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MAD
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MAD
Questions (64)
The solubility of a substance is 12 g per 100 g water at 20 degree , and is 18 g per 100 g water at 60 degree , what is the mass
5 answers
2,074 views
If heat of combustion of acetylene C2H2 is -1301.1 kJ/mol then :
a) Write balanced thermochemical equation of acetylene
5 answers
4,627 views
A) We have an experiment , using the solution of KNO3 , measured freezing point of solution is -1.15 degree , and using a sample
3 answers
933 views
Which of the following pairs are conjugate pairs ?
1) H+ and OH- 2) HCl and Cl- 3) NH2- and NH4+ 4) H2SO4 and SO4^-2 thanks a lot
1 answer
407 views
Which of the following is the conjugate acid to a base in these options :
1) PO4^-3 2) H2O 3) H3PO4 4) H2PO4^-
1 answer
428 views
Which of the following is the conjugate acid to a base in these options :
1) PO4^-3 2) H2O 3) H3PO4 4) H2PO4^-
1 answer
471 views
Find the specific heat of indium , if any one mole absorbs 23 J , when the temperature elevates from 297.5 K to 299.5 K
thank you
1 answer
417 views
The enthalpy change of an endothermic reaction is 8 kJ , and this reaction is spontaneous at 25 oC ,, what is the expected
2 answers
548 views
We have this following gas equilibrium :
H2 + Cl2 <==> 2HCl + 184 kJ then predict the following to know Le chatlier's prediction
2 answers
810 views
Which conditions ( reactant concentration , pressure , and temperature ) elevate high concentration of the underlines in these
3 answers
487 views
If 2.5 * 10^-2 g of Fe(NO3)3 added to 100mL of 1.0 * 10^-4 M NaOH solution , will it produce precipitate ?
thank you
1 answer
421 views
Does it produce precipitate if 1.7 g of AgNO3 and 14.5 g of NaCl solvated in 200 mL water to get a solution in 25 oC ?
thank you
2 answers
703 views
The Ksp of (hydroxyapatite ) Ca5(PO4)3OH is 6.8 * 10^-37 , and its molar concentration is 2.7 * 10^-5 mol/L ,, if this
3 answers
2,150 views
Assume that the ( S ) ( S ; alphabet ) is the solubility in mol/L of AB2 compound , , then what is the concentration of A and B
1 answer
427 views
In relative oxidizing and reducing agents table ;
1) Is Al oxidized by Ni+2 2) Is Cu oxidized by Ag+ 3) Is Pb oxidized by Na+ 4)
2 answers
591 views
In half reaction method of the chemical equation balancing , how about those redox reactions that they don't contain any (H) and
1 answer
489 views
Why the oxidation number of ( H ) is -1 in
1) N2H4 2) CaH2 while ( N ) is different from ( Ca ) ?
5 answers
760 views
Balance the oxidation reduction equation in half reaction
PbO2 + KCl => KClO + KPb(OH)3 thank you a lot
4 answers
2,563 views
I have these equations in our book , but I've tried a few times to solve it in half reaction method , but I couldn't yet :
1)
7 answers
1,087 views
I have trouble finding out the oxidation number of each element in the :
[Cr(N2h4CO)6]4[Cr(CN)6]3
7 answers
1,322 views
A substance contains an element at its probable maximum oxidation number , does this substance have a maximum chance to be an
1 answer
471 views
How many oxidation states Should a substance have at least to undergo Disproportionation reaction ?
thanks
1 answer
407 views
What is the function ( or role ) of platinum in electrochemistry in general ? I read a question about platinum in electric
2 answers
522 views
The standard potential of this cell
Sn|Sn^+2 || Cr^+3|Cr is -0.60 V , what is the reductional standard potential of Cr^+3|Cr ? if
5 answers
688 views
why dry cells are called dry while they contain water ? in electrochemistry
2 answers
919 views
Why does hydrogen electrode have 0.00 V ? or assumed that has 0.00 V ?
1 answer
435 views
Why can't we use water in electrolytic cell during producing aluminium ?
2 answers
463 views
In electrolysis , which reaction does occur on the cathode , half oxidation reaction or reduction ?
2 answers
675 views
Can a substance made of zinc be coated by nickel , using nickel nitrate solution ? How ?
