chem question - answer them if u think ur smart; (1 Viewer)

[gebey]

HERE :

SOME SIMPLE CHEM QUESTION:

1. Identify the ions present in an aqueous LiOH solution.

2. How many moles of oxygen are there in 10.46g SO<SUB>2</SUB> ?

3. What is the percent by mass of nitrogen N<SUB>2</SUB>O<SUB>3</SUB> ?

4. A compound has 40.9% Carbon, 4.58% Hydrogen and 54.5% Oxygen. The molecular mass was found to be 88.1. What is the molecular formula ?

5. What mass of magnesium sulfate must be dissolved in water to prepare 810 mL of 0.420 M MgSO<SUB>4</SUB> solution ?

6. What volume of 0.330 M HCl solution would be required to prepare 520 mL of 0.00790 M HCl solution ?

7. Select the spectator ions for the following reaction.

AgNO<SUB>3</SUB>(aq) + NaCl(aq)

AgCl(s) + NaNO<SUB>3</SUB>(aq)​

<TABLE cellSpacing=0 cellPadding=4 width="95%" bgColor=#9999ff border=3><TBODY><TR><TD class=questitem width="5%" bgColor=#9999ff>A</TD><TD class=questitem><BASEFONT>Ag<SUP>+</SUP>(aq), Cl<SUP>-</SUP>(aq) </BASEFONT></TD></TR><TR><TD class=questitem width="5%" bgColor=#9999ff><CENTER><INPUT type=submit value=" B " name=R6Y2B></CENTER></TD><TD class=questitem><BASEFONT>Na<SUP>+</SUP>(aq), NO<SUB>3</SUB><SUP>-</SUP>(aq) </BASEFONT></TD></TR><TR><TD class=questitem width="5%" bgColor=#9999ff><CENTER><INPUT type=submit value=" C " name=R632C></CENTER></TD><TD class=questitem><BASEFONT>Ag<SUP>+</SUP>(aq), NO<SUB>3</SUB><SUP>-</SUP>(aq) </BASEFONT></TD></TR><TR><TD class=questitem width="5%" bgColor=#9999ff><CENTER><INPUT type=submit value=" D " name=R642D></CENTER></TD><TD class=questitem><BASEFONT>Na<SUP>+</SUP>(aq), Cl<SUP>-</SUP>(aq) </BASEFONT></TD></TR></TBODY></TABLE>

8. When balanced, the coefficient of O<SUB>2</SUB> in the following equation is:

__ C<SUB>2</SUB>H<SUB>4</SUB> + __ O<SUB>2</SUB>

__ CO<SUB>2</SUB> + __ H<SUB>2</SUB>O
​

9. What is the theoretical yield of vanadium that can be produced by the reaction of 40.0 g of V<SUB>2</SUB>O<SUB>5</SUB> with 40.0 g of calcium, based on the following chemical reaction?
​

V<SUB>2</SUB>O<SUB>5</SUB>(s) + 5Ca(l)

2V(l) + 5CaO(s)
​

10. If Hg and 2.30g O<SUB>2</SUB> are obtained from heating 65.0g HgO, what is the mass percent yield of O<SUB>2</SUB> ? Hint work out the stoichiometry of the reaction first.​

 

[Ea22.007]

lets see ill try,

1. Li+, OH-, H+
2. 0.33 mol of O atoms
3. 36.9%
4. C3H4O3
5. 40.95 g
6. 12.5 mL
7. B
8. 3
9. 462.37 g
10. 7.4%

 

[aussiechica7]

omgosh icb u just posted your hw on bos.

and that someone answered it for u.

do your own work!!!

 

[Eddyah]

My answers:
1) Li+ OH-
2) 0.16 moles of O2 gas (presuming it cant exist on its own)
3) 36.8%
4) C3H4O3
5) 62.427gs
6) 12.44mL
7) B
8) 3
9) 22.40gs
10) I LOVE YOU TEACHER LADY/MAN MARKING THIS ANSWER!

 

[Lucid Scintilla]

omgosh icb u just posted your hw on bos.

and that someone answered it for u.

do your own work!!!

But she's [supposedly a she, according to profile] done her HSC [supposedly done, according to profile].
What the random?

1. Identify the ions present in an aqueous LiOH solution.

1. Li+, OH-, H+

I don't know why you have a hydrogen ion there...

2. How many moles of oxygen are there in 10.46g SO2 ?

2) 0.16 moles of O2 gas (presuming it cant exist on its own)

O₂ is a diatomic covalent molecule; it is 'elemental' oxygen. Cannot exist otherwise, on its own. O₃ is ozone, of course.

3. 36.85872138911%
2(14.01)/{3(16) + 2(14.01)}
I suppose Ea22.007 is right in rounding it up.

 

[kony]

question to number one... if u want to be really pedantic you could chuck in hydronium and hydrogen ions.

 

[Ea22.007]

i had the H+ coz i considered that H20 would dissociate to a certain amount in any solution and it asked for all the ions im presuming so unless all the H+ reacted with the OH- in solution from the LiOH then there should be some H+ in there somewhere shoudlnt there?

 

[aussiechica7]

oops she.

ok well she could b doing 1st yr chem 4 all we know

anyway sry if i jumped the gun a bit there

 

[Lucid Scintilla]

question to number one... if u want to be really pedantic you could chuck in hydronium and hydrogen ions.

Yes, you could... but seriously, ...

It depends at what level of Chemistry you're doing then.

i had the H+ coz i considered that H20 would dissociate to a certain amount in any solution and it asked for all the ions im presuming so unless all the H+ reacted with the OH- in solution from the LiOH then there should be some H+ in there somewhere shoudlnt there?

Okay.

oops she.

ok well she could b doing 1st yr chem 4 all we know

anyway sry if i jumped the gun a bit there

Indeed.