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3 years ago

Which statement describes the Arrhenius interpretation of acids and bases?

1 answer:

6 0

Answer: Composition is an orderly arrangement of visual structures (elements and principles) to create a mood, add meaning and direct the viewers' attention to the purpose of the artwork. Compositions are said to be 'designed' according to the specific intent of the artist.

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What is the maximum number of electrons that can be contained in the first, second, third, and fourth energy levels, respectivel

Natalija [7]

It can be determined by 2n^2 formula
where "n" is the no of shell:
1st shell = 2n^2 = 2(1)^2 = 2*1 = 2 electrons
2nd shell = 2n^2 = 2(2)^2 = 2*4 = 8 electrons
3rd shell = 2n^2 = 2(3)^2 = 2*9 = 18 electrons
4th shell = 2n^2 = 2(4)^2 = 2*16 = 32 electrons.

6 0

3 years ago

(a) How much negative charge is on each oxygen of the carbonate ion?

Eva8 [605]

The chemical formula of a carbonate ion is CO3^2-. It is an AX3 system which means it take the trigonal planar shape. There would be two single bonds of C-O and one double bond C-O in order for C to agree with the octet rule. Two minus charges are equally distributed to the three oxygen atoms so that each oxygen of the carbonate ion would have a charge of negative 2/3.

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3 years ago

What is the correct notation for a calcium ion whose outershell is a full octet?

horsena [70]

Ca^(2+). Calcium is an alkaline earth metal with an atomic number of 20. Its electronic configuration is (2, 8, 8, 2). From the electronic configuration it would be observed that calcium has two valence electrons. Calcium shares these two electrons with non metals like sulphur in an ionic bond to obtain an outer shell which is full octet. Let me use Sulphur. When calcium gives out its two valence electrons its electronic configuration becomes (2, 8, 8) thereby obtaining a stable out shell and the calcium ion becomes Ca^(2+). The sulphur also obtains a stable octet because it has 6 valence electron initially.

8 0

3 years ago

Write a balanced equation for the combustion of C7H16(l) (heptane) -- i.e. its reaction with O2(g) forming the products CO2(g) a

JulsSmile [24]

Answer:

The standard enthalpy of reaction = -4854.7kJ

The difference: ΔH-ΔE = Δ(PV) = Δn.R.T = 9910.288 J ≈ 9.91 kJ

Explanation:

The balanced chemical equation for the combustion of heptane:

C₇H₁₆ (l) + 11 O₂ (g) → 7 CO₂ (g) + 8 H₂O (l)

Given: The standard enthalpy of formation ( $\Delta H _{f}^{\circ }$ ) for: C₇H₁₆ (l) = -187.8 kJ/mol, O₂ (g) = 0 kJ/mol, CO₂ (g) = -393.5 kJ/mol, H₂O (l) = -286 kJ/mol

To calculate the standard enthalpy of reaction ( $\Delta H _{r}^{\circ }$ ) can be calculated by the Hess's law:

$\Delta H _{r}^{\circ } = \left [\sum \nu \cdot\Delta H _{f}^{\circ }(products) \right ] - \left [\sum \nu\cdot\Delta H _{f}^{\circ }(reactants) \right ]$

Here, $\nu$ is the stoichiometric coefficient

⇒ $\Delta H _{r}^{\circ } =$

$\left [ 7\times \Delta H _{f}^{\circ }\left (CO_{2}\right )+ 8\times \Delta H _{f}^{\circ }\left (H_{2}O \right )\right ]$

$- \left [1\times \Delta H _{f}^{\circ }\left (C_{7}H_{16}\right ) +11\times \Delta H _{f}^{\circ }\left (O_{2} \right ) \right ]$

$=\left [ 7\times \left (-393.5 kJ/mol \right )+ 8\times \left (-286 kJ/mol \right )\right ]$

$-\left [1\times \left (-187.8 kJ/mol \right ) +11\times \left (0 kJ/mol \right ) \right ]$

⇒ $\Delta H _{r}^{\circ } = \left [ \left (-2754.5 \right )+ \left (-2288 \right )\right ]\left -[ \left (-187.8 \right ) +\left (0 \right )\right ]$

⇒ $\Delta H _{r}^{\circ } = \left [ -5042.5 ]\left -[ -187.8] = \left ( -4854.7kJ \right )$

To calculate the difference: ΔH-ΔE=Δ(PV)

We use the ideal gas equation: P.V = n.R.T

⇒ ΔH-ΔE=Δ(PV) = Δn.R.T

Given: Temperature:T = 298K, R = 8.314 J⋅K⁻¹⋅mol⁻¹

Δn = number of moles of gaseous products - number of moles of gaseous reactants = (7)- (11) = (-4)

⇒ ΔH-ΔE=Δ(PV) = Δn.R.T = (-4 mol) × (8.314 J⋅K⁻¹⋅mol⁻¹) × (298K) = 9910.288 J = 9.91 kJ (∵ 1 kJ = 1000J )

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3 years ago

How does the motion of the particles change when thermal energy added

Sonbull [250]

The particles move faster when more thermal energy is added creating heat.

6 0

3 years ago

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