1.All of the following statements about sodium acetate are true except:
(A) It is an ionic compound
(B) it is soluble in water
(C) contains carbon
(D) it is also called vinegar
(E) if dissolved in water the solution has a pH > 7
2. All of the following statements about NaBH4 are true except:
(A) it is used in organic chemistry synthesis
(B) it is a reducing agent
(C) by the catalytic decomposition of its aqueous solution, H2 is released
(D) contains 16.66 % Na in molar percent
(E) is a liquid at room temperature
3. Questions 3-6 refer to the following substances
(A) B
(B) Al
(C) Na
(D) Zn
(E) C
3. It is the main constituent of fullerenes
(A) B
(B) Al
(C) Na
(D) Zn
(E) C
4.It is an alkali metal
(A) B
(B) Al
(C) Na
(D) Zn
(E) C
5.The hydroxide of which of the following elements is acidic if dissolved in water
(A) B
(B) Al
(C) Na
(D) Zn
(E) C
6.It is a transitional element:
(A) B
(B) Al
(C) Na
(D) Zn
(E) C
7.Consider the following electronic configuration 1s2 2s2 2p6 3s2 3p6 4s2
The compound formed by this element with oxygen has the formula:
(A) MO
(B) MO2
(C) M2O
(D) M2O2
(E) M2O3
8.Consider the following acid : H3PO2.Which of the following is true?
(A) it is a monoprotic acid
(B) it is a diprotic acid
(C) it is a triprotic acid
(D) does not exist
(E) it does not present acidic properties
9.The Ksp of PbSO4 is 1x 10 ^ -8. the solubility of PbSO4 is:
(A) 10^-8
(B) 10^-1
(C) 10^-2
(D) 10^-4
(E) 10^-16
10.Which of the following bonds is intermolecular ?
(A) ionic bond
(B) covalent bond
(C) metallic bpnd
(D) hydrogen bond
(E) None of them
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13 comments:
on #1, if it was HC2H3O2, then pH<7 rite?
#2-wats that compound called
-how are you supposed to know
all that stuff about it?
-how does it have 16.66% molar%;
I got like 60 something %
#4-how is Na an alkaline and not an
alkali metal?
#5-how are you supposed to know its
Boron that gives an acidic
hydroxide?
#8-how is H3PO2 monoprotic and not
triprotic?
#10-how is hydrogen bonding
intermolecular? i thought it
occurs between an element and
hydrogen..which would be
intramolecular..
hehe, i know these are a lot of questions, so i'm sorry and i'm not expecting the answers rite away..i just wanna make sure i know everything i need to know to get a 5 on the AP exam ..
Ok.
#1-yes if it was CH3COOH the pH would have been < 7. However CH3COONa is a strong base with a pH > 7.
#2-the compound is called Sodium borohydride
If you did some organic chemistry you would have known the answer at the first 2 questions because NaBH4 appears quite often in organic synthesis as reducing agent.
You could guess that in aqueous solution it releases hydrogen because of its high content of Hydrogen (Assuming that you have never seen the reaction) .
the molar percent is expressed as number of moles of Na over the total numbers of moles- numbers of atoms of Na over the total number of atoms- i.e. 1/6 (6=1 Na+ 1 B + 4H).
And you remain with the last choice that should be wrong.
this was indeed a though question.
#4 yes it is an alkali metal, alkaline metals does not exist, only alkaline earth.I was thinking somewhere else probably, anyway I've modified it, thanks.
#5 from the inorganic lecture, i guess. However, you could eliminate all others choices because they were obviously wrong and you could pick up this one.
#8 An acid is called monoprotic or poliprotic accordingly to how many hydrogens can donate, not how many hydrogens does it have.Ig you draw the Lewis structure you see that it has only one hydrogen that can be donated-the one bounded to the oxygen.The other 2 are directly bounded to the P and the can not be donated.
# 10 it occurs between an element and a hydrogen FROM TWO DIFFERENT molecules. In water H-O-H the hydrogen bonding is not the H-O bond, but a new bond formed between the H from one molecule of water and the O from another molecule of water.
H-O-H.....OH2.
The hydrogen bond is the dotted line.
Sodium borohydride is the formal name.
The IUPAC nomenclature is sodium tetrahydroborate.
ok, so do metals form basic solutions and nonmetals form acidic solutions ?
and for #8-is the structure like this?
O
|
H-P-O-H
|
H
..O
..|
H-P-O-H
..|
..H
sorry i tried to do it w/o the dots..just ignore them .. but is that the structure?
The structure is :
P double bonded to an oxygen, simple bonded with 2 hydrogen atoms and an OH group.
H
\
H-P=O
/
HO
ok thx, and so do metals form basic solutions and nonmetals form acidic solutions?
Metal oxides form basic solutions while nonmetal oxides form acidic solution.
Metal hydroxides are usually basic, but you can not say something about nonmetal hydroxides because they are defined only for few elements.
how do you find the answers to these tests to check?
Hello
can u plz give the answers 2 these questions? i want 2 check if i got them right......thx.
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