Answer:
friend according to the question the answer is +3 ....
Answer:
0.109 g.
Explanation:
Equation of the reaction:
Na3PO4 + 3HCl --> 3NaCl + H3PO4
Number of moles of HCl = molar concentration × volume
= 0.1 × 0.04
= 0.004 mol.
By stoichiometry, 1 mole of Na3PO4 neutralises 3 moles of HCl. Therefore, number of moles of Na3PO4 = 0.004/3
= 0.0013 mol
Mass of Na3PO4 = molar mass × number of moles
= 0.0013 × 164
= 0.219 g
Since 50% of Na3PO4 was present in the sample. Let 100 g be the total mass of the substance
= 0.219 × 50 g/100 g
= 0.109 g.
Answer:
600 mL
Explanation:
The volume of 10% acid solution used to make the mixture = 200 L
Let the volume of 30% acid solution used to make the mixture = x mL
Total volume of the mixture = (200+ x) mL
For 10% acid solution:
C₁ = 10% , V₁ = 200 mL
For 30% acid solution :
C₂ = 30% , V₂ = x mL
For the resultant solution of sulfuric acid:
C₃ = 25% , V₃ = (200 + x) mL
Using
C₁V₁ + C₂V₂ = C₃V₃
10×200 + 30×x = 25×(200 + x)
Solving for x,
x = 600 mL
<u>600 milliliters of solution Y must be added to 200 milliliters of solution X to create a solution that is 25 percent alcohol by volume.</u>
Answer:
freezing point deceases due to freezing point depression
Answer:
E = 1.8 x 10⁵ J/mol
Explanation:
We are being asked the enery per mol for an emission line corresponding to 649 nm.
The energy of a photon is given by the porduct of Planck's contant times the frequency of the radiation,
E = hν
We also know that the frequency is given by
ν = c/λ
where c is the speed of light (3 x 10 ^8 m/s) and λ is 649 nm given in the problem. Therefore the energy per photon will be given by
E= hc/λ = 6.626 x 10⁻³⁴Js x 3 x 10 ^8 m/s/ 649 x 10 ⁻⁹ m
E = 3.1 x 10 ⁻¹⁹ J/ photon
(Note the wavelength has to be in nanometers (1nm= 10⁻⁹ m) and that the energy we get is the energy per a single photon. Thus we will need to multiply this result by Avogadro's number to answer this question.
E = 3.1 x 10 ⁻¹⁹ J/ photon x 6.022 x 10 ²³photon/mol
E = 1.8 x 10⁵ J/mol