N2O4(g) + 4H2(g) → N2(g) + 4H2O(g), solve using standard enthalpies of formation

Explanation:

select the correct answer from each drp down

2.99 °C is the change in temperature if a 40 g sample of water absorbs 500 calories of energy.

The specific heat capacity is defined as the quantity of heat (J) absorbed per unit mass (kg) of the material when its temperature increases 1 K (or 1 °C), and its units are J/(kg K) or J/(kg °C).

Given data:

m = 40 g

Q = 500 J

Specific heat capacity of water = 4.18 J/g°C

Change in Temperature =?

The formula for Heat Energy is given by:

Q = mcp∆T

where: Q - Heat Energy

m - mass

cp - specific heat

∆T = change in temperature, [tex]T_2 - T_1[/tex]

Solution:

Substituting the value of m, specific heat capacity of water and Q in the formula,

500 J = (40 g)(4.18 J/g°C)(∆T)

∆T = 2.99 °C

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Answer:

A.DNA

Explanation:

Ahaa Its gona be right

Answer:

D.N.A.

Explanation:

Hi student! Let me help you out on this question.

D.N.A. is the molecule which carries instructions for inherited traits.

[tex]\therefore,Option\quad A \quad is \quad correct[/tex]

Hope that this helped! have a good day ahead.

After Rounding off The percentage yield is 64%

It is the ratio of actual yield to theoretical yield multiplied by 100% .

It is given in the question

20.0 g of bromic acid, HBrO3, is reacted with excess HBr.

The reaction is

HBrO₃ (aq) + 5 HBr (aq) → 3 H₂O (l) + 3 Br₂ (aq)

Actual yield = 47.3 grams

Molecular weight of Bromic Acid is 128.91 gram

Moles of Bromic Acid = 20/128.91 = 0.155 mole

Mole fraction ratio of Bromic Acid to Bromine is 1 :3

Therefore for 0.155 mole of Bromic Acid 3 * 0.155 = 0.465 mole of Bromine is produced.

1 mole of Bromine = 159.8 grams of Bromine

0.465 of Bromine = 74.31 grams of Bromine

Percentage Yield = (47.3/74.31)*100 = 63.65 %

After Rounding off The percentage yield is 64% .

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Answer:

74g

Explanation:

The other person had said that the Percentage Yield = (47.3/74.31)*100 = 63.65 %

So, since to find the percent yield you have to divide the actual yield by the theoretical yield, I would assume the theoretical yield is 74.31g (74g if you round to the nearest gram)

Answer:

M=93.5g/mol

Explanation:

I did this in class and it was a review. :)

The weak base ionization constant (Kb) for [tex]CH_3NH_2[/tex] is equal to

[tex]Kb = [CH_3NH^{3+}] [OH^-] / [CH_3NH_2][/tex]

Kb is the base dissociation constant.

The expression for the equilibrium constant, Kb is simply the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient.

[tex]CH_3NH_2(aq) + H_2O(l)[/tex]  → [tex]CH_3NH^{3+}(aq) + OH^- (aq)[/tex]

Thus, the expression for the equilibrium constant, Kb fo the above reaction can be written as follow:

[tex]Kb = [CH_3NH^{3+}] [OH^-] / [CH_3NH_2][/tex]

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Answer:

V⬇2=64.mL this is the answer and the 2 is supposed to be at the bottom which the arrow stands for so do not put the arrow with that

Volume=1600cm³=1.6dm³=1.6L

Temperature=25°C=273+25=298K

Pressure=75000Pa

Now

Apply ideal gas equation

The number of moles needed is

n=48.43mol.

Calculations

Given the values of the volume and temperature, we would convert them to the required units.

