Based on the balanced chemical reaction presented above, every mole of magnesium (Mg) yields one mole of diatomic hydrogen (H2). When converted to masses, every 24.3 grams of magnesium yields 2 grams of hydrogen.
From the given, there are 20 grams of magnesium available for the reaction. With this amount, the expected yield of hydrogen is 1.646 grams. To calculate the percent yield, divide the actual yield to the hypothetical yield.
*The case is impossible because the actual yield is greater than the theoretical yield.
If we assume that there had been a typographical error and that the actual yield is 0.7 grams instead of 1.7 grams, the percent yield becomes 42.5%. Thus, the answer is letter E.
The more finely divided the solid is, the faster the reaction happens. A powdered solid increases the rate of the reaction than the same mass present as a single lump. The powdered solid has greater surface are than the single lump.
Answer:
C₇H₁₄O₂
Explanation:
From the question given above, the following data were obtained:
Mass of compound = 1.152 g
Mass of CO₂ = 2.726 g
Mass of H₂O = 1.116 g
Empirical formula =?
Next, we shall determine the mass of carbon, hydrogen and oxygen present in the compound. This can be obtained as follow:
For carbon (C):
Mass of CO₂ = 2.726 g
Molar mass of CO₂ = 12 + (2×16)
= 12 + 32
= 44 g/mol
Mass of C = 12/44 × 2.726
Mass of C = 0.743 g
For hydrogen (H):
Mass of H₂O = 1.116 g
Molar mass of H₂O = (2×1) + 16
= 2 + 16
= 18 g/mol
Mass of H = 2/18 × 1.116
Mass of H = 0.124 g
For oxygen (O):
Mass of compound = 1.152 g
Mass of C = 0.743 g
Mass of H = 0.124 g
Mass of O =?
Mass of O = (Mass of compound) – (Mass of C) + (Mass of H)
Mass of O = 1.152 – (0.743 + 0.124)
Mass of O = 1.152 – 0.867
Mass of O = 0.285 g
Finally, we shall determine the empirical formula for the compound as follow:
C = 0.743 g
H = 0.124 g
O = 0.285 g
Divide by their molar mass
C = 0.743 / 12 = 0.062
H = 0.124 / 1 = 0.124
O = 0.285 / 16 = 0.018
Divide by the smallest
C = 0.062 / 0.018 = 3.44
H = 0.124 / 0.018 = 7
O = 0.018 / 0.018 = 1
Multiply by 2 to express in whole number.
C = 3.44 × 2 = 7
H = 7 × 2 = 14
O = 1 × 2 = 2
Empirical formula => C₇H₁₄O₂