Chemistry - September 2007

Why is Acetic Acid's molar mass twice what it should be when in CCl4 or benzene solution?

Can someone explain why this ocurres?

2007-09-27 05:47:13 · 1 answers · asked by Carolina 4

18. in going from right to left in any given row in the periodic table, the size of atoms generally __.
A. increases B. decreases C. stays the same D. changes randomly

19. compared to the neutral atom from which it is derived, a negative ion is __.
A. always larger B. always smaller C. larger in some cases and smaller in others D. the same size

20. transition elements, such as chromium, are likely to have __.
A. an oxidation number of 1+
B. an oxidation number of 2+
C. multiple oxidation numbers
D. a negative oxidation number

21. a metallic ion is __ its corresponding atom.
A. larger than
B. smaller than
C. the same size
D. impossible to compare with

22. ionic radii __ down a group in the periodic table.
A. increase B. decrease C. stay the same D. follow no pattern

23.alkaline earth metals lose __ electrons to achieve the electron configuration of the noble gas in the preceding period.
A. one B. two C. six D. seven

2007-09-27 05:36:38 · 2 answers · asked by Anonymous

11. an element is in group 15. the last electron added to an atom of this element will be in a(n) __ sublevel.
A. s B. p C. d D. f

12. an atom is in group 2, period 3. how many electrons does the atom contain?
A. 2 B. 3 C. 5 D. 12

13. which is a possible last sublevel for an element found in group 18?
A. 3p6 B. 4s2 C. 4p3 D. 4d8

14. an element is most likely to have properties similar to those of __.
A. another element in the same period
B. another element in the same group
C. a noble gas
D. a transition element

15. transition elements have final electrons in the __ sublevel.
A. s B. p C. d D. f

16. what are the valence electrons in the electron configuration of tin, [Kr] 4d105s25p2?
A. [Kr] B. 4d10 C. 5s25p2 D. 5p2

17. each row in the periodic table ends with a __.
A. metal B. nonmetal C. metalloid D. noble gas

2007-09-27 05:31:35 · 1 answers · asked by Anonymous

Indicate whether the sentence or statement is A) true or B) false for 1-8.

1 atoms form bonds in such a way as to produce the electron configuration of noble gas.

2 cesium is an example of an element with a high electronegativity.

3 the shielding effect would be greater in an atom of chlorine than in an atom of fluorine.

4 conductivity in metals can be explained by what is called a sea of electrons.

5 all diatomic molecules are linear.

6 the maximum number of electrons in any p sublevel is six.

7 the maximum number of electrons in any f sublevel is 18.

8 in general, the closer an orbital is to the nucleus. the more energy an electron possesses.

9 which of the following orbitals is closes to the nucleus?
A. 1s B. 2p C. 4s D. 3d

10 compare the maximum number of electrons possible in sublevel 3d with the maximum number that could be in sublevel 4d.
A they are the same
B there are more in 3d
C there are more in 4d
D they are impossible to comare

2007-09-27 05:25:32 · 3 answers · asked by Anonymous

Distinguish the following items:
(a) Hydrolysis of salts and electrolysis
(b) Acid strength and acid concentration
(c) Neutralization point and titration end point
This is my homework... But I don't know how to answer them... So anyone can help?

2007-09-27 04:49:53 · 1 answers · asked by Someone Secretly Hidden 1

3NO2 + H2O -> 2HNO3 + NO

If 74g of NO2 reacts with 100 g H20, 23 g gaseous NO are made. Calculate % yield.

Find Limiting Reagent
74 g NO2 (1 mole NO2 / 46 g NO2) = 1.61 mole NO2
100 g H2O (1 mole H2O / 18.02 g H2O) = 5.55 mole H2O
NO2 is the LR

Convert mole NO2 to g NO
1.61 mole NO2 (1 mole NO / 3 mole NO2) = 0.54 mole NO
0.54 mole NO (30 g NO / 1 mole NO) = 16.1 g NO

Percent Yield
23 g NO / 16.1 g NO * 100% = 142.9%

THE SECOND ONE IS
3NO2 + H2O -> 2HNO3 + NO

If 2.2 kg of NO2 reacts with 1.2 kg H2O, 0.23 kg gaseous NO are made. Calculate % yield.