Volume=1600cm³=1.6dm³=1.6L

Temperature=25°C=273+25=298K

Pressure=75000Pa

We would use the ideal gas equation

PV=nRT

n=PV/RT

n=75000(1.6)/8.314(298)

n=48.43mol

Explanation:

1 moles Lead(II) Acetate to grams = 325.28804 grams

3.47 moles Lead(II) Acetate to grams = 325.28804 ×3.47 grams=1128.749 grams

1 moles sodium chloride to grams=58.5 grams

3.47 moles sodium chloride to grams=58.5×3.47 grams

=202.995 grams

Answer:

=2007.69 Torr

Explanation:

The new pressure of helium gas assuming constant temperature is equal to 2007.69

Torr.

Given the following data:

Initial volume = 293 mL

Final volume = 0.115 L

Initial pressure = 788 Torr

Temperature = 25°C.

Conversion:

Initial volume = 293 mL to L = 293/1000=0.293L

To determine the new pressure assuming constant temperature, we would apply Boyle's law:

Mathematically, Boyle's law is given by the formula;

PV=K

P1V1=P2V2

Where;

P1 is the original (initial) pressure.

P2 is the final pressure.

V1 is the original (initial) volume.

V2 is the final volume.

Substituting the given parameters into the formula, we have;

788×0.293 = P2 × 0.115

230.884 = 0.115P2

P2 = 230.884/0.115

P2 =2007.69

Answer:

About energy transfers:

Explanation:

When there is an energy transfer energy is neither created, nor destroyed. This means when that when one energy store decreases, one or more others must increase.

345678990098765435779999999999999999995699999

42.4 ml is the volume in milliliters of the lead ball if a lead ball is added to a graduated cylinder containing 50.6 ml of water.

A tall narrow container with a volume scale is used especially for measuring liquids.

The graduated cylinder contains water

mL is a volume unit.

Water volume = 50.6 ml

The lead ball caused an increase in volume from 50.6 ml to 93.0 mL.

The new volume is the lead ball volume plus the original water volume :

Final volume = Vlead ball+ Water original volume

[tex]93.0 mL= V_(lead ball) +50.6 ml[/tex]

[tex]V_(lead ball) = 93.0 mL - 50.6 ml[/tex]

[tex]V_(lead ball) = 42.4 ml[/tex]

Hence, 42.4 ml is the volume in milliliters of the lead ball.

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A negative enthalpy (ΔH)for a molecule means energy was released when the molecule went through a phase change.

The enthalpy change of a reaction is the amount of heat absorbed or released as the reaction takes place.

Also, the amount of energy required to change the phase of a material is known as the enthalpy,

A negative enthalpy entails the amount of energy released during an exothermic reaction.

Thus, a negative enthalpy (ΔH)for a molecule means energy was released when the molecule went through a phase change.

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Answer: B. [tex]\text{CH}_{3}\text{COO}^{+}[/tex]

Explanation:

To find the conjugate base, you add a hydrogen ion and add 1 to the overall charge.

CH[tex]_3[/tex]COO⁻ is the conjugate base of  CH[tex]_3[/tex]COOH in the given reaction. Therefore, the correct option is option B.

Conjugate acids and bases are ideas included in the Bronsted-Lowry acid-base theory. An acid losses a hydrogen ion as it splits into its electrons in water. The conjugate base of the acid is the species that results.

A conjugate base comprises the base participant, X-, of two compounds that convert into one another by acquiring or losing a proton, according to a more comprehensive definition. In a chemical process, the conjugate base has the capacity to either gain and absorb a proton. The proton and hydrogen is given away in the process by the conjugate acid. CH[tex]_3[/tex]COO⁻ is the conjugate base of  CH[tex]_3[/tex]COOH in the given reaction.

Therefore, the correct option is option B.

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Answer:

283 grams KCl

Explanation:

To convert form moles to grams, you need to find the molar mass of your compound. The molar mass can be calculated using the individual molar masses of each element in the compound. These values can be found on the periodic table.

