Newest questions posted by MAD
  1. History

    Hello! I was wondering if anyone could check my answers please. From :WorldWarII posters from the national museum of American history. According to the text the World War II poster was ideal agent for what? A. For promoting sales of bonds and stamps in
  2. Math

    hello! I really need help with this math problem on a portfolio I am doing, I know you're not supposed to give answers out and I'm not asking for any answers but I honestly don't understand this I've watched the profolio recording as well and help from
  3. History

    Hello! I'm going a project on Jim crow laws and I'm having trouble finding people who helped or where an important to it, Anything helps thank you!
  4. Math homework Help Please

    Hii so, I'm on my 5th mental breakdown Today and Its only 9:00 today, and as I know most of you don't care what so ever about what I'm going through and you all have your own problems but I'm honestly horrible at math and this is a big grade for me in it
  5. Chemistry

    Which one of these properties is directly proportional to molality and why? A) Electrical conductance B) Heat of solution C) Equilibrium of solution D) Vapour pressure Thanks
  6. physic mechanic

    All of the following forces are central force, EXCEPT Semua yang berikut adalah daya berpusat KECUALI A)Coulomb force Daya Coulomb B) Frictional force Daya geseran
  7. physic mechanic

    A particle is pushed horizontally by a constant horizontal force of magnitude F, which starts from the rest at x=0 in the positive ݔ direction. During the movement, it is also acted by the air resistance force that equivalent to bv, where b is the
  8. physic

    A particle is pushed horizontally by a constant horizontal force of magnitude F, which starts from the rest at x=0 in the positive ݔ direction. During the movement, it is also acted by the air resistance force that equivalent to bv, where b is the
  9. physic

    All of the following forces are central force, EXCEPT A)Coulomb force B) Frictional force C)Gravitational force D)Electrostatic force
  10. physic

    An ant with mass 0.15 g lands on one end of a floating 4.75 g stick. After sitting at rest for a moment, it runs toward the other end with a speed of 3.8 cm/s relative to the river. What is the speed of the stick if it moves in the opposite direction? A)
  11. physic mechanic

    An ant with mass 0.15 g lands on one end of a floating 4.75 g stick. After sitting at rest for a moment, it runs toward the other end with a speed of 3.8 cm/s relative to the river. What is the speed of the stick if it moves in the opposite direction?
  12. Exercise\workout

    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 to meet some deficiencies ? and, can I take protein along with amino acids for bodybuilding ? Thank you so much
  13. Physics

    A hostess wants to cool her 100g of soup which is currently at 50Celsius, and it's specific heat is 0.8 cal/g celsius, by adding water (specific heat = 1 cal/ g celsius) at a temperature of 5Celsius, how much water should she add, assuming that all the
  14. Chemistry

    N =*1000* percent% / eq.wt Prepare 200 ml of 5 N H2SO4 solution from concentrated H2SO4 , if we know that = 1.84 g/ml , percent = 98% , At.wt for (H= 1 , S=32 , O =16 ) Thank you a lot
  15. physics

    What is basically difference between the following : 1)Internal energy and latent heat 2)Internal energy and potential energy I'm really confused , because they're so close in meaning. Thanks
  16. physics

    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 melted ice , if we know all of the kinetic energy of the ice turn into the internal energy (of the ice ) , that we need 3.3 X
  17. physics

    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 third of the hammer's energy turn into the internal energy to both of the substance and the hammer , then what is the change
  18. science

    I want to write a CV , could you help and notice me how to do it ? with respects
  19. english language

    Are there any tips to help to learn and memorizing the phrasal verbs in english ? With Respects
  20. Chemistry

    What is name of this according to the IUPAC: a benzene that has an ethyl group on an its carbon , and a double methyl group on another carbon ? thanks
  21. chemistry

    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 dHf = - 174.1 Kj then , what is the dHf of 2N2 + 5O2 -> 2N2O5
  22. math

    I can't understand rounding rules of numbers Can you simply explain it ?

    Does a molecular compound in water have hydration or have ionization ?

