Answer:
ΔrxnH = -580.5 kJ
Explanation:
To solve this question we are going to help ourselves with Hess´s law.
Basically the strategy here is to work in an algebraic way with the three first reactions so as to reprduce the desired equation when we add them together, paying particular attention to place the reactants and products in the order that they are in the desired equation.
Notice that in the 3rd reaction we have 2 mol Na₂O (s) which is a reactant but with a coefficient of one, so we will multiply this equation by 1/2-
The 2nd equation has Na₂SO₄ as a reactant and it is a product in our required equation, therefore we will reverse the 2nd . Note the coefficient is 1 so we do not need to multiply.
This leads to the first equation and since we need to cancel 2 NaOH, we will nedd to multiply by 2 the first one.
Taking 1/2 eq 3 + (-) eq 2 + 2 eq 1 should do it.
Na₂O (s) + H₂ (g) ⇒ 2 Na (s) + H₂O(l) ΔrxnHº = 259 / 2 kJ 1/2 eq3
+ 2NaOH(s) + SO₃(g) ⇒ Na₂SO₄ (s) + H₂O (l) ΔrxnHº = -418 kJ - eq 2
+ 2Na (s) + 2 H₂O (l) ⇒ 2 NaOH (s) + H₂ (g) ΔrxnHº = -146 x 2 2 eq 1
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Na₂O (s) + SO₃ (g) ⇒ Na₂SO₄ (s) ΔrxnHº = 259/2 + (-418) + (-146) x 2 kJ
ΔrxnH = -580.5 kJ
B. We are in the cenzoic era so what previously had happen to cause the life we live today was a huge mass extinction.... hope this helps!!
The correct answers are ,
A) C
B) N
C) Ti
D) Zn
E) Fe
F) Phosphorus
G)Calcium
H) Helium
I) Lead
J) Silver
<h3>How are elements named?</h3>
Elements have been given names based on a variety of factors, <u>including their characteristics</u>, the compound or ore from which they were extracted, the method by which they were found or acquired, mythical characters, locations, and well-known individuals. Some components have <u>names that are descriptive and are based on one of their attributes.</u>
The International Union of Pure and Applied Chemistry chooses the official element names and symbols (IUPAC). However, different nations frequently use similar names and symbols for elements. Official names and symbols for elements are not given until after their discovery has been confirmed. The discoverer may then suggest a name and a symbol.
There are name standards for several element groupings. Names of halogens end in -ine. All noble gas names, save helium, end in -on. The names of most other elements finish with -ium.
To learn more about elements:
brainly.com/question/14347616
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Physical properties are those which can be observed without any change in composition of the substance. Hence, a is the answer.
