The reaction is:
C₂H₄ + 3O₂ → 2CO₂ + 2H₂O; ΔH = 1410 kJ
When we reverse this reaction, the sign of the enthalpy change, ΔH, will be changed. The enthalpy change for the reversed reaction would be 1,410 kJ.
Next, we must also multiply the reaction by 2, so the final enthalpy change for the reverse reaction will be:
ΔH = 2,820 kJ
Answer: please make the question more understandable
Explanation:
The amount of the solute is constant during dilution. So the mole number of HCl is 2*1.5=3 mole. The volume of HCl stock is 3/12=0.25 L. So using 0.25 L stock solution and dilute to 2.0 L.
Answer:
khi sôi nhiệt độ của nước đạt 100oC, đến lúc này một phần nước sôi sẽ biến thành hơi nước, hơi nước sẽ đùn lên phá vỡ mặt nước và bốc hơi vào không khí, hình thành lên hiện tượng sôi của nước. Nước sôi đánh dấu mốc chuyển đổi trạng thái từ nước (thể lỏng) sang hơi nước (thể khí).
Explanation:
Unfortunately the data provided doesn't include the DENSITY of the ammonium chloride solution and molarity is defined as moles per volume. So without the density, the calculation of the molarity is impossible. But fortunately, there are tables available that do provide the required density and for a 20% solution by weight, the density of the solution is 1.057 g/ml.
So 1 liter of solution will mass 1057 grams and the mass of ammonium chloride will be 0.2 * 1057 g = 211.4 g. The number of moles will then be 211.4 g / 53.5 g/mol = 3.951401869 mol. Rounding to 3 significant digits gives a molarity of 3.95.
Now assuming that your teacher wants you to assume that the solution masses 1.00 g/ml, then the mass of ammonium chloride will only be 200g, and that is only (200/53.5) = 3.74 moles.
So in conclusion, the expected answer is 3.74 M, although the correct answer using missing information is 3.95 M.
