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Oduvanchick [21]
3 years ago
15

Which of the following ions would represent the ion of an element from group 2A

Chemistry
1 answer:
Oxana [17]3 years ago
3 0
Would you mind listing the options? 
You might be interested in
1 C8H10(l) +21/2O2(g) → 8CO2(g) + 5H2O(g), Hcomb= ? Hf for C8H10(l) = +49.0kJ/mol C8H10(l) Use the balanced combustion reaction
nikklg [1K]

Answer:

H_{comb}=-4406kJ/mol

Explanation:

Hello,

In this case, the enthalpy of combustion is understood as the energy released when one mole of fuel, in this case octene, is burned in the presence of oxygen and is computed with the enthalpies of formation of the fuel, carbon dioxide and water as shown below (oxygen is circumvented as it is a pure element):

H_{comb}=8*\Delta _fH_{CO_2}+5\Delta _fH_{H_2O}-\Delta _fH_{C_8H_{10}}

Thus, since we already know the enthalpy of combustion of the fuel, for carbon and water we have -393.5 and -241.8 kJ/mol respectively, thereby, the enthalpy of combustion turns out:

H_{comb}=8*(-393.5kJ/mol)+5(-241.8kJ/mol)-49.0kJ/mol\\\\H_{comb}=-4406kJ/mol

Best regards.

4 0
3 years ago
A sealed reaction vessel initially contains 1.113×10-2 moles of water vapor and 1.490×10-2 moles of CO(g).
Molodets [167]

Answer:

Kc =\frac{[8.326x10-3]^{1} }{[1.113x10-2]^{1}[1.490x10-2]^{1}  }

Kc = 50.2059

Explanation:

1. Balance the equation

2. Use the Kc formula

Remember that pure substances, like H2 are not included on the Kc formula

4 0
3 years ago
A watt is a unit of power or energy per unit time (1 W = 1 J/s). A semiconductor laser in a CD player has an output wavelength o
GREYUIT [131]

Answer:

n = 2.208x10¹⁸ photons

Explanation:

The energy of a photon( an elementary particle) is given by the equation:

E = nxhxf

Where n is the number of photons, h is plank constant (6,62x10⁻³⁴ J.s), and f is the frequency. Knowing that the power level is 0.120mW (1.2x10⁻⁴ W), the energy in J, for a time of 78 min (4680 s)

E = 1.2x10⁻⁴x4680 = 0.5616 J

The frequency of a photon is its velocity ( c= 3x10⁸ m/s) divided by its wavelength, which is 780 nm = 780x10⁻⁹ m

f = 3x10⁸/780x10⁻⁹

f = 3.846x10¹⁴ s⁻¹

Then, the number of photons is:

0.5616 = nx6,62x10⁻³⁴x3.846x10¹⁴

n = 2.208x10¹⁸ photons.

5 0
3 years ago
19
Luda [366]
Bit.my/3a8Nt8n here’s the link for the answer
3 0
3 years ago
The following is a carbohydrates,lipid,protein or nucleic acid:Wax
Rasek [7]
A wax is a type of lipid. Waxes are nonpolar, so they are not soluble in water.
3 0
3 years ago
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