A neutral isotope has 45 neutrons and 36 electrons. Identify the element symbol of this isotope and determine the mass number and number of protons. element symbol: mass number: number of protons:

Answer:

The correct answer is 0.10.

Explanation:

Based on the given question, in a buffer solution of 1 liter, the molarity of acetic acid is 1.420 M and the molarity of sodium acetate is 0.67. The pKa value of acetic acid given is 4.74, now the pH of buffer is,  

pH of buffer = pKa + log ([CH3COONa]/[CH3COOH])

= 4.74 + log (0.67/1.420)

= 4.74 + (-0.326)

= 4.41  

Now 0.10100 mol of HCl is added, the HCl reacts with sodium acetate to give,  

CH3COONa + HCl = CH3COOH + NaCl

Now the concentration of CH3COONa becomes = 0.67-0.101 = 0.57 M, and the new concentration of CH3COOH becomes = 1.420 + 0.101 = 1.52 M

Now the new pH will be,  

= pKa + log (0.57/1.52)

= 4.74 + (-0.426)

= 4.31

The pH change is 4.41-4.31 = 0.10  

Answer:

THE STANDARD HEAT OF FORMATION FOR C3H8 IS 9.59 KJ/MOL.

Explanation:

Mass = 5 g of C3H4

Mass of water = 15 kg

Initial temperature of water = 25 C = 25 + 273 K = 298 K

Final temperature of water = 3.688 C = 3.688 + 273 K = 276.688 K

We may make the assumptions that:

1. the specific heat of water = 4.2 J/Kg K

2. total mass of the reaction mixture = 15 kg of water + 5 g of C3H8

= 15.005 Kg

Temperature change = 298 - 276.688 = 21.312 K

heat change for the reaction

Heat = mass * specific heat * change in temperture

Heat = 15.005 * 4.2 * 21.312

Heat = 1343.10 J

EQUATION

C3H8 + 5O2 -> 3CO2 + 4H2O + heat

Number of mole = mass / molar mass

Molar mass of HCl = 36.5 g/mol

Number of mole = 5 g/ 36.5 g/mol

Number of mole = 0.14 moles

5 g of C3H8 produces 1343.10 J of heat

0.14 mole of C3H8 produces 1343.10 J

1 mole of C3H8 will produce 1343.10 / 0.14 J of heat

= 9593.57 J

= 9.59 kJ of heat.

The standard heat of formation for C3H8 is 9.59 kJ/mol.

The characteristics of a strong acid is that it has a weaker bond to hydrogen. That is option D.

A strong acid is defined as the type of acid that completely dissociates in an aqueous solution during a chemical reaction.

Typical examples of strong acid include the following:

The characteristics of strong acids over weak acids is that they bond weakly with hydrogens.

Learn more about acids here:

https://brainly.com/question/27915098

#SPJ6

Answer:

To obtain a desired component from the mixture

Explanation:

It is also important to be able to separate mixtures to be able to better understand how each component contributes to the properties, chemical and physical, of the resulting mixture.

Answer:

The correct answer is 12.6.

Explanation:

The formation of benzoate takes place when potassium hydroxide reacts with benzoic acid, due to the presence of a weak acid and its conjugated base the solution will act as a buffer. In the given question, the molarity of benzoic acid given is 0.8700 M and its volume is 60.5 ml. Therefore, the moles of benzoic acid will be,  

Moles = molarity * volume of solution  

= 0.8700 M * 60.5 ml = 52.365 m mol or 0.052365 moles

On the other hand, the molarity of KOH given is 0.3600 M and the volume given is 172 ml. Therefore, the moles of KOH added will be,  

Moles = 0.3600 * 172 = 61.92 m moles or 0.06192 moles

Out of this 61.92 m mol, only 52.365 m mol of KOH will react with the benzoic acid. The moles of KOH, which remain unreactive is,  

61.92 m moles - 52.365 m moles = 9.285 m moles or 0.009285 moles

The formula for calculating molarity is number of moles / volume of solution in liters

The total volume of the solution is 172 ml + 60.5 ml = 232.5 ml or 0.2325 L

The molarity of KOH will be,  

Molarity = 0.009285 moles / 0.2325 L = 0.0395 M

The dissociation of KOH takes place completely to produce hydroxide ion.  

pOH = -log[0.0395] = 1.4

pH + pOH = 14

pH = 14 - 1.4 = 12.6

Answer:

i have the same question

Explanation:

Answer:

The correct answer is 1.89130 × 10⁻² g per ml.

Explanation:

Based on the given information, the volume of the water sample is 46 ml, the temperature given is 21 degree C. Weight of the compound mineral X is 0.87 grams obtained post evaporating, washing, and drying of the sample. Yes, on the basis of the given information, one can find the solubility of compound X in water at 21 degree C.  

As 46 ml of water comprise 0.87 grams of the mineral compound X. Therefore, 1 ml of the water sample will comprise,  

= 0.87/46 g of X

= 1.89130 × 10⁻² grams

Hence, the solubility of the compound X in the sample of water is 1.89130 × 10⁻² gram per ml.  

Answer:

principle quantum number :)

Explanation:

I took the test and got it right

Quantum numbers are defined as the set of four numbers with the help of which we can get complete information about the electrons in an atom. The energy level of an electron is given by Principal quantum number. The correct option is B.

