Answer:
ΔS > 0 only for choice E: CH4(g) + H2O (g) → CO(g) + 3 H2(g)
Explanation:
Our strategy in this question is to use the trend in entropies :
S (solids) less than S (liquids) less than S (gases)
Also we have to look for the molar quanties involved of each state and their change to answer the question:
A. N2(g) + 3 H2(g) → 2 NH3(g)
Here we have 4 moles gases going to 2 moles of products, so the change in entropy is negative.
B. Na2CO3(s) + H2O(g) + CO2(g) → 2 NaHCO3(s)
The change in entropy is negative since we have 2 mol gases in the reactants and zero in the products.
C. CH3OH(l) → CH3OH(s)
A liquid has a higher entropy than a solid so ΔS is negative
D. False see A,B,C
E. The change in moles of gases is 4 - 2= 2, therefore ΔS is greater than O.
Water is a very good solvent due to its very polar nature. A polar substance is one where the atoms within the molecules of the substance carry partial charges. Oxygen is very electronegative, so it induces partial charges within the bonds of the water molecule. The extremely polar nature of water, along with its ability to make hydrogen bonds, ensure that it is able to dissolve a variety of substances.
The mass of Ca(CN)2 : 92,11 g/mol
<h3>Further explanation</h3>
Given
0.0321 moles of Ca(CN)2
Required
The mass
Solution
The mole is the number of particles contained in a substance
1 mol = 6.02.10²³
Moles can also be determined from the amount of substance mass and its molar mass
mol(n) = mass(m) : MW(molecular weight)
Input the value :
mass = mol x MW Ca (CN)2
mass = 0.0321 x 92,11 g/mol
mass = 2.957 g
Answer:
The addition of sulfate ions shifts equilibrium to the left.
Explanation:
Hello!
In this case, according to the following ionization of strontium sulfate:
It is evidenced that when sodium sulfate is added, sulfate, is actually added in to the solution, which causes the equilibrium to shift leftwards according to the Le Ch athelier's principle. Thus, the answer in this case would be:
The addition of sulfate ions shifts equilibrium to the left.
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Based on the trend of electronegativities values of the elements <em>Be, Mg, Ca, </em>and,<em> Sr</em> within their group (increasing from bottom to top), the atoms of the element Sr will have the <u>least attraction</u> for an electron.
We need to remember that electronegativity indicates the affinity or attraction of an element for an electron. Hence, the <u>higher</u> the <em>electronegativity,</em> the<u> higher</u> the <em>attraction </em>of that element for an <em>electron</em>.
The values of <em>electronegativities </em>of the given <em>elements </em>are the following:
Be = 1.57
Mg = 1.31
Ca = 1.0
Sr = 0.95
We can see that the increasing trend of <em>electronegativities </em>in this group is from the <u>bottom to the top</u>, having the Sr with the lowest electronegativity value and the <em>Be</em> with the <em>highest</em>.
This trend is related to atomic size, the <u>larger</u> the <em>atomic size</em>, the <u>lower</u> the <em>electronegativity</em> because the <em>electron </em>in the outermost shell will feel <u>less attraction</u> towards the nucleus of an atom. In a group of the periodic table, the <em>size </em>of an <em>atom </em>will <em>increase </em>from <u>top to bottom</u>.
Therefore, according to the said above, the atoms of the Sr will have the least attraction for an electron (it has the lower electronegativity value).
Find more about electronegativity here:
I hope it helps you!