chemistry problems questions
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Hi there, your question is incomplete.
Please mention what topic exactly you want me to answer. Since the question isn't complete, I am going to put some basic chemistry problems of class X
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Balancing equation
Problem #1:
FeCl3 + MgO ---> Fe2O3 + MgCl2
Solution:
1) Balance the Cl (note that 2 x 3 = 3 x 2):
2FeCl3 + MgO ---> Fe2O3 + 3MgCl2
The Fe also gets balanced in this step.
2) Pick either the O or the Mg to balance next:
2FeCl3 + 3MgO ---> Fe2O3 + 3MgCl2
The other element (Mg or O, depending on which one you picked) also gets balanced in this step.
Problem #2:
Li + H3PO4 ---> H2 + Li3PO4
Solution:
1) Balance the Li:
3Li + H3PO4 ---> H2 + Li3PO4
2) Now, look at the hydrogens. See how the H comes only in groups of 3 on the left and only in groups of 2 on the right? Do this:
3Li + 2H3PO4 ---> 3H2 + Li3PO4
Remember 2 x 3 = 6 and 3 x 2 = 6. It shows up a lot in balancing problems (if you haven't already figured that out!).
3) Balance the phosphate as a group:
3Li + 2H3PO4 ---> 3H2 + 2Li3PO4
4) Oops, that messed up the lithium, so we fix it:
6Li + 2H3PO4 ---> 3H2 + 2Li3PO4
Problem #3:
ZnS + O2 ---> ZnO + SO2
1) Balance the oxygen with a fractional coefficient (Zn and S are already balanced):
ZnS + (3/2)O2 ---> ZnO + SO2
2) Multiply through to clear the fraction:
2ZnS + 3O2 ---> 2ZnO + 2SO2
Problem #4:
FeS2 + Cl2 ---> FeCl3 + S2Cl2
Solution:
See how the Fe and the S are already balanced? So, look just at the Cl. There are a total of 5 on the right-hand side, so we put 5 on the left:
FeS2 + (5/2)Cl2 ---> FeCl3 + S2Cl2
Clear the fraction by multiplying through by 2:
2FeS2 + 5Cl2 ---> 2FeCl3 + 2S2Cl2
Problem #5:
Fe + HC2H3O2 ---> Fe(C2H3O2)3 + H2
Solution:
1) Balance the acetate:
Fe + 3HC2H3O2 ---> Fe(C2H3O2)3 + H2
2) Balance the hydrogen:
Fe + 3HC2H3O2 ---> Fe(C2H3O2)3 + (3/2)H2
3) Clear the fraction:
2Fe + 6HC2H3O2 ---> 2Fe(C2H3O2)3 + 3H2
Problem #6:
H2(g) + V2O5(s) ---> V2O3(s) + H2O(ℓ)
Solution:
1) Balance the oxygen:
H2(g) + V2O5(s) ---> V2O3(s) + 2H2O(ℓ)
2) Balance the hydrogen:
2H2(g) + V2O5(s) ---> V2O3(s) + 2H2O(ℓ)
Note that the vanadium was not addressed because it stayed in balance the entire time. Note how the hydrogen started out balanced, but the balancing of oxygen affected the hydrogen, which we addressed in the second step.
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I.U.P.A.C naming and Organic Chemistry
The hybridization of carbon atoms in alkanes is
(a) sp
(b) sp2
(c) sp3
(d) sp3d
(e) sp3d2
A molecule with the formula C3H8 is a(n):
(a) hexane
(b) propane
(c) decane
(d) butane
(e) ethane
The general formula for noncyclic alkenes is:
(a) CnH2n+2
(b) CnH2n
(c) CnH2n-2
(d) CnHn+2
(e) C n H n
How many actual double bonds does the benzene ring possess?
(a) None, carbon-carbon bonds in benzene are delocalized around the ring
(b) 1 double bond
(c) 2 double bonds
(d) 3 double bonds
(e) 4 double bonds
Para-xylene is the same as:
(a) 1,2-dimethylbenzene
(b) 1,3-diethylbenzene
(c) 1,3-dimethylbenzene
(d) 1,4-diethylbenzene
(e) 1,4-dimethylbenzene
Which of the following formulas represents an alkene?
(a) CH3CH2CH3
(b) CH3CH3
(c) CH3CH2CHCH2
(d) CH3CH2Cl
(e) CHCH
Which one of the following is a secondary alcohol?
(a) CH3CH2OH
(b) CH3OH
(c) CH3CH(OH)CH3
(d) (CH3)C3OH
(e) none of these
Select the IUPAC name for: (CH3)2CHCH(OH)CH2C(CH3)3.
(a) 2,5,5-trimethyl-3-hexanol
(b) 1,1,4,4-pentamethylbutanol
(c) 1,1-dimethylisopentanol
(d) 2,5-dimethyl-4-hexanol
(e) none of these
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Ch-3 Class X CBSE
Metals and Non- Metals
Some important short answer questions are attached in the question.
-source Byj us
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