What element is depicted by the following electron configuration:

(The electron configuration is in the image)




A. None of these
B. Oxygen
C. Chlorine
D. Sulfur

Answer:

The correct answer is 15.54 kJ per degree C.

Explanation:

The enthalpy change for one mole of a substance, which combines or burns with the oxygen under the standard conditions, that is, at 25 degree C and 1 bar pressure is known as the standard molar enthalpy of combustion. The amount of heat transferred can be calculated by using the formula, q = mcΔT -------------(i)

Here q is the amount of heat transferred, c is the specific heat, ΔT is the change in temperature, and m is the mass of the substance. As in case of bomb calorimeter, mass if considered constant, thus, for calorimeter the equation mentioned will become, q = cΔT ---- (ii)

The standard molar enthalpy of combustion for carbon is -393.5 kJ/mol, that is, -393.5 kJ per mole of heat is generated by burning one mole of carbon. The molecular mass of carbon is 12 gram per mole.  

Thus, the number of moles of carbon equivalent to 0.562 grams of carbon can be determined as,  

Number of moles of carbon = mass / molecular mas

= 0.562 grams / 12 gram per mole

= 0.047 mol

The heat generated by burning 0.562 grams or 0.047 mole will be,  

q = ΔH° × number of moles

= (-393.51 kJ/mol) × 0.047 mol

= -18.49 kJ, the negative sign shows that the heat is produced.  

To find heat capacity of calorimeter, put the value of q as -18.49 kJ, for ΔT as (27.93 °C - 26.74 °C) in the equation (ii)

18.49 kJ = c × (27.93 - 26.74)

c = 18.49 kJ/1.19 °C

c = 15.54 kJ/°C

Answer: burning paper

Explanation:

The paper burns in air to form smoke and ash. which makes it a chemical change.

Answer:

Below is the clarification of that same particular question.

Explanation:

For that kind of weak diprotic predictor, the standard economic statement can indeed be published as:

    ⇒  [tex]H_2In_(aq)\rightleftharpoons In^{2-} +2H^+[/tex]

Answer:

(ii) Ethane and Heptadecane

Explanation:

The separation of all the species listed in the answer options for the question depends on the molar mass of each specie.

Ethane is a low molecular mass gas. It exists in the gaseous state at room temperature. However, heptadecane appears as a liquid because it has a greater relative molecular mass.

It is very easily to distinguish between the gas, ethane and the liquid heptadecane which is a high molecular mass alkane, hence the answer.

There would be an increase in the concentration of carbonic acid - this is how an increase in carbon dioxide concentration influences the system.

In chemistry, a dynamic equilibrium lives once a reversible reaction occurs. Substances transition between the reactants and products at equal rates, indicating there is no net change. Reactants and products exist formed at such a rate that the concentration of neither changes. It is a precise example of a system in a steady state. After a time, a reversible reaction in a closed system can get what we call a dynamic equilibrium.

The correct answer is option D.

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Answer:

D. A combustion reaction

Explanation:

Answer:

The answer is 97.2g .

Explanation:

Given that 1 mL is equals to 1 cm². Then we have to apply Density formula :

[tex]density = \frac{mass}{volume} [/tex]

[tex]let \: density = 2.7 \: , \: volume = 36[/tex]

[tex]2.7 = \frac{mass}{36} [/tex]

[tex]mass = 2.7 \times 36[/tex]

[tex]mass = 97.2 \: grams[/tex]

Answer:

Alkalai B

Explanation:

B because its a weak alkali ie baking soda ph 8.3(sodium bicarbonate)which is used as a remeady of heartburns and stomach acids.

Answer:

The answer is "Option B"

Explanation:

From the query, the following knowledge is derived:  

Yield in percentage = 47%  

Performance of theory = 4860 g  

Actual yield Rate =?  

The percentage return is defined simply by the ratio between both the real return as well as the conceptual return multiplied by the 100. It's also represented as numerically:

[tex]Rate = \frac{Existing \ Rate} {Theoretical \ Rate} \times 100[/tex]

Now We can obtain the percent yield as followed using the above formula:  

[tex]\text{Yield in percentage}= \frac{Actual \ yield \ Rate} {Theorical \ Rate} \times 100[/tex]

[tex]47\% = \frac{Actual \ yield \ Rate}{4860}[/tex]

The value of the Actual yield Rate =[tex]47\% \times 4860[/tex]

                                                        [tex]= \frac{47}{100} \times 4860 \\\\ = 2284.2 g[/tex]

The Actual yield Rate= 2284.2 g.

Answer:

1: exothermic

2:hydrated iron (III) oxide

3:reactants

4:precipitate

5: hydrogen gas

Answer:1.exothermic

2.hydrated iron (III) oxide

3.reactants

4.precipitate

5. hydrogen gas

Answer:

The answer is D. Hydrochloric acid solution with a pH of 1.

Explanation:

I just took the same quiz

Hydrochloric acid solution with a pH of 1. Hence, option D is correct.

An acid is an electrolyte that hydrolyses in water to release hydrogen ions.

