Chemistry - October 2007

2007-10-03 08:33:10 · 3 answers · asked by ? 3

Please explain this. We had a test, i made a tremendousy terrible grade on it. We got to correct our answers, and make a study guide based on the test. I don't know how to explain these.



~~An element has the electron configuration [Kr] 4d10 5s2 5p2. The element is a?



It's a metal, but how do i explain the differences in groups --noble gas, metal, nonmetal, etc.??

~~The electron configuration for Cr2+ is...

The answer is [Ar]3d4


I keep getting [Ar] 4s2 3d2... what am i doing wrong?

Last one, for now.

~~ Which of the following frequencies corresponds to light with the longest wavelength?

The answer is either 4.12 x 10 5 s-1

Or 3.00 x 10 3 s-1



How do you find it?



Thank you, if i have any help.

2007-10-03 07:59:48 · 1 answers · asked by ღ❤Crystal❤ღ 4

Why does sulphur powder react slowly with silver metal, but sulphide ions react quickly to form a precipitate with silver ions? Does it have to do with the states (solids vs. ions) or surface area?

2007-10-03 07:43:42 · 1 answers · asked by Jeff P 3

2007-10-03 07:36:37 · 3 answers · asked by Anonymous

Calculate the concentration in molarity of a NaOH solution if 10 mL of the solution are needed to neutralize 21 mL of a .312 molar HCl solution?

2007-10-03 07:30:52 · 2 answers · asked by wasabi makes the world go round 1

a peice of metallic Sn were placed in distilled water w/ metallic Zn? Explain? Write net ionic eq.

2007-10-03 07:27:03 · 1 answers · asked by PiNk-PrInCeSs 3

copper (II) oxide is reduced by hydrogen to copper and water:

CuO + H2 ---> Cu + H2O

What mass of copper(II) oxide will be reduced by excess hydrogen to give 16g of copper.

do i need to do:

mass = moles x molar mass?

thanks

2007-10-03 07:12:10 · 2 answers · asked by Anonymous

the equation balanced is (sorry about big numbers, they dont do small ones)

2AL(OH)3 + 3H2SO4 = AL2(SO4)3 + 6H2O

This is for As level chemistry. I had a go but the number appeared to be too big

2007-10-03 05:47:36 · 2 answers · asked by Anonymous

1. What is the 1,1-dimethylethyl group, -C(CH3)3, can also be called?

2. how many methine groups are there in isopropylcyclopentane?

3. What is the total # of constitutional isomers with the formula C5H12?

Detals, please

2007-10-03 05:46:25 · 2 answers · asked by Anonymous

out of these choices
H2O
NaCl
CH1

2007-10-03 05:30:27 · 1 answers · asked by tc 1

ch3 ch2 ch2 ch2 oH
+
H+
1-Butanol + hydrogen = ?????

2007-10-03 04:01:51 · 2 answers · asked by alexander i 1

Guys can you help me out?

What would the chemical equation be for:

placing magnesium metal over a flame. Make bright light, turns to ash.

CuSO4. 5H2O is heated.

A bit of potassium chlorate is placed in a test tube and heated. Glowing splint is inserted.

Just the chemical equations, please!

Thanks!
-Stan

2007-10-03 03:54:41 · 1 answers · asked by stan k 1

2007-10-03 03:52:21 · 2 answers · asked by Anonymous

a hydrate of sodium phosphate contains 49.7% water by weight.

a) how many grams of water and how many grams of anhydrous Na3PO4 are in 1000. grams of this sample?

b) In this same 1000. gram sample, how many moles of water and how many moles of anhydrous Na3PO4 are present.

c. What is the formula of the hydrate?

(i need the computation for fully understanding) thanks

2007-10-03 03:50:03 · 2 answers · asked by semi_sonic18 1

1. What volume of 0.2 M Fe(NO3)3 is needed to make 50 mL of 0.002 M Fe(NO3)3?
2. WHat are the concentrations of Fe+3 and NO-3 in a 0.2 M Fe(NO3)3 solution?
3. If 5 mL 0,002 M Fe(NO3)3 is mixed with 5 mL 0.002 M KSCN calculate the initial concentration of Fe+3 and SCN- in the solution

2007-10-03 03:37:17 · 2 answers · asked by Anonymous

I have been asked to draw lowest energy conformer of 4-tert-butylcyclohexanone and to mark whether the substituent is an axial or equatorial orientation or neither...
somebody please help..
does this have to be drawn as a newman projection .. im confused. Thank u!

2007-10-03 03:28:06 · 2 answers · asked by Anonymous

2007-10-03 00:46:15 · 1 answers · asked by Anonymous

2007-10-02 22:37:45 · 3 answers · asked by Anonymous

common acids eg. hydrochloric acids, sulphuric acid, nitric acid, ethanoic acid etc.

2007-10-02 21:53:12 · 6 answers · asked by andrea 1

2007-10-02 21:48:36 · 1 answers · asked by lee anna 2

The volume of a sample of argon gas is 138 mL at -150°C and 1 atm. Predict the volume of the sample at +150°C and 1 atm.

___ A. -138
___ B. 276
___ C. 475
___ D. Need more information

2007-10-02 20:23:03 · 3 answers · asked by Anonymous

What is the balanced chemical equation for the net ionic reaction that occurs when acetic acid is mixed with nitric acid?

2007-10-02 19:15:59 · 3 answers · asked by Erick T 1

Name Each Covalent Compound:
A. HgCl2
B. IF5
C. N2O5
D. Cl2O
E. HgS
F. PCl5

2007-10-02 19:06:43 · 3 answers · asked by Happy Killa Pants 2

How many grams chlorine are in 300. mL seawater if density of seawater is 1.025 g/mL?

2007-10-02 19:00:03 · 2 answers · asked by Anonymous

Give the empirical formula for the binary compound formed by the most common monatomic ions formed by each pair of elements:
A. zinc and sulfur
B. barium and iodine
C. magnesium and chlorine
D. silicon and oxygen
E. sodium and sulfur

2007-10-02 18:36:44 · 2 answers · asked by Happy Killa Pants 2

Predict the charge on the most common monatomic ion formed by each element:
A. Cl
B. P
C. Sc
D. Mg
E. As
F. O

2007-10-02 18:35:11 · 3 answers · asked by Happy Killa Pants 2

I am horrible at math and my job is getting me behind in my chemistry. can in one help with the following questions.

1.Calculate the volume of 2.50 moles of zinc, assuming the density of the metal to be 7.14 g/cc.

2.Calculate the volume of 1.25 moles of magnesium, assuming the density of the metal to be 1.74 g/cc.

2007-10-02 18:29:17 · 1 answers · asked by scott c 1

2007-10-02 18:26:24 · 7 answers · asked by Burnt Toast 1

I need help...can't figure it out...

2007-10-02 18:07:53 · 2 answers · asked by .Cami.B. 2

3.An atomic gas absorbs red light of wavelength 653 nm


What is the energy difference (kJ) between the two quantum states involved in the absorbtion ?

4.If a certain source emits radiation of wavelength 355. nm what is the energy, in kJ, of one mole of photons of this radiation?

2007-10-02 17:56:26 · 1 answers · asked by Sadie G 1