    How can we prepare or change : 1) change unsaturated to saturated soln? 2) change unsaturated to supersaturated? 3) change saturated to unsaturated ? 4) change saturated to supersaturated ? 5) change supersaturated to unsaturated? 6) change supersaturated

    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 25 oC ? and why ?

    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 ) ?

    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 gram ) of LiCl to obtain a saturated solution in 300 g H2O at 25 oC ? please explain thank a lot

    Why dissolving gases in the liquids is exothermic while the phase is down ? explain please

    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 .. )

    How do the indicators work , by changing color ?

    How can we determine the equivalence point ( or end point ) in the curves in titration ( strong acid/weak base and weak acid/strong base )

    What is difference between equivalence point and end point in the titration ?

    What indicator is better in the following titrations : 1) strong acid/strong base a) methyl red (4.4 - 6.2 ) b) bromophenol blue (6.2 - 7.6 ) 2) strong acid/weak base a) methyl orange (3.1 - 4.4 ) b) bromophenol blue (3.0 - 4.6 ) 3) weak acid/strong a)

    Determine the solvent and solute in the following : a) carat 14 gold b) gaseous drinking ( pepsi for ex.)

    Classify these mixtures to homogeneous and heterogeneous a) orange juice b) tap water ( home water )

    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 divide 0.03 mol/ 1 L it would be 0.03 M , why that difference ? 2) How many moles HF in 1 L water is required to reach the

    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 ! how the reactions in buffer follow Le chatlier's principle ?

    NH3(g) + H2O(l) NH4+ (aq) + OH- (aq) a) According to delta H ( Enthalpy ) , which direction the equation will shift ? b) According to Entropy , which direction the equation will shift ? c) Assuming that delta G is positive , then delta S is greater than

    Determine that which directions ( left or right ) shift , of these following equations according to the Entropy 1) HCl (l) HCl (g) 2) C6H12O6 (aq) C6H12O6 (s) 3) 2NH3 (g) N2(g) + 3H2(g) 4) 3C2h$(g) C6H12 (l)

    If heat of combustion of acetylene C2H2 is -1301.1 kJ/mol then : a) Write balanced thermochemical equation of acetylene combustion b) If 0.25 mol C2H2 reacted according to the previous equation , and what is the emitted energy ? c) how many grams needed to

    We have this reaction : HCO3- + OH- => CO3^-2 + H2O Specify the conjugate pairs and , which direction the reaction equilibrium shift ? and How ( as a rule ) ?

    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 of them is acid ? And is that also bronshted- lowry acid ? explain thanks

    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) 0.5 m glucose 4) 0.2 m sucrose and why ?

    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 , what is the amount of KClO3 that can be dissolved ? is the solution unsaturated , saturated , or super saturated ? thank you

    Dye of iodine is prepared by dissolving in ethanol , and 1% ( one percent ) of this solution contains 10 g of solute in 1000 g of solution 1) how many grams of solvent is there in the solution ? 2) how many moles of solute ( I2) is there? 3) what is the

    Is these two electrodes appropriate to create a good battery ? : Cd => Cd^+2 + 2e- and Fe => Fe^+2 + 2e- Explain

    If a nickel rod embedded in a silver nitrate solution , what do we predict ? explain

    Assuming that this half cell I2 + 2e- + =>2I- as standard electrode and assumed its potential that is 0.00 V : a) what is standard potential of this half cell : Br2 + 2e- + => 2Br- b) what is standard potential of this half cell : Al^+3 + 3e- => Al

    Can a substance made of zinc be coated by nickel , using nickel nitrate solution ? How ?

    In electrolysis , which reaction does occur on the cathode , half oxidation reaction or reduction ?

    Why can't we use water in electrolytic cell during producing aluminium ?