Find LR
2200 g NO2 (1 mole NO2 / 46 g NO2) = 47.8 mole NO2
1200 g H2O (1 mole H2O / 18.02 g H2O) = 66.6 mole H2O
NO2 is the LR

Convert mole NO2 to g NO
47.8 mole NO2 (1 mole NO / 3 mole NO2) = 15.9 mole NO
15.9 mole NO (30 g NO / 1 mole NO) = 477 g NO

Percent Yield
230 g NO / 477 g NO * 100% = 48.2%

ty for your help!

2007-09-27 04:13:33 · 2 answers · asked by Saegis 2

You are confronted with the following question: One mole of an ideal gas is sealed in a 22.4- L container at a pressure of 1 atm and a temperature of 273 K . The temperature is then increased to 305 , but the container does not expand.

also what is the appropriate formula to solve this problem

2007-09-27 04:11:06 · 3 answers · asked by Anonymous

I have no idea...do you?

2007-09-27 03:34:21 · 4 answers · asked by Caramel 2

24. balance the equation Sr(s) + H2O(l) --> Sr(OH)2(aq) + H2(g).

A. Sr(s) +2H2O(l) --> Sr(OH)2(aq) + H2(g)
B. Sr(s) +2H2O(l) --> Sr(OH)2(aq) + 2H2(g)
C. Sr(s) +3H2O(l) --> Sr(OH)2(aq) + 3H2(g)
D. it is already balanced

25. lithium metal reacts with ammonia gas to form hydrogen gas and crystals of lithium amide, LiNH2. write a balanced chemical equation for this reaction, and classify the reaction as one of the five major types.

A. 2Li(s) + 2NH3(g --> 2LiNH2(s) +H2(g); decomposition
B. Li(s) + 2NH3(g) --> LiNH2(s) + 4H(g) ; synthesis
C. 2Li(s) + 2NH3(g) --> 2LiNH2(s) +H2(g) ; single displacment
D. 4Li(s) + 4NH3(g) --> 4LiNH2(s) + H2(g) ; double

2007-09-27 03:20:49 · 2 answers · asked by Anonymous

KOH or NH3... those are the two choices, help me!!!

2007-09-27 03:20:11 · 5 answers · asked by Dan S 1

2007-09-27 03:16:47 · 3 answers · asked by cmpunkbohemia 1

2007-09-27 03:15:12 · 2 answers · asked by cmpunkbohemia 1

20. the definition of a chemical reation is
A. two chemicals with opposite atoms
B. a chemical with inner electrons
C. any chemical change
D. both a & c

21. fid the equation that is correctly balanced:
A. 2Hl(aq) + 2Pb(NO3)2(aq) --> Pbl2(s) +2HNO3(aq)
B. 2Hl(aq) + Pb(NO3)2(aq) --> Pbl2(s) +2HNO3(aq)
C. Hl(aq) + 3Pb(NO3)2(aq) --> 3Pbl2(s) +2HNO3(aq)
D. 3Hl(aq) + Pb(NO3)2(aq) --> 3Pbl2(s) +2HNO3(aq)

22. find the equation that is correctly balanced:
A. H2SO4(aq) + BaCl2(aq) --> HCl(aq) + 2BaSO4(s)
B. 2H2SO4(aq) + 2BaCl2(aq) --> 4HCl(aq) + BaSO4(s)
C. H2SO4(aq) + 2BaCl2(aq) --> 2HCl(aq) + 2BaSO4(s)
D. H2SO4(aq) + BaCl2(aq) --> 2HCl(aq) + BaSO4(s)

23. write a balanced chemical equation for the reaction described: aluminum metal + hydrochloric acid aluminum chloride solution + hydrogen.
A. Al(s) + 3HCl(aq) --> AlCl3(aq) + 3H2(g)
B. 2Al(s) + HCl(aq) --> 2AlCl3(aq) + H(g)
C. 2Al(s) + 6HCl(aq) --> 2AlCl3(aq) + 3H2(g)
D. 4Al(s) + 12HCl(aq) --> 4AlCl3(aq) + 3H(g)

2007-09-27 03:14:02 · 2 answers · asked by Anonymous

calculate molality and molarity.
Molar mass of H2SO4 is 98g/mol.
plz solve this problem and plz explain what does 15%H2SO4 means.