The lower the pH the greater the concentration of H+ ions. Hydrochloric acid with a pH of 1 is a strong acid and is highly ionised in solution.  It has the most H+ ions.

Hence, option D is correct.

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The correct answer is D. The native species would not have to  compete for necessary resources

Explanation:

Invasive species, which include any living organism that is not native in an ecosystem, contribute to the extinction of native species as they compete for resources such as food, shelter, etc. with native species. For example, the  Asian Carp, which was introduced to lakes in the U.S. consumes plankton, which reduces the amount of plankton available for native fish. In this context, by removing invasive species native species would not have to compete for resources and their chances to extinct will fall.

Answer:

%m/v =70%

Explanation:

El %m/v es una unidad de concentración que se define como cien veces la división entre la masa de una sustancia (En gramos) y el volumen total en el que esta sustancia se encuentra (en mL).

En el problema, debemos hallar la masa de etanol (Alcohol) y el volumen total de la solución.

Masa alcohol:

Ya te la dan en el problema: 105g

Volumen solución:

Volumen agua: 15mL

Volumen etanol: 105g × (1mL / 0.798g) = 131mL

Volumen Jabón líquido: 4.5g × (1mL / 1.5g) = 3mL

Volumen: 15mL + 131mL + 3mL

149mL

Así, el %m/v de alcohol en la solución es:

%m/v = (105g / 149mL) × 100

Answer:

[tex]7.589\times 10^{2}[/tex]

Explanation:

The expression can be solved mathematically as follows:

1) [tex]8.310\times 10^{2}-7.210\times 10^{1}[/tex] Given

2) [tex]8.310\times 10^{1+1} - 7.210\times 10^{1}[/tex] Definition of sum

3) [tex](8.310\times 10^{1})\times 10^{1}-7.210\times 10^{1}[/tex] [tex]a^{m+n} = a^{m}\cdot a^{n}[/tex]/Associative property

4) [tex](8.310\times 10^{1}-7.210)\times 10^{1}[/tex] Distributive property

5) [tex](83.100-7.210)\times 10^{1}[/tex] Multiplication

6) [tex]75.89\times 10^{1}[/tex] Subtraction.

7) [tex](7.589\times 10^{1})\times 10^{1}[/tex] Multiplication/Associative property

8) [tex]7.589\times (10^{1}\times 10^{1})[/tex] Associative property

9) [tex]7.589\times 10^{2}[/tex] [tex]a^{m+n} = a^{m}\cdot a^{n}[/tex]/Result

Answer:

Producer gas and water gas contain carbon monoxide and hydrogen.

Answer:

Virus is living due to reproduction and non-living due to crystal appearance.

Explanation:

Characteristics that viruses display is the ability of reproduction in which they increase in population which is a living character and have DNA or RNA which help them to make exact copies of itself. Virus is parasitic in nature because it causes harm to the living host such as humans, animals and plants. Some characteristics that viruses don't display are that they are not like living cells, have no membrane around them, no organelles such as mitochondria, golgi bodies, endoplasmic reticulum and lysosomes etc. Viruses are present in crystal form outside the cell.

Answer:

Yes, it is possible. Let us consider an example of two solutions, that is, solution A having 20 percent mass RbCl (rubidium chloride) and solution B is having 15 percent by mass NaCl or sodium chloride.  

It is found that solution A is having more concentration in comparison to solution B in terms of mass percent. The formula for mass percent is,  

% by mass = mass of solute/mass of solution * 100

Now the formula for molality is,  

Molality = weight of solute/molecular weight of solute * 1000/ weight of solvent in grams

Now molality of solution A is,  

m = 20/121 * 1000/80 (molecular weight of RbCl is 121 grams per mole)

m = 2.07

Now the molality of solution B is,  

m = 15/58.5 * 1000/85

m = 3.02

Therefore, in terms of molality, the solution B is having greater concentration (3.02) in comparison to solution A (2.07).

Explanation:

SOLID

Sodium hydroxide exists in the solid phase at room temperature. You would find it in the lab as hemispherical white solid pellets. The phase of a substance depends on temperature and pressure. As you heat a solid, it will melt and change to the liquid phase.

Answer:

Total gram of Ca = 99.26 g

Explanation:

Given:

Mass of CaCl₂ = 277.45 g

Find:

Mass of Ca

Computation:

Ca = 40 g/mol

Cl₂ = 2 (35.5) g/mol = 71 g/mol

Total CaCl₂ = 111 g/mol

Total gram of Ca = [40 / 111] 277.45 g

Total gram of Ca = 99.26 g

Answer:

2N2 + 5O2 => 2N2O5

4Fe + 3O2 => 2 Fe2O3

H2 + Cl2 => 2 HCl

Answer:

B.They do not react chemically

Explanation:

This is because all noble gases haves full outer shell therefore they don’t participate in bonding.They are referred to as inert which means unreactive.

Answer:

They do not react chemically

Explanation:

Answer:

The pH of the solution following the addition of 0.075 moles of NaOH is 5.7.

