Answer:
1219.5 kj/mol
Explanation:
To reach this result, you must use the formula:
ΔHºrxn = Σn * (BE reactant) - Σn * (BE product)
ΔHºrxn = [1 * (BE C = C) + 2 * (BE C-H) + 5/2 * (BE O = O)] - [4 * (BE C = O) + 2 * (BE O-H).
The BE values are:
BE C = C: 839 kj / mol
BE C-H: 413 Kj / mol
BE O = O: 495 kj / mol
BE C = O = 799 Kj / mol
BE O-H = 463 kj / mol
Now you must replace the values in the above equation, the result of which will be:
ΔHºrxn = [1 * 839 + 2 * (413) + 5/2 * (495)] - [4 * (799) + 2 * (463) = 1219.5 kj/mol
The question is incomplete, the complete question is;
The table above summarizes data given to a student to evaluate the type of change that took place when substance X was mixed with water. The student claimed that the data did not provide enough evidence to determine whether a chemical or physical change took place and that additional tests were needed. Which of the following identifies the best way to gather evidence to support the type of change that occurred when water and Xwere mixed?
A. Measuring the melting point of the mixture of water and X
B. Adding another substance to the mixture of water and X to see whether a solid forms
C Measuring and comparing the masses of the water, X, and the mixture of water and X
D Measuring the electrical conductivities of X and the mixture of water and X
Answer:
D Measuring the electrical conductivities of X and the mixture of water and X
Explanation:
Unfortunately, I am unable to reproduce the table here. However, from the table, the temperature of the of the mixture of the solid X and water was 101.6°C. This is above the boiling point of water and way below the temperature of the solid X.
This goes a long way to suggest that there was some kind of interaction between the water and X which accounted for the observed temperature of the system of X in water.
The only way we can be able to confirm if X actually dissolved in water is to measure the conductivity of the water. dissolved solids increase the conductivity of water.
The formula to be used for this problem is as follows:
E = hc/λ, where h is the Planck's constant, c is the speed of light and λ is the wavelength. Also 1 aJ = 10⁻¹⁸ J
0.696×10⁻¹⁸ = (6.62607004×10⁻³⁴ m²·kg/s)(3×10⁸ m/s)/λ
Solving for λ,
λ = 2.656×10⁻⁷ m or <em>0.022656 nm</em>
Cu has two possible charges: plus 1 and plus 2. Thus, when copper is combined with an anion (negatively charged ion), the anion carries a subscript of one or two. This is shown in the given, Moreover, the given shows copper carries a subscript only of one. This means the anion has an original charge of negative one. These elements belong to the halogen family (Group 17).
<u>Answer:</u> The element represented by M is Strontium.
<u>Explanation:</u>
Let us consider the molar mass of metal be 'x'.
The molar mass of MO will be = Molar mass of oxygen + Molar mass of metal = (16 + x)g/mol
It is given in the question that 15.44% of oxygen is present in metal oxide. So, the equation becomes:
The metal atom having molar mass as 87.62/mol is Strontium.
Hence, the element represented by M is Strontium.
