How many atoms are accommodated by the available orbitals for Ne?

Rewrite the function from vertex form to standard form. Then use either form to calculate f(1) and f(-1).

jonny [76]

Answer:

Standard form: (x+3)^2=1/2(y+3)

f(1) = 29

f(-1) = 5

Explanation:

The standard form of a parabola with a directrix that is horizontal is

(x-h)=4(P)(y-k)

Using the vertex form, find the vertex, foci, and the distance from the vertex to the focus or directrix.

It's easier to use the vertex form to plug in values for x.

f(1) = 2((1)+3)^2-3

f(1) = 29

f(-1) = 2((-1)+3)^2-3

f(-1) = 5

6 0

3 years ago

Which equation correctly relates the heat of reaction to the standard heats of formation?

VARVARA [1.3K]

Answer:

D

Explanation:

∆H° = ∆Hf ° (products) – ∆Hf ° (reactants)

4 0

3 years ago

Consider the following reaction where Kc = 1.80×10-2 at 698 K:

Klio2033 [76]

Answer:

The system is not in equilibrium and the reaction must run in the forward direction to reach equilibrium.

Explanation:

The reaction quotient Qc is a measure of the relative amount of products and reagents present in a reaction at any given time, which is calculated in a reaction that may not yet have reached equilibrium.

For the reversible reaction aA + bB⇔ cC + dD, where a, b, c and d are the stoichiometric coefficients of the balanced equation, Qc is calculated by:

$Qc=\frac{[C]^{c}*[D]^{d} } {[A]^{a}*[B]^{b}}$

In this case:

$Qc=\frac{[H_{2} ]*[I_{2} ] } {[HI]^{2}}$

Since molarity is the concentration of a solution expressed in the number of moles dissolved per liter of solution, you have:

$[H_{2} ]=\frac{2.09*10^{-2} moles}{1 Liter}$ =2.09*10⁻² $\frac{moles}{liter}$

$[I_{2} ]=\frac{4.14*10^{-2} moles}{1 Liter}$ =4.14*10⁻² $\frac{moles}{liter}$

$[I_{2} ]=\frac{0.280 moles}{1 Liter}$ = 0.280 $\frac{moles}{liter}$

So,

$Qc=\frac{2.09*10^{-2} *4.14*10^{-2} } {0.280^{2} }$

Qc= 0.011

Comparing Qc with Kc allows to find out the status and evolution of the system:

If the reaction quotient is equal to the equilibrium constant, Qc = Kc, the system has reached chemical equilibrium.

If the reaction quotient is greater than the equilibrium constant, Qc> Kc, the system is not in equilibrium. In this case the direct reaction predominates and there will be more product present than what is obtained at equilibrium. Therefore, this product is used to promote the reverse reaction and reach equilibrium. The system will then evolve to the left to increase the reagent concentration.

If the reaction quotient is less than the equilibrium constant, Qc <Kc, the system is not in equilibrium. The concentration of the reagents is higher than it would be at equilibrium, so the direct reaction predominates. Thus, the system will evolve to the right to increase the concentration of products.

Being Qc=0.011 and Kc=1.80⁻²=0.018, then Qc<Kc. <u><em>The system is not in equilibrium and the reaction must run in the forward direction to reach equilibrium.</em></u>

8 0

3 years ago

An isotope of potassium with a half-life of roughly one billion years is often used in radioactive dating. This isotope decays t

melisa1 [442]

Answer : The chemical symbol for the element that results from this process is, (Ar) for argon.

Explanation :

Electron capture : In this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. Simply, a proton and an electron combines together to form a neutron. Mass number does not change in this process.

$_Z^A\textrm{X}+_{-1}^0\textrm{e}\rightarrow _{Z-1}^A\textrm{Y}$

The equation for the given reaction is,

$_{19}^{40}\textrm{K}+_{-1}^0\textrm{e}\rightarrow _{18}^{40}\textrm{Ar}$

Thus, the chemical symbol for the element that results from this process is, argon (Ar).

7 0

3 years ago

Select all that apply to physical and chemical properties ?

MaRussiya [10]

Answer:

• Chemical properties can only be observed during a chemical reaction:

Chemical properties can only be established by changing a substance's chemical identity, and chemical properties are different from physical properties, which can be observed by viewing or touching a sample. The internal qualities of a substance must be altered to determine its chemical properties.

Examples:

Some common chemical properties are heat of combustion, enthalpy of formation, toxicity,

and flammability, each of which will be covered in this lesson.

• Rusting of iron is the chemical reaction not physical because:

The rusting of iron is a chemical change because it is two substances reacting together to make a

new substance. When iron rusts, iron molecules react with oxygen molecules to make a compound

called iron oxide. Rusting would only be a physical change if iron molecules remained pure iron

throughout the process.

The equation for this reaction is: 4Fe+ 3O2 → 2Fe2O

• Melting and boiling points are physical properties:

Yes melting and boiling points are the physical properties.

Physical properties can be observed or measured without changing the composition of matter. Physical properties are used to observe and describe matter.

Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.

• Mass and volume are chemical properties:

No mass and volume are the extensive physical properties of matter

All properties of matter are either physical or chemical properties and physical properties are either intensive or extensive.

Extensive properties, such as mass and volume, depend on the amount of matter being measured.

Intensive properties, such as density and color, do not depend on the amount of the substance present.

Physical properties can be measured without changing a substance’s chemical identity.

• Various components of a mixture do not combine chemically:

When various components of a mixture do not combine chemically it is a Combination of substances in which individual components do not combine chemically but retain their individual properties. Mixture in which one or more substances are distributed evenly in another substance.

When various components combine chemically then form chemical compounds that are often divided into two categories. Metals often react with nonmetals to form ionic compounds. These compounds are composed of positive and negative ions formed by adding or subtracting electrons from neutral atoms and molecules

7 0

3 years ago

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