2007-09-27 02:59:42 · 5 answers · asked by cmpunkbohemia 1

2007-09-27 02:54:34 · 1 answers · asked by lasmom1223 1

1. the properties of a compound are __ the properties of the elements that form it.
A. similar to
B. different from
C. identical to
D. derived from

2. reactions between atoms involve only __.
A. valence electrons
B. inner electrons
C. neutrons
D. protons

3.oppositely charged ions attract each other, forming a(n) __ bond.
A. covalent
B. crystal
C. ionic
D. molecular

4. the formula for iron (lll) oxide, Fe2Cl3, shows that one unit of the compound contains __ iron atoms.
A. 2
B. 3
C. 5
D. 6

5. two atoms of bromine react with each other to form a(n) __ bond.
A. covalent
B. ionic
C. crystal
D. molecular

6. noble gases are sometimes used to protect valuable documents because they are __.
A. molecular
B. totally inert
C. unreactive
D. unstable

7.when reacting with an atom of fluorine, an atom of lithium will lose an electron and become a lithium __.
A. compund
B. crystal
C. ion
D. molecule

2007-09-27 02:49:57 · 3 answers · asked by Anonymous

When its..

is poured onto another substance
mixes with water
dissolves another substance
or
changes from one state of matter to another

2007-09-27 02:46:35 · 1 answers · asked by Anonymous

Why can samples of solutions often be separated into their compenents by chromatography?


I'm not sure how to explain this. Can anyone help PLEASE thanks sooo much!!!

2007-09-27 02:38:43 · 4 answers · asked by Natlsn12009 1

2007-09-27 02:35:24 · 1 answers · asked by Anonymous

Water "softeners" remove metal ions such as Fe2+, Fe3+, Ca2+, and Mg2+ (which make water "hard") by replacing them with enough Na+ ions to maintain the same number of positive charges in the solution. If 6.5 103 L hard water is 0.015 M Ca2+ and 0.0010 M Fe3+, how many moles of Na+ are needed to replace these ions?

2007-09-27 02:34:42 · 1 answers · asked by ronnie c 1

I mean,we add those numbers that we put in front of each element to balance the equation,for example the reactants,the sum of the numbers that we put to balance the equation is 5,and for the product is 4,,,why?but without multiplying it only adding those numbers...

2007-09-27 02:30:47 · 1 answers · asked by Anonymous

2007-09-27 02:17:34 · 1 answers · asked by Anonymous

Truthfully!

2007-09-27 02:13:20 · 28 answers · asked by MuffDvr 3

2007-09-27 02:05:05 · 1 answers · asked by Shival G 1

2007-09-26 19:14:16 · 4 answers · asked by Anonymous

P4(s) + 6 Cl2(g) --> 4 PCl3(l)
If the reaction proceeds in 65% yield, how many grams of P4 are required if 137.5 grams of PCl3 are desired?

2007-09-26 18:37:16 · 3 answers · asked by tyler8x6 2

2007-09-26 18:34:44 · 3 answers · asked by Susie 6

2007-09-26 17:58:53 · 4 answers · asked by Kriz S 1

a - A runnning car engine in a closed garage. b- Cooking on a bbq grill indoors with all windows and doors closed.c- Cooking on a propane grill outside. Both A and B...or All listed above

2007-09-26 17:57:16 · 3 answers · asked by WINO86 1

A carbon compound has an empirical formula of CH2O and an approximate molecular weight of 117. What is its molecular formula?

2007-09-26 17:54:35 · 1 answers · asked by tyler8x6 2