Molar Mass (K) = 39.098 g/mol

Molar Mass (Cl) = 35.453 g/mol

Molar Mass (KCl) = 39.098 g/mol + 35.453 g/mol

Molar Mass (KCl) = 74.551 g/mol

Now that you know the molar mass, you want to multiply it by the moles of KCl. This is possible because the molar mass is actually a ratio representing the relationship of grams and moles. In KCl, there are 74.551 grams of KCl for every 1 mole of KCl. When you are multiplying, make sure you set the ratio up in a way that allows for the units to cancel out and leave grams as your final answer.

3.80 moles KCl           74.551 g
-----------------------  x  -------------------  = 283 grams KCl
                                  1 mole KCl

The final answer should have 3 sig figs because the value the problem gave (3.80 mol) also has 3 sig figs.

Benzene be B

Toluene be T

We have made then one lettered to make things easier

[tex]\\ \rm\Rrightarrow \dfrac{P^0_B-P_B}{P^0_B}=x_B[/tex]

[tex]\\ \rm\Rrightarrow 95.1-P_B=95.(0.5)[/tex]

[tex]\\ \rm\Rrightarrow 95.1-P_B=47.55[/tex]

[tex]\\ \rm\Rrightarrow P_B=47.55mmHg[/tex]

And

[tex]\\ \rm\Rrightarrow \dfrac{P^0_T-P_T}{P^0_T}=x_T[/tex]

[tex]\\ \rm\Rrightarrow 28.4-P_T=28.4(0.5)[/tex]

[tex]\\ \rm\Rrightarrow P_T=14.2mmHg[/tex]

Total vapour pressure

Answer:

Here's your answer.

M(C3H8) = 44 g/mol

n(C3H8) = 5000 (g)/44 (g/mol) = 113,6 mol

[tex] N = n \times N_{a} = 113,6 \times 6,02 \times {10}^{23} \\ \\ = 684,1 \times 10 ^{23} \sf{molecules} [/tex]

In order to prepare a 50-fold diluted enzyme, 0.1 mL of the stock solution of the enzyme is taken and made up to 5.0 mL with 0.001M HCl.

Dilution is a process whereby a solution of lower concentration is prepared from one of a higher concentration.

Dilution is done by using the dilution formula below:

C1; Initial concentration of enzyme = 1 mg/mL

C2; Final concentration of enzyme = 1/50 mg/ml = 0.02 mg/ml

V1; Initial volume of enzyme = y

V2; Final volume = 5.0 ml

V1 = C2V2/C1

V1 =  0.02 * 5/1 = 0.1 mL

Therefore, in order to prepare a 50-fold diluted enzyme, 0.1 mL of the stock solution of the enzyme is taken and made up to 5.0 mL with 0.001M HCl.

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Answer:

about 3

Explanation:

just did this for the points just being honiest

Answer: 25.1195 L

Explanation:

Given:

There are 0.5860 mol of Iron powder (Fe)

The volume of oxygen gas at STP is 31.5 L

The volume filled by a gas at STP is approximately 22.71 L

Therefore, the moles of oxygen gas at STP = Volume of oxygen gas at STP/ 22.71

= 35.1/22.71

= 1.5456 mol

The balanced chemical equation given for this reaction is:

4Fe(s) + 3O2 (g) ----> 2Fe2O3 (s)

Dividing the above equation by 2, yields:

2Fe(s) + 3/2O2(g) -------> Fe2O3 (s)

From the equation we see:

2 moles of Fe reacts with 3/2 mole of O2 to give one mole of Fe2O3

Thus, let x moles of O2 react with 0.5860 moles of Fe

0.5860/2=x/3/2

0.5860*3=4*x

x = 1.758/4

x =0.4395 mol

So the remaining moles of oxygen gas = 1.5456 - 0.4395

= 1.1061 mol

Therefore, the amount of oxygen gas, in litres, remaining is = 1.1061*22.71

= 25.1195 L

Answer: 9.27 g/mL

Explanation:

[tex]d=\frac{m}{v}=\frac{18.53}{2.0}=\boxed{9.27 \text{ g/mL}}[/tex]

D

Explanation:

B/c both the hydrogen and chlorine have the same valance number so if a metal or non metal have the same valance number you should cancel out the numbers and you will have to put only the non metal or metals.