2 answers
820 views
Assuming that this half cell I2 + 2e- + =>2I- as standard electrode and assumed its potential that is 0.00 V :
a) what is
2 answers
489 views
If a nickel rod embedded in a silver nitrate solution , what do we predict ? explain
2 answers
1,055 views
Is these two electrodes appropriate to create a good battery ? :
Cd => Cd^+2 + 2e- and Fe => Fe^+2 + 2e- Explain
1 answer
352 views
Dye of iodine is prepared by dissolving in ethanol , and 1% ( one percent ) of this solution contains 10 g of solute in 1000 g
2 answers
722 views
The solubility of KClO3 in 25 oC is 10 g solute per 100 g water
if 15 g of KClO3 is embedded in 100 g water in 25 oC , then ,
4 answers
3,458 views
Which of the following solutions do they have the maximum osmotic pressure :
1) 0.1 m ( molal conc.) glucose 2) 0.1 m sucrose 3)
3 answers
502 views
We have :
Cl | 1) :B-Cl with two unshared electrons | Cl F | 2) :N-F | F then , if we assume that N and B bind covalently , which
1 answer
442 views
We have this reaction :
HCO3- + OH- => CO3^-2 + H2O Specify the conjugate pairs and , which direction the reaction equilibrium
3 answers
2,221 views
Determine that which directions ( left or right ) shift , of these following equations according to the Entropy
1) HCl (l) <==>
1 answer
375 views
NH3(g) + H2O(l) <==> NH4+ (aq) + OH- (aq)
a) According to delta H ( Enthalpy ) , which direction the equation will shift ? b)
6 answers
2,968 views
I have trouble how to resist pH in buffer solutions ( in acidic buffer , and in basic buffer ) when we add an acid , and a base
4 answers
557 views
HF + H2O <==> H3O+ + F-
By dissolving 0.03 mol HF in 1 L water , seen that [HF] at the equilibrium is 0.027 M , then : 1) If we
2 answers
516 views
Classify these mixtures to homogeneous and heterogeneous
a) orange juice b) tap water ( home water )
2 answers
1,170 views
Determine the solvent and solute in the following :
a) carat 14 gold b) gaseous drinking ( pepsi for ex.)
4 answers
2,414 views
What indicator is better in the following titrations :
1) strong acid/strong base a) methyl red (4.4 - 6.2 ) b) bromophenol blue
1 answer
481 views
What is difference between equivalence point and end point in the titration ?
2 answers
537 views
How can we determine the equivalence point ( or end point ) in the curves in titration ( strong acid/weak base and weak
2 answers
665 views
How do the indicators work , by changing color ?
1 answer
445 views
What is the molality of 22.5 g acetone
(CH3)2CO , in 200 g water ? ( the answer is 22.0 m , that I think is wrong .. )
5 answers
549 views
Why dissolving gases in the liquids is exothermic while the phase is down ? explain please
4 answers
462 views
The solubility of LiCl is 83.5 g/100 g H2O at 20 oC , and is 89.8 g / 100 g H2O at 40 oC , then what is the required mass (in
3 answers
1,148 views
The solubility of NaNO3 at 40 oC is 102 g/100 g H2O , what is the minimum amount of water to dissolve NaNO3 ( mass of solvent )
3 answers
586 views
Which solute will yield a saturated solution ( in the previous two question ) when we dissolve 36 g of each in 25 g of water at
1 answer
406 views
How can we prepare or change :
1) change unsaturated to saturated soln? 2) change unsaturated to supersaturated? 3) change
1 answer
389 views
Does a molecular compound in water have hydration or have ionization ?
1 answer
312 views
I can't understand rounding rules of numbers
Can you simply explain it ?
1 answer
411 views
If we have :
H2(g) + 1/2 O2(g) -> H2O(l) dHf= -285.5 Kj N2O5(g) + H2O(l) -> 2HNO3 dHf = -76.6 Kj 1/2 N2 + 3/2 O2 + 1/2 H2 -> HNO3
3 answers
1,084 views
Are there any tips to help to learn and memorizing the phrasal verbs in english ?
With Respects
2 answers
559 views
I want to write a CV , could you help and notice me how to do it ?
with respects
1 answer
446 views
A person hammered a 0.5 kg something (substance ) with a hammer that its weight is 2.5 kg , with the velocity 65 m /s ,, if one
2 answers
465 views
A piece of ice its mass is 2.5 kg and at 0.0 C temperature , it is crawling on the ground with 5.7 m/s , what is the mass of the
4 answers
602 views
What is basically difference between the following :
1)Internal energy and latent heat 2)Internal energy and potential energy I'm
1 answer
395 views
N = Sp.gr*1000* percent% / eq.wt
Prepare 200 ml of 5 N H2SO4 solution from concentrated H2SO4 , if we know that Sp.gr = 1.84 g/ml
1 answer
390 views
I have three questions if you please, can I take protein even if with no any workout? can I take amino acid pills in lower dose
1 answer
512 views
Which one of these properties is directly proportional to molality and why?
A) Electrical conductance B) Heat of solution C)
1 answer
368 views
