Pls answer! 30 points and brainliest for the correct answer!

Complete question is;

Consider this reaction: 2 HI(g) ⇄ H₂(g) + I₂(g)

At a certain temperature, this reaction follows first - order kinetics with a rate constant of 0.684 s^(-1). Suppose a vessel contains HI at a concentration of 0.32 M. Calculate the concentration of HI in the vessel 0.88 seconds later.

You may assume no other reaction is important.

Round your answer to 2 significant digits

Answer:

0.18 M

Explanation:

We are given;

Initial concentration of HI = 0.32 M

Time = 0.88 s

Rate is given as 0.684 s^(-1)

Now, we want to find the concentration of HI in the vessel 0.88 seconds later. It can be gotten from the formula;

ln (HI) = ln (HI)₀ - (kt)

Where;

(HI)₀ is the initial concentration

k is the reaction rate constant

t is time

Plugging in the relevant values, we have;

ln (HI) = In (0.32) - (0.684 × 0.88)

ln (HI) = -1.1394 - 0.6019

ln (HI) = -1.7413

(HI) = e^(-1.7413)

(HI) = 0.175 M ≈ 0.18 M

Answer:

[tex]\%Ca=38.76\%[/tex]

Explanation:

Hello.

In this case, since percent compositions are computed by knowing the number of atoms of the required atom, its atomic mass and the molar mass of the compound at which it is, thus, for calcium we have:

[tex]\%Ca=\frac{3*m_{Ca}}{M_{Ca_3(PO_4)_2}} *100\%[/tex]

Thus, since calcium weights 40.08 g/mol and calcium phosphate 310.2 g/mol, the by mass percent of calcium turns out:

[tex]\%Ca=\frac{3*40.08g/mol}{310.2g/mol} *100\%\\\\\%Ca=38.76\%[/tex]

Best regards!

Answer:

The water is impure

Explanation:

Impurities raises the boiling points and lowers the melting point

Answer:

Correct Answer: B.  (60⋅12)+(40⋅13)

Explanation:

Answer:

Answer choice C

Explanation:

Basicly for the Arrhenius and Bornsted-Lowery theories of acids & bases, acid-base reactions can be divided into 4 forms...

a. Strong Acid + Strong Base (HCl/NaOH) => pH = 7 at Eqv. Pt.

b. Weak Acid + Strong Base (HOAc/NaOH) => pH > 7 at Eqv. Pt.

c. Strong Acid + Weak Base (HCl & NH₄OH) => pH < 7 at Eqv. Pt.

d. Weak Acid + Weak Base (HOAc & NH₄OH) => pH ∝ Stronger Electrolyte

*HOAc = Acetic Acid

*NH₄OH = Ammonium Hydroxide

For each type reaction the pH at equivalence point depends upon the salt generated by the acid-base reaction. Ions of the salt, if they react with water, (hydrolysis) will shift the pH up or down depending upon which ion reacts. If there is no reaction by the salt ions then the pH will depend only upon autoionization of water which gives pH = 7. Typically Strong Acids + Strong Bases will give a pH = 7 at equivalence point because the ions of the salt will not undergo hydrolysis in water.

Example:

Strong Acid + Strong Base

HCl(aq) + NaOH(aq) => NaCl(aq) + H₂O(l)

NaCl(aq) => Na⁺(aq) + Cl⁻(aq)

Na⁺(aq) + H₂O(l) => No Rxn (theoretically NaOH, but NaOH is a strong base which prefers to remain 100% ionized in water).

Cl⁻(aq) + H₂O(l) => No Rxn (theoretically HCl, but HCl is a strong acid which prefers to remain 100% ionized in water).

Therefore, the net rxn is H⁺ + OH⁻ => H₂O & pH = 7.0

Weak Acid + Strong Base

HOAc(aq) + NaOH(aq) => NaOAc(aq) + H₂O(l)

NaOAc(aq) => Na⁺(aq) + OAc⁻(aq)

Na⁺(aq) +  H₂O(l) => No Rxn

OAc⁻(aq) +  H₂O(l) => HOAc(aq) + OH⁻(aq) => (Excess OH⁻ functions to increase pH>7 at eqv. pt.)