The volume of the unit cell is 2.67 x 10⁻²⁸ m³.

In a body-centered cubic unit cell, the volume occupied by the particles of the substance is about 68% of the total unit cell.

Assuming that a single atomic a sphere, the volume is:

Volume(atom) = 4/3 x π x r³

Volume(atom) = 4/3 x π x (169 x 10⁻¹²)³

Volume(atom) = 2.02 x 10⁻²⁹ m³

There are a total of 9 atoms in a body-centered unit cell, so the total volume occupied by atoms is:

2.02 x 10⁻²⁹ x 9

= 1.82 x 10⁻²⁸ m³

Volume of cell = (1.15 x 10⁻²⁸ ) / 0.68

Volume of cell = 2.67 x 10⁻²⁸ m³

Therefore, the volume of the unit cell is 2.67 x 10⁻²⁸ m³.

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Answer:

1940K and 1939K Isotopes are two forms of the same element that have different numbers of neutrons in the nucleus. This means same symbol, and same atomic number (subscript), but different mass number (superscript).

In one trial, the unique rate of reaction was 6.93 μmol⋅L−1⋅s−1, the initial rate is 17.4 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex] and rate of formation of sulfate ions was 11.6 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

Reaction rate, in chemistry, is the speed at which a chemical reaction proceeds.

[tex](S_2O_8)^-^2 (aq) + 3 I^-(aq)[/tex] → [tex]2 S0_4^-^2 (aq) + 3I^- (aq)[/tex]

Rate of the reaction = -Δ [[tex]S_20_8^-^2[/tex]] /Δ t = -1/3 Δ [[tex]I^-[/tex]] /Δ t

5.8  μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex] = -1/3 Δ [[tex]I^-[/tex]] /Δ t

-Δ [[tex]I^-[/tex]] /Δ t =17.4 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

So the rate of reaction of iodide ion =17.4 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

+1/2Δ [[tex]S0_4^-^2[/tex]] /Δ t  = rate of reaction

+1/2Δ [[tex]S0_4^-^2[/tex]] /Δ t  = 5.8 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

+ Δ [[tex]S0_4^-^2[/tex]] /Δ t  = 5.8 X 2 = 11.6 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

Rate of formation of sulfate ions=11.6 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

Hence, the initial rate is 17.4 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex] and rate of formation of sulfate ions was 11.6 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

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Answer:

C. It is the ratio of the concentrations of products to the

concentrations of reactants.

Explanation:

From the calculations, we can see that the theoretical yiled of NO2 is 100L of NO2

The theoretical yield is that calculated from the stoichiometry of the reaction.

We can see that 1 mole of O2 produced 2 moles of NO2. Thus;

2.23 moles of O2 will produce 4.46 moles of NO2

Since 1 mole of NO2 occupies 22.4 L

4.46 moles of NO2 occupies 100L of NO2

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No of molecules=26.02×10²³molecules

No of moles

Molar mass

Mass

[tex]\\ \tt{:}\longrightarrow No\:of\:moles=\dfrac{Molecules}{Avagadro\:no}[/tex]

[tex]\\ \tt{:}\longrightarrow No\:of\:moles=\dfrac{26.02\times 10^{23}}{6.023\times 10^{23}}[/tex]

[tex]\\ \tt{:}\longrightarrow No\:of\:moles=4.32mol[/tex]

We need the mass

[tex]\\ \tt{:}\longrightarrow No\:of\:moles\times molar\:mass[/tex]

[tex]\\ \tt{:}\longrightarrow 32(4.32)[/tex]

[tex]\\ \tt{:}\longrightarrow 138.24g[/tex]

Answer:

hello :)

Explanation:

Water vapor in the air reaches its dew point as it cools in the air around the can, forming liquid drops of water. Condensation is the process where water vapor becomes liquid.