Answer:
5.85 grams of NaCl should be added to 250 grams of water to make a 0.40 m solution.
Explanation:
Mass of NaCl =x
Molar mass of NaCl = 58.5 g/mol
Molality of the solution = 0.40 m
Mass of the solvent = 250 g = 0.250 kg (1g = 0.001 kg)
5.85 grams of NaCl should be added to 250 grams of water to make a 0.40 m solution.
First, assume the order of the given reaction is n, then the rate of reaction i.e. ![\frac{dx}{dt}=k\times[A]^{n}](https://tex.z-dn.net/?f=%5Cfrac%7Bdx%7D%7Bdt%7D%3Dk%5Ctimes%5BA%5D%5E%7Bn%7D)
where, dx is change in concentration of A in small time interval dt and k is rate constant.
According to units of rate constant, the reaction is of second order.
![\frac{1}{[A]_{t}}-\frac{1}{[A]_{o}} = kt](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B%5BA%5D_%7Bt%7D%7D-%5Cfrac%7B1%7D%7B%5BA%5D_%7Bo%7D%7D%20%3D%20kt)
(second order formula)
Put the values,
t= 587.9 s
Hence, time taken is 587.9 s
Explanation:
Molar mass
The mass present in one mole of a specific species .
The molar mass of a compound , can easily be calculated as the sum of the all the individual atom multiplied by the number of total atoms .
(a) P₄
Molar mass of of the atoms are -
Phosphorous , P = 31 g/mol
Molecular mass of P₄ = ( 4 * 31 ) = 124 g/mol .
(b) H₂O
Molar mass of of the atoms are -
Hydrogen , H = 1 g/mol
oxygen , O = 16 g/mol.
Molecular mass of H₂O = ( 2 * 1 ) + ( 1 * 16 ) = 18 g/mol
(c) Ca(NO₃)₂
Molar mass of of the atoms are -
calcium , Ca = 40 g/mol
nitrogen, N = 14 g/mol
oxygen , O = 16 g/mol.
Molecular mass of Ca(NO₃)₂ = ( 1 * 40 ) + ( 2 * 14 ) + ( 6 * 16 ) = 164 g/mol.
(d)CH₃CO₂H (acetic acid)
Molar mass of of the atoms are -
Carbon , C = 12 g/mol.
oxygen , O = 16 g/mol.
Hydrogen , H = 1 g/mol
Molecular mass of CH₃CO₂H =( 2 * 12 ) + (2 * 16 ) + (4 * 1 ) = 60 g/mol.
(e) C₁₂H₂₂O₁₁ (sucrose, cane sugar).
Molar mass of of the atoms are -
Carbon , C = 12 g/mol.
oxygen , O = 16 g/mol.
Hydrogen , H = 1 g/mol
Molecular mass of C₁₂H₂₂O₁₁ = (12 * 12 ) + ( 22 * 1 ) + ( 11 * 16 ) = 342 g/mol.
Electrolytes are substances which are capable of producing a solution that has the ability to conduct electricity. These electrolytes are formed from the dissociation of salts into ions. The positive ions are named cations while the negative ions are termed anions.
Hence, the answer to these item is SALT. Salt are substances produced by the reaction of cations and anions.