Strong Acid + Weak Base

HCl(aq) + NH₄OH(aq) => NH₄Cl(aq) + H₂O(l)

NH₄Cl(aq)  => NH₄⁺(aq) + Cl⁻(aq)

Cl⁻(aq) + H₂O(l) => No Rxn

NH₄⁺(aq) + H₂O(l) => NH₄OH(aq) + H⁺(aq) => (Excess H⁺ functions to decrease pH < 7 at eqv. pt. )

Answer:

B

Explanation:

Answer:

kisses

Explanation:

mwah

Answer:

1. If an atom of calcium has a mass of 40:

a. Protons = 20

b. Neutrons = 20

2. If an atom of krypton has a mass of 84:

a. Protons = 36

b. Neutrons = 48

3. If an atom of tin has a mass of 119:

a. Protons = 50

b. Neutrons = 69

4. If an atom of tungsten has a mass of 184:

a. Protons = 74

b. Neutrons =110

Explanation:

kinetic energy?? idek hope I helped in anyway possible

Answer:

7.5 joules also 7.5 J

Explanation:

Answer:

This question is incomplete

Explanation:

This question is incomplete, however, there are some basic things that be used to answer the completed question on your own. Flame test is a test that is used to identify metal ions in a compound. Although, not all metal ions produce a colour in a flame test.

In a flame test, a "clean wire loop" is dipped in an unknown solid/mixture of solids, the loop where the solids must have attached to is then placed in the tip of a blue flame (perhaps of a bunsen burner). A colour change/changes is then observed during the course of this process. Some popular metal ions and there colour in flame test are listed below

Lithium ion ⇒ red

Sodium ion ⇒ yellow

Potassium ion ⇒ lilac

Calcium ion ⇒ orange-red

Barium ion ⇒ pale-green

Copper ion ⇒ blue-green

rubidium ion ⇒ red-violet

Lead ion ⇒ gray white

The number of different colours observed will ultimately determine the number of elements exposed to the flame

Answer:

0.962 atm.

97.4 kPa.

731 torr.

14.1 psi.

97,434.6 Pa.

Explanation:

Hello.

In this case, given the available factors equaling 1 atm of pressure, each required pressure turns out:

- Atmospheres: 1 atm = 760 mmHg:

[tex]p=731mmHg*\frac{1atm}{760mmHg} =0.962atm[/tex]

- Kilopascals:: 101.3 kPa = 760 mmHg:

[tex]p=731mmHg*\frac{101.3kPa}{760mmHg} =97.4kPa[/tex]

- Torrs: 760 torr = 760 mmHg:

[tex]p=731mmHg*\frac{760 torr}{760mmHg} =731 torr[/tex]

- Pounds per square inch: 14.69 psi = 760 mmHg:

[tex]p=731mmHg*\frac{14.69}{760mmHg} =14.1psi[/tex]

- Pascals: 101300 Pa = 760 mmHg:

[tex]p=731mmHg*\frac{101300Pa}{760mmHg} \\\\p=97,434.6Pa[/tex]

Best regards.

Answer:

in Crystalline solids

Explanation:

Answer:

A. Reference blank

B. Cuvettes

C. Transmittance

D. Absorbance

E. Wavelength

Explanation:

A reference blank is a sample prepared using the solvent and any other chemicals in the sample solutions, but not the absorbing substance.

A square-shaped container, typically made of quartz, designed to hold samples in a spectrophotometer is known as Cuvettes.

A measurement of the amount of light that passes through a sample or percentage of light transmitted by the sample, with the respective intensities of the incident and transmitted beams is called Transmittance.

The measurement of the amount of light taken in by a sample is known as Absorbance

The wavelength is also the distance travelled by the wave during a period of oscillation. In spectrophotometry, the unit is inversely proportional to energy and commonly measured in nanometers

The sample that is prepared using the solvent and any other chemicals in the sample solutions, but not the absorbing substance is a reference blank.

A square-shaped container, typically made of quartz, designed to hold samples in a spectrophotometer is the cuvettes.

A measurement of the amount of light that passes through a sample is transmittance.

A measurement of the amount of light that is taken in by a sample is referred to as absorbance.

A unit that is commonly used in spectrophotometry that is inversely proportional to energy and commonly measured in nanometers is the wavelength.

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Answer: Grease; Clamp; Ring stand.

Explanation:

Distillation is being used while separating liquids from the nonvolatile solids, or in instance whereby there is a different boiling point between two or more liquids.

Before assembling a distillation apparatus, lubricate the ground glass joints of each piece of glassware using grease. This will help in lubricating the glass joints so that it won't squeeze out while under pressure.

This helps seal the connection between two components. Once two components are fit together, use clamp to make the connections secure. Clamp is a fastening device which will help in holding the components together so that they won't be separated.