Explanation:

The equation of the buffer solution is the following:

C₄H₇O₂H(aq) + H₂O(l) ⇄ C₄H₇O₂⁻(aq) + H₃O⁺(aq)     (1)    

The pH of the buffer solution can be found using the Henderson-Hasselbalch equation:

[tex] pH = pKa + log(\frac{[NaC_{4}H_{7}O_{2}]}{[C_{4}H_{8}O_{2}]}) [/tex]   (2)

The NaOH added will react with butanoic acid tot produce sodium butanoate:

C₄H₇O₂H(aq) + OH⁻(aq) ⇄ C₄H₇O₂⁻(aq) + H₂O(l)  (3)          

[tex] n_{C_{4}H_{7}O_{2}H}_{i} = C*V = 0.107 M*1.30 L = 0.139 moles [/tex]

[tex] n_{C_{4}H_{7}O_{2}^{-}} = 0.345 M*1.30 L = 0.449 moles [/tex]

[tex] n_{NaOH} = 0.075 moles [/tex]

[tex] n_{C_{4}H_{7}O_{2}H} = 0.139 moles - 0.075 moles = 0.064 moles [/tex]

[tex] n_{C_{4}H_{7}O_{2}^{-}} = 0.449 moles + 0.075 moles = 0.524 moles [/tex]

[tex]C_{C_{4}H_{7}O_{2}H} = \frac{0.064 moles}{1.30 L} = 0.049 M[/tex]

[tex] C_{C_{4}H_{7}O_{2}^{-}} = \frac{0.524 moles}{1.30 L} = 0.403 M [/tex]

Now, from equation (1) we have:

C₄H₇O₂H(aq) + H₂O(l) ⇄ C₄H₇O₂⁻(aq) + H₃O⁺(aq)

0.049 - x                           0.403 + x            x  

[tex] Ka = \frac{[C_{4}H_{7}O_{2}^{-}][H_{3}O^{+}]}{C_{4}H_{7}O_{2}H} [/tex]

[tex]1.52 \cdot 10^{-5} = \frac{(0.403 + x)x}{0.049 - x}[/tex]

[tex]1.52 \cdot 10^{-5}*(0.049 - x) - (0.403 + x)x = 0[/tex]

By solving the above equation for x we have:            

x = 1.85x10⁻⁶ = [H₃O⁺]

So, the concentration of butanoic acid and sodium butanoate is:

[tex][C_{4}H_{7}O_{2}^{-}] = 0.345 + 1.85 \cdot 10^{-6} = 0.345 M[/tex]

[tex][C_{4}H_{7}O_{2}H] = 0.049 - 1.85 \cdot 10^{-6} = 0.049 M[/tex]

Finally, from equation (2) we have:

[tex] pH = pKa + log(\frac{[NaC_{4}H_{7}O_{2}]}{[C_{4}H_{8}O_{2}]}) [/tex]

[tex]pH = -log(1.52 \cdot 10^{-5}) + log(\frac{0.345}{0.049}) = 5.7[/tex]

Therefore, the pH of the solution following the addition of 0.075 moles of NaOH is 5.7.

I hope it helps you!

Answer:

-A molecule is the smallesr part is compound whereas a compound is the combination of two or more atoms in a fixed proportion by wiehgt.

- A glass of water is an example of compound but a small portion of water can be called molecule.

Answer:

The answer is

555.94g

Explanation:

To find the mass of a substance given it's density and volume we use the formula

Making mass the subject we have

mass = Density × volume

From the question

Density = 7.7 g/cm³

Volume = 72.2 cm³

Substitute the values into the above formula

That's

mass = 7.7 g/cm³ × 72.2 cm³

We have the final answer as

Hope this helps you

Answer:

The answer is Neon

Answer:

neon

Explanation:

neon has a complete outer 2n shell

Answer:

I believe it's A) an array of positive ions in a sea of electrons

Answer:

The average mass of the gold coin reported to five significant figures, even though you  had to divide by "3" to obtain the average.

Explanation:

Given that,

The mass of a silver liberty was measured three times and each measurement was made  to five digits.

The mass values are,

[tex]m_{1}=12.519\ g[/tex]

[tex]m_{2}=12.521\ g[/tex]

[tex]m_{3}=12.496\ g[/tex]

The average mass of the gold  coin is 12.512 g.

We know that,

Significant figures :

Significant figures is explained the nonzero, leading zero and zeros between two nonzero digits.

For example,

The digits is 0.003405

In the digit, 345 = nonzero

0.00 = leading zero

The average mass of the gold coin reported to five significant figures because average mass is 12,512. All digits are nonzero.

Nonzero digit are significant.

Hence, The average mass of the gold coin reported to five significant figures, even though you  had to divide by "3" to obtain the average.

Answer:

Explanation:

given mass on earth =98 kg

gravitational pull on mars =3.711 m/s2

gravitational pull on venus =8.87 m/s2

weight of the body on mars =weight on earth/9.81 m/s2 *3.711 m/s2

W=98 kg*3.711 /9.81m/s2

W=37.07 kg

weight on the venus =weight on earth*8.87 m/s2 /9.81 m/s2

W= 98 kg*7.87 m/s2/9.81 m/s2

W=78.62 kg