Answer:
The correct option is;
c. The scientist can make and record observations
Explanation:
Empirical evidence are evidences obtained by direct observation, sensual perception or direct measurement. It is the processed and useful data gathered and stored in a material form or documented to provide record of the measurement.
With the aid of empirical evidence, it is possible for researchers to find answers to question regarding topics that can vastly impact every day life.
With empirical evidence, it is possible to determine the effects of treatment in a study such as the invention of working car safety devices such as seat belts and airbags.
Answer: If the potential energy of the reaction system decreases, then kinetic energy in the surroundings increases and the temperature of the surroundings rises
Explanation:
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
Given the number of a substance, we can solve the number of moles by using a conversion factor that would relate the number of a substance to the number of moles. In any case, Avogadro's number would be used. It <span>represents the number of
units in one mole of any substance. This has the value of 6.022 x 10^23 units /
mole. This number can be used to convert the number of atoms or molecules into
number of moles. For example, we are given 1.23 x 10^24 atoms of a substance converting it to moles we do as follows:
</span>1.23 x 10^24 atoms ( 1 mol / 6.022x10^23 atoms ) = 2.04 moles