    Why does hydrogen electrode have 0.00 V ? or assumed that has 0.00 V ?

    why dry cells are called dry while they contain water ? in electrochemistry

    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 we know that reduction potential of Sn is Sn^+2 + 2e- Sn : -0.14 V

    What is the function ( or role ) of platinum in electrochemistry in general ? I read a question about platinum in electric potential , and in standard electrode potential ?! thank you a lot

    How many oxidation states Should a substance have at least to undergo Disproportionation reaction ? thanks

    A substance contains an element at its probable maximum oxidation number , does this substance have a maximum chance to be an oxidizing agent or have a minimum chance to be a reducing agent ? thank you

    I have trouble finding out the oxidation number of each element in the : [Cr(N2h4CO)6]4[Cr(CN)6]3

    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) KMnO4 + KIO3 => MnO2 + KIO4 ( in a basic solution ) 2) MnO4- + Cl- => Mn^+2 + HClO ( in a acidic solution ) I think these are

    Balance the oxidation reduction equation in half reaction PbO2 + KCl => KClO + KPb(OH)3 thank you a lot

    Why the oxidation number of ( H ) is -1 in 1) N2H4 2) CaH2 while ( N ) is different from ( Ca ) ?

    In half reaction method of the chemical equation balancing , how about those redox reactions that they don't contain any (H) and ( O ) atoms ?

    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) Is F2 reduced by Cl- 5) Is Br2 reduced by Cl- and if you or no , how it is as a rule to predict any ? thank you

    Assume that the ( S ) ( S ; alphabet ) is the solubility in mol/L of AB2 compound , , then what is the concentration of A and B ? and what is the Ksp of AB2 compound ? thank you a lot

    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 (hydroxyapatite) reacts with fluoride , then the F- ions replace OH- ions and the product is Ca5(PO4)3F ,, if we know the Ksp of (

    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

    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

    Which conditions ( reactant concentration , pressure , and temperature ) elevate high concentration of the underlines in these following equilibrium systems : 1) 2CO + O2 2CO2 + 167 kJ 2) Cu^+2 + 4NH3 [ Cu(NH3)4 ]^+2 + 24 kJ 3) 2HI + 12.6 kJ H2 + I2 4)

    We have this following gas equilibrium : H2 + Cl2 2HCl + 184 kJ then predict the following to know Le chatlier's prediction 1) adding Cl2 2) removing HCl 3) elevation of pressure 4) lowering of the temperature 5) removing H2 and lowering pressure 6) adding

    The enthalpy change of an endothermic reaction is 8 kJ , and this reaction is spontaneous at 25 oC ,, what is the expected entropy change ? thank you a lot

    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 so much

    Which of the following is the conjugate acid to a base in these options : 1) PO4^-3 2) H2O 3) H3PO4 4) H2PO4^-

    Which of the following is the conjugate acid to a base in these options : 1) PO4^-3 2) H2O 3) H3PO4 4) H2PO4^-

    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

    A) We have an experiment , using the solution of KNO3 , measured freezing point of solution is -1.15 degree , and using a sample of pure water the thermometer read o.25 degree as freezing point of the sample , calculate the molal concentration of KNO3

    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 of the substance can be crystallized in a saturated solution that contain 200 g of water , if the solution cooled from 60 to 20
  77. Chem

    given the reaction: agcl(s) +2nh3 (aq) ag (nh3)2 +(aq) + cl^- (aq). if more ammonia, nh3 is added to the system at equilibrium the a) amount of agcl increases b) system cannot achieve equilibrium c) rate of the forward reaction decreases d) concentration
  78. Chem

    consider the equilibrium reaction: pbcro4(s) pb^2+ (aq) +cro4^2- (aq). A saturated solution of lead chromate, pbcro4 has a lead ion concentration of 1.4 x 10^-7 m. what is the value of the solubility product ksp for lead chromate?
  79. math

    The volume V of a pyramid varies jointly as the area of the 1. ________________________ base B and the height h, and V=24 ft3 when B=12 ft2 and h=6ft. Find B when V=54 ft3 and h=9 ft.
  80. Chemistry

    what is the molality of a solution prepared by dissolving 13.0 g of Ba(NO3)2 in 450 g of water?
  81. maths

    p-mv2\r=mg make m the subject