Hi there! I was looking at this a few days ago for school and found this
Answer:
ΔH°r = -1562 kJ
Explanation:
Let's consider the following combustion.
C₂H₆(g) + 7/2 O₂(g) ⇒ 2 CO₂(g) + 3 H₂O(l)
We can calculate the standard heat of reaction (ΔH°r) using the following expression:
ΔH°r = ∑np × ΔH°f(p) - ∑nr × ΔH°f(r)
where,
ni are the moles of reactants and products
ΔH°f(i) are the standard heats of formation of reactants and products
The standard heat of formation of simple substances in their most stable state is zero. That means that ΔH°f(O₂(g)) = 0
ΔH°r = ∑np × ΔH°f(p) - ∑nr × ΔH°f(r)
ΔH°r = [2 mol × ΔH°f(CO₂) + 3 mol × ΔH°f(H₂O)] - [1 mol × ΔH°f(C₂H₆) + 7/2 mol × ΔH°f(O₂)]
ΔH°r = [2 mol × (-394.0 kJ/mol) + 3 mol × (-286.0 kJ/mol)] - [1 mol × (-84.00 kJ/mol) + 7/2 mol × 0]
ΔH°r = -1562 kJ
Answer:
A.
Explanation:
An equation with the equal amount and proportion of atoms of each element on both sides of the reaction is commonly referred to as a balanced chemical equation.
The law of conservation of matter asserts that no observable and empirical change in the amount of matter occurs within a conventional chemical process. As a result, each element in the product would have the same equal amount or numbers of atoms as the reactants.
Answer : The density of an object is 0.93 g/mL
Explanation : Given,
Mass of an object = 3.8 g
Initial volume = 4.5 mL
Final volume = 8.6 mL
First we have to calculate the volume of an object.
Volume of an object = Final volume - Initial volume
Volume of an object = 8.6 mL - 4.5 mL
Volume of an object = 4.1 mL
Now we have to calculate the density of an object.
Formula used:

Now putting all the given values in this formula, we get:


Therefore, the density of an object is 0.93 g/mL
Answer:
There is an extra O2 molecule left over
Explanation: