A student dissolves 7.9 g of stilbene (C14H12) in 475. mL of a solvent with a density of 1.03 g/mL. The student notices that the volume of the solvent does not change when the stilbene dissolves in it. Calculate the molarity and morality of the students solution. Round both of your answers to 2 significant digits.

Answer:

the last one probably

Explanation:

Answer:

C. The mass stays the same because the total number of atoms does not change

Explanation:

According to the law of conservation of matter/mass, matter cannot be created nor destroyed, hence, the amount of matter in the reactants must be the same amount in the products.

Using the photosynthetic reaction as a case study, carbon dioxide (CO2) and water (H2O) are the compounds that go into the reaction (reactants) while glucose and oxygen (O2) are the products of the reaction.

Using the law of conservation of matter to explain, the total mass of both the reactants and products stays the same because the total number of atoms does not change i.e. if 6 atoms of Carbon starts the reaction, 6 atoms of carbon will end it.

Answer:

1.49 × 10⁹ years

Explanation:

Step 1: Calculate the rate constant (k) for the nuclear decay of U-235

The decay follows first-order kinetics with a half-life (t1/2) of 703 × 10⁶ years. We can calculate "k" using the following expression.

k = ln2/ t1/2 = ln2 / 703 × 10⁶ y = 9.86 × 10⁻¹⁰ y⁻¹

Step 2: Calculate the time elapsed (t) so that the final amount ([U]) is 23.0% of the initial amount ([U]₀)

For first order kinetics, we will use the following expression.

ln ([U]/[U]₀) = -k × t

ln (0.230[U]₀/[U]₀) = -9.86 × 10⁻¹⁰ y⁻¹ × t

ln 0.230 = -9.86 × 10⁻¹⁰ y⁻¹ × t

t = 1.49 × 10⁹ y

Answer:

2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g) + 248kcal

Explanation:

The reaction of the problem occurs as follows:

H2S(g) + O2(g) → H2O(g) + SO2(g)

To balance the reaction we must balance oxygens:

H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g)

To balance the complete reaction:

2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g)

As the energy is evolved, 124kcal are as product in the reactio per mole of H2S. As the balanced reaction contains 2 moles of H2S, the heat evolved is:

124kcal*2 = 248kcal:

2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g) + 248kcal

And this is the balanced equation

Answer:

Kf = 0.389.

Explanation:

Hello there!

In this case, it turns out possible for us to solve this problem by firstly writing the equilibrium chemical equation and equilibrium expression for the formation of this complex:

[tex]B+C\rightleftharpoons BC\\\\Kf=\frac{[BC]}{[B][C]}[/tex]

Thus, we firstly calculate the concentrations at equilibrium, knowing that the reaction extent in this case is 0.00500mol (same as the formed moles of BC):

[tex][B]=[C]=\frac{0.0350L*1.00mol/L-0.00500mol}{0.0700L} =0.429M[/tex]

[tex][BC]=\frac{0.00500mol}{0.0700L} =0.0714M[/tex]

And finally, the equilibrium constant:

[tex]Kf=\frac{0.0714}{[0.429][0.429]}\\\\Kf=0.389[/tex]

Regards!

Answer:

C₄H₄N₂

Explanation:

Given that:

M+ = 80.

It implies that the number of nitrogen present in the molecule must also be even according to the Nitrogen rule.

So from the Formula CHN, the nitrogen will have to be 2 because if we make use of 4, it will exceed the given M+ which is 80.

∴

C₄ = 4 × 12 = 48

H₄  = 4 × 1   = 4

N₂ =  2 × 14 = 28      

                      80      

As such, the molecular formula of the compound is C₄H₄N₂

Answer:

1x10^-6

Explanation:

Answer:

50 CI₂ molecules

Explanation:

By looking at the stoichiometric coefficients, we can tell that if 2 atoms of potassium (K) react with chlorine gas (CI₂), 1 chlorine molecule would react.

With that in mind we can calculate how many CI₂ molecules would react with 100 K atoms:

Answer:

See explanation

Explanation:

TLC is a chromatographic method in which the solute is spotted on a plate and the plate is placed in an air tight chamber containing a solvent. The solvent is maintained below the level of the spot. The capillary movement of the solvent through the plate achieves the required separation.

If two spots have Rf values of 0.25 and 0.26 respectively and then the plate was removed from the developing chamber, subsequently, the residual solvent was allowed to evaporate from the plate, and then the plate was returned to the developing chamber.

It will be observed after the second development is complete that the new Rf values will be 0.50 and 0.52 respectively. It will just be as though the second chromatogram picked up from where the first chromatogram stopped.

Answer:

Hence,  

1) removed  

2) drained through the stopcock  

3) get eye level with  

4) slow the draining  

5) switch to a new flask

Explanation:

After mixing the solutions in a separatory funnel, the stopper should be removed and the liquid should be drained through the stopcock, and the layers allowed to separate. When you get close to the interface between the layers, get eye level with the funnel and turn over to slow the draining heat up until the first layer is collected. Switch to a new flask get eye level with it to collect the second layer.

Answer:

6.02 × 10²⁷ km

Explanation:

Step 1: Calculate the height of the stack of pennies

A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro's number of pennies (6.02 × 10²³ pennies) one on top of the other on Earth's surface, the height of the stack of pennies would be:

6.02 × 10²³ pennie × 1.0 mm/1 pennie = 6.02 × 10²³ mm

Step 2: Convert 6.02 × 10²³ mm to kilometers

We will use the following conversion factors.

6.02 × 10²³ mm × 1 m/10³ mm × 1 km/10³ m = 6.02 × 10²⁷ km

Answer:

[tex]{ \tt{22.4 \: dm {}^{3} \: contains \: 1 \: mole \: of \: hydrogen }} \\ { \tt{0.15 \: {dm}^{3} \: will \: contain \: ( \frac{0.15}{22.4} \times 1) \: moles }} \\ = 0.0067 \: moles \\ { \bf{mole \: ratio = 1 :1 }} \\ { \tt{1 \: mole \: weighs \: 65.38 \: g}} \\ { \tt{0.0067 \: moles \: weighs \: (0.0067 \times 65.38) \: g}} \\ = 0.44 \: g[/tex]

Answer:

-0.08 °C

Explanation:

We can solve this problem by using Charles' law, which states that at constant pressure:

Where in this case:

We input the data:

And solve for T₂:

Finally we convert 273.08 K to Celsius:

Answer:

(a) The moles of CuSO₄ is 3.125 × 10⁻³ moles.

(b) The moles of Cu is 3.125 × 10⁻³ moles.

(c) The mass of Cu is 0.2 g.

Explanation:

Given:

Mass of CuSO₄ = 0.5 g

Molar mass of CuSO₄ = 160 g/mol

The given balanced chemical equation is:

[tex]2Al+3CuSO_4\rightarrow 3Cu+Al_2(SO_4)_3[/tex]

Part (a):

Calculating the moles of CuSO₄.

[tex]\text{Moles of } CuSO_4=\frac{\text{Mass of }CuSO_4}{\text{Molar mass of }CuSO_4}\\\\\text{Moles of } CuSO_4=\frac{0.5g}{160g/mol}\\\\\text{Moles of } CuSO_4=3.125\times 10^{-3}mol[/tex]

Thus, the moles of CuSO₄ is 3.125 × 10⁻³ moles.

Part (b):

Calculating the moles of Cu.

From the balanced chemical equation, we conclude that:

As, 3 moles of CuSO₄ reacts to give 3 moles of Cu

So, 3.125 × 10⁻³ moles of CuSO₄ reacts to give 3.125 × 10⁻³ moles of Cu

Thus, the moles of Cu is 3.125 × 10⁻³ moles.

Part (c):

Calculating the mass of Cu.

Mass of Cu = Moles of Cu × Molar mass of Cu

Molar mass of Cu = 64 g/mol

Mass of Cu = (3.125 × 10⁻³ mole) × (64 g/mol)

Mass of Cu = 0.2 g

Thus, the mass of Cu is 0.2 g.

Answer:

It is D).cyclohexanone ( in acellus)

Explanation:

Explanation:

ethoxypropane

Ch3-ch2-o-ch2-ch2-och3

Answer:

See explanation

Explanation:

The atomic number refers to the number of protons in the nucleus, it also tells us the number of electrons in the neutral atom since the atom is electrically neutral because the number of protons and electrons are equal.

If an atom has the atomic number 11, then the electrons in the atom are arranged in the shells in the order; 2, 8, 1.

Two electrons are found in the innermost shell, eight electrons are found in the next shell and one electron is found on the outermost shell.

The nucleus of the atom is composed of a total of 23 nucleons; 11 protons and 12 neutrons.

Answer:

liquid is the right answer k

Answer:

liquid

Explanation:

Answer:

Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.

It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.

A process such as a chemical reaction that removes water.The atoms which constitute the molecule of water that is removed.

Hence,It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent,

Thus, it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.

Learn  more about reactions here ;

https://brainly.com/question/17434463

#SPJ2

Explanation:

1. As you go across a period, what is a useful comparison point?

A.

oxides

2. Most elements are

A.

allotropes

3. A metalloid is a(n) __ conductor of heat and electricity than a metal.

A.

better

4. What causes the formation of allotropes?

A.

pressure

As you move __and __ elements become more metallic.

A.

left, down

5. All of the following metalloids form allotropes except

A.

B

6. What is a chemical property of a metal?

A.

malleable

Answer:

Alkanes

Cycloalkanes

Ring flip

Lower

Angle

Equatorial

Axial

Explanation:

For alkanes, the general molecular formula is CnH2n+2 while for cycloalkanes, the general molecular formula is CnH2n.

The cycloalkanes could undergo a ring flip in which axial and equatorial hydrogen atoms are interconverted.

The lower energy conformation of alkanes is the anti conformation and not the gauche conformation due to steric strain.

When the bond angle in alkanes deviate from the ideal 109.5°, an angle strain has occurred.

For bulky groups, the equatorial position his preferred since it has more room than the axial position.

Answer:

100 mL

Explanation:

The reaction that takes place is:

First we convert 500 mg of CaCO₃ into mmoles, using its molar mass:

Then we convert 5 mmoles of CaCO₃ into HCl mmoles, using the stoichiometric coefficients of the balanced reaction:

Finally we calculate the volume of a 0.10 M HCl solution (such as stomach acid) that would contain 10 mmoles:

Answer:

H+

Explanation:

it's H+

as you see hydrogen ion it could H+

Answer:

See explanation

Explanation:

I) from the question;

500 × 10^-3 g dissolves in 100ml

xg dissolves in 1000ml

x = 500 × 10^-3 g × 1000ml/100 ml

x= 5 g/L

Mass concentration = molar concentration × molar mass

Molar concentration = Mass concentration/ molar mass

Molar concentration = 5g/L/419 g/mol

Molar concentration = 0.0119 M

ii) To prepare this solution, measure out 500mg with a weighing balance. Transfer the solid to a standard 100 ml volumetric flask. Make up to the 100ml mark with distilled water.

iii) mass concentration of the solution = 50 g/L

Volume of the solution= 100 ml

Mass of the solid = 50 g/L × 100/1000 L

Mass of solid = 5g

This 5g was taken for 10 days, hence a total of 50 g

Since the normal dose of the drug is 40g for ten days, the patient will suffer from kidney problems because he/she has taken the drug above the recommended dosage.

1 NaCl + 1 HCl ➡️ 1 NaCl + Water (H2O) .

Explanation:

[tex]2H_2O_2 \rightarrow 2H_2O + O_2[/tex]

First convert the amount of water into moles:

360 g H2O × [tex]\left(\dfrac{1\:\text{mol}H_2O}{18.015\:\text{g}H_2O}\right)[/tex]

[tex] = 20. \:\text{mol}H_2O[/tex]

Now let's calculate the number of moles of O2 gas produced.

20 mol H2O × [tex]\left(\dfrac{1\:\text{mol}O_2}{2\:\text{mol}H_2O}\right)=10\:\text{mol}O_2[/tex]

The volume of gas at 10°C and 5 atm can be found using the ideal gas law:

[tex]PV=nRT[/tex]

[tex]V= \dfrac{nRT}{P}[/tex]

[tex]= \dfrac{(10)(0.082)(283)}{(5)}=46.4\:L[/tex]

It last longer because it slows down the spread of bacteria.

Temperature, concentration, particle size, use of a catalyst.

Answer: hello some part of your question is missing below is the missing part

In an experiment to determine the % of ascorbic acid in Vitamin C Tablets by Titration with Potassium Bromate,

answer:

Oxidation half reaction of Vitamin C

Explanation:

The solution will turn cloudy dark purple even after reaching endpoint when allowed to settle with time. because of the Oxidation half reaction of Vitamin C. also during the Titration process few drops of starch solution will be added to help determine the endpoint of the experiment .

Answer:

"The total pressure in a mixture of gases is equal to the sum of partial pressures of each gas"

Explanation:

Dalton's law of partial pressures state that, in a mixture of gases, the total pressure is equal to the sum of the partial pressure exerted by each gas of the mixture. The equation is:

Total pressure = Partial pressure Gas 1 + Partial pressure Gas 2 + .... + Partial pressure Gas n

To complete the sentence we can say:

"The total pressure in a mixture of gases is equal to the sum of partial pressures of each gas"

Considering the Dalton's partial pressure, the total pressure in a mixture of gases is equal to the sum of partial pressures of each gas.

The pressure exerted by a particular gas in a mixture is known as its partial pressure. So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:

[tex]P_{T} =P_{A} +P_{B}[/tex]

This relationship is due to the assumption that there are no attractive forces between the gases.

Dalton's partial pressure law can also be expressed in terms of the mole fraction of the gas in the mixture. The mole fraction is a dimensionless quantity that expresses the ratio of the number of moles of a component to the number of moles of all the components present.

So in a mixture of two or more gases, the partial pressure of gas A can be expressed as:

[tex]P_{A} =x_{A} P_{T}[/tex]

In summary, the total pressure in a mixture of gases is equal to the sum of partial pressures of each gas.

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