Stabilize the complete distillation setup using a ring stand. The ring stand will help in the provision of support to the glassware.

Answer: 40.496%

Hope this helps! (:

Answer:

An ester of sulfuric acid in which only one sulfuric acid hydroxyl group has been esterified. The product of esterification of both sulfuric acid hydroxyl groups is a sulfate ester.

Answer:

When a physical change occurs, the arrangement of particles within the substance may change, but the atoms in the molecules remain bonded together.

Explanation:

Srry didn't see this till now, hope u got it right :)

Answer:

Wind erosion abrades surfaces and makes desert pavement, ventifacts, and desert varnish. Sand dunes are common wind deposits that come in different shapes, depending on winds and sand availability.

Answer:

5.80 mol He 6.02210^23 atoms He/ 1 mol He. This cancels out moles, leaving 3.49*10^24 atoms He. Mass is used as a method of counting atoms.

The number of atoms in 5.80 moles of He is equal to 3.49 × 10²⁴ atoms.

Avogadro’s number is used to represent the number of entities in one mole of any substance. Generally, these entities are ions, molecules, atoms, electrons, or protons, depending upon the type of reaction or reactant and product.

The value of Avogadro’s constant is found approximately 6.022 × 10²³ mol⁻¹. This number was named after the scientist Amedeo Avogadro after his death.

Given, the number of moles of helium = 5.80

The number of atoms in one mole of He = 6.022 × 10²³

The number of atoms on 5.80 moles of He = 5.80 × 6.022 × 10²³

Total number of atoms =  3.49 × 10²⁴

Therefore, the number of atoms in 5.80 moles of Helium is 3.49 × 10²⁴ He atoms.

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Answer:

D = M/V

Explanation:

D = 55.5g/11.5cm^3

D = 4.83g/cm^3

Answer:

water,salt are the house hold items

Answer:

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

From the question

volume = 22.5 mL

density = 0.23 g/mL

We have

mass = 0.23 × 22.5 = 5.175

We have the final answer as

Hope this helps you

Answer:

It would have to tp be "Energy is being transformed from one form to another".

Explanation:

The reason I know this is because energy can neither be created nor destroyed only transformed into new forms.

Answer:

Energy has been transferred from one form to another.

Explanation:

got it right

Answer:

the third one

Explanation:

if you look at it mathematically its the one that makes the most sense

Answer:

Explanation:

Then, multiply the number of moles of Na by the conversion factor 6.02214179×1023 atoms Na/ 1 mol Na, with 6.02214179×1023 atoms being the number of atoms in one mole of Na (Avogadro's constant), which then allows the cancelation of moles, leaving the number of atoms of Na.Aug 15, 2020

Answer:

The C-N bond is a double bond.

There is no free rotation about the C-N bond

Explanation:

Linus Pauling and Robert Corey carried out a painstaking study of the bond lengths of peptide bonds as well as the stereo chemistry of atoms and groups around the peptide bonds in the crystal structures of molecules containing one or a few peptide bonds.

Their findings indicate that the bond length of the C-N bond in crystalline peptides is intermediate in length (1.32 Å) between a typical C—N single bond (1.49 Å) and a C=N double bond (1.27 Å). This is because the peptide bond has some double bond character as a result of resonance involving the C=O and -NH moieties of the amide.

As a result of resonance as shown above, the peptide bonds are found to be planar hence free rotation about the C-N bond is hindered. The peptide bond is mostly found in the trans configuration because it is more energetically favourable than the cis configuration.

Summarily, owing to the existence of a partial double bond character between the α carbon and the amine nitrogen in the peptide, there is no free rotation around the C-N bond.

Answer:

D coarse texture

Explanation:

An igneous rock floats because air bubbles became trapped when molten material erupted from an underground volcano. This rock can be accurately described as extrusive and the correct option is option 2.

Igneous rocks (from the Latin word for fire) form when hot, molten rock crystallizes and solidifies. The melt originates deep within the Earth near active plate boundaries or hot spots, then rises toward the surface. Igneous rocks are divided into two groups, intrusive or extrusive, depending upon where the molten rock solidifies.

Igneous rocks can be easily identified with their texture, density, colour, and mineral composition. Its texture depends on the shape, size, time period to cool down and solidify, and the arrangement of crystals in the rock.

Therefore, an igneous rock floats because air bubbles became trapped when molten material erupted from an underground volcano. This rock can be accurately described as extrusive and the correct option is option 2.

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