Answer:
Percentage yield = 85.2%
Explanation:
Given data:
Mass of Mg = 21.3 g
Actual yield of MgO = 30.2 g
Percentage yield = ?
Solution:
Chemical equation:
2Mg + O₂ → 2MgO
Number of moles of Mg = mass/molar mass
Number of moles of Mg = 21.3 g / 24.3 g/mol
Number of moles of Mg = 0.88 mol
Now we will compare the moles of MgO with Mg.
Mg : MgO
2 : 2
0.88 : 0.88
Mass of MgO:
Mass of MgO= moles × molar mass
Mass of MgO= 0.88 mol × 40.3g/mol
Mass of MgO = 35.46 g
Actual yield of MgO = 30.2 g
Percentage yield:
Percentage yield = Actual yield/theoretical yield × 100
Percentage yield = 30.2 g/ 35.46 g × 100
Percentage yield = 85.2%
The answer to 4 is A.
The answer to 5 is C.
Answer:
20703.6J
Explanation:
Quantity of heat (Q) = mass of dioxane × enthalpy of fusion
Mass of dioxane = 142g
Enthalpy of fusion of dioxane = 145.8J/g
Q = 142g × 145.8J/g = 20703.6J
Answer:
Q3. A bridge is built without expansion gaps.
Explain what could happen to the bridge if the temperature became:
a) much hotter than the day it was built.
b) much colder than the day it was built.
P.s. (this is not a select option question, explain each according to the question)
I would i have think it is either a) east or c) west b/c couldn’t go by it self
