous hydrogen peroxide?

b. Why is tin recycled?

c. What is the balanced equation for the thermal decomposition of tin (IV) chloride. Why can this decomposition be described as a redox reaction?

2007-04-23 01:58:09 · 4 answers · asked by Anonymous

hi
is there any use for the waste gas of nitrogen from the blast furnace?

2007-04-23 01:52:36 · 2 answers · asked by blubbablub 1