The Principal quantum number represents the main energy level or shell in which the electron is present. It also determines the average distance of the orbital or electron from the nucleus. It is denoted by the letter 'n' and can have any whole number values like 1, 2, 3, 4,....

The value of principal quantum number usually stand for different energy shells K, L, M, N .... the value of 'n' can be any integer with a positive value which is equal to or greater than 1.

The value of 'n' denotes the innermost electron shell of an atom which indicates the lowest energy state of an electron. It cannot be a negative value.

Thus the correct option is B.

To know more about Principal quantum number, visit;

https://brainly.com/question/30656222

#SPJ2

Answer:

Lengths. of. Naphthalene. Figure 3.20 shows that there are two equivalent ... all the carbon–carbon bonds of benzene are identical and are intermediate in length ... A typical carbon–carbon single bond has a length of 1.54 Å, and a double ... of how resonance can be used to explain or predict experimental observations.Explanation:

Answer:

HClO₃

Explanation:

Empirical formula of a chemical compound is defined as the simplest ratio of atoms presents in the compound (In whole numbers).

For the H₂Cl₂O₆ the empirical formula could be obtained dividing in 2 the formula. That is:

HClO₃ → This is the simplest ratio of atoms presents in the compound, that is, the empirical formula

Answer:

128

Explanation:

Step 1: Write the balanced equation

H₂(g) + I₂(g) ⇌ 2 HI(g)

Step 2: Make an ICE chart

         H₂(g) + I₂(g) ⇌ 2 HI(g)

I         3.75     2.15         0

C         -x         -x         +2x

E      3.75-x   2.15-x      2x

Step 3: Find the value of x

Since the concentration of I₂ at equilibrium is 0.0800 M,

2.15M-x = 0.0800 M

x = 2.07 M

Step 4: Calculate the concentrations at equilibrium

[H₂] = 3.75-x = 3.75-2.07 = 1.68 M

[I₂] = 0.0800 M

[HI] = 2x = 2(2.07) = 4.14 M

Step 5: Calculate the equilibrium constant Kc

[tex]Kc= \frac{[HI]^{2} }{[H_2]\times [I_2]} = \frac{4.14^{2} }{1.68\times 0.0800} = 128[/tex]

Answer:

A neutralization reaction between an acid and a base will produce a salt and water. In a neutralization reaction, the acid will produce H+ ions that react to neutralize the OH- ions produced by the base, forming neutral water. ... A weak acid + a strong base in an acid/base neutralization reaction will form a basic salt

Explanation:

Answer:

5.33 g

Explanation:

Let's consider the balanced reaction for the complete decomposition of solid sodium bicarbonate to form solid sodium hydroxide and carbon dioxide gas when heated.

NaHCO₃(s) → NaOH(s) + CO₂(g)

According to Lavoisier's law of conservation of mass, the sum of the masses of the reactants is equal to the sum of the masses of the products. Then,

m(NaHCO₃) = m(NaOH) + m(CO₂)

m(CO₂) = m(NaHCO₃) - m(NaOH)

m(CO₂) = 10.17 g - 4.84 g

m(CO₂) = 5.33 g

Answer:

B) chemical energy to electrical energy

Explanation:

The correct option is B.

A voltaic cell is an electrochemical cell that uses a chemical reaction to produce electrical energy. The important parts of a voltaic cell: The anode is an electrode where oxidation occurs. The cathode is an electrode where reduction occurs.

A galvanic cell is an electrochemical cell that converts the free energy of a chemical process into electrical energy. A photogalvanic cell is one that generates species photochemically which react resulting in an electrical current through an external circuit.

Learn more about energy conversion here https://brainly.com/question/961052

#SPJ2

Answer:

0.5472 moles of H₂O are produced

0.1992 moles of C₈H₁₈ were left

Explanation:

The reaction of octane (C₈H₁₈) with oxygen (O₂) is:

C₈H₁₈ + 25/2 O₂ → 8CO₂ + 9H₂O

Where 1 mole of octane reacts with 25/2 moles of oxygen to produce 8 moles of carbon dioxide and 9 moles of water

For a complete reaction of 0.760moles of oxygen there are needed:

0.760 mol O₂ ₓ (1 mole C₈H₁₈ / 25/2 moles O₂) = 0.0608 moles of C₈H₁₈

As you have 0.260 moles, the moles of octane that were left are:

0.260 mol - 0.0608 mol = 0.1992 moles of C₈H₁₈

Now, if 0.760 moles of O₂ react, the moles of water that are produced are:

0.760 mol O₂ ₓ (9 moles H₂O / 25/2 moles O₂) = 0.5472 moles of H₂O

Answer:

Louis-Bernard Guyton De Morveau

Explanation:

He is who proposed the first systematic nomenclature for naming chemical compounds.

Answer:

it is either a or c because they make the most sense

Answer:

Partial pressure of krypton= 167.12 mmHg

Partial pressure of argon = 565.88 mmHg

Explanation:

The partial pressure of a gas in a mixture of gasses is equal to the total pressure multiplied (Pt) by the mole fraction of the gas (X):

P= X Pt

The total pressure is Pt= 733 mmHg

The mole fraction is given by the following:

X = number of moles of gas/ total number of moles

For krypton (Kr) , the molecular weight is 83.8 g/mol and we calculate the number of moles by dividing the mass into the molecular weight as follows:

moles of Kr = 3.97 g/(83.8 g/mol)= 0.047 moles

For argon (Ar), the molesular weight is 39.9 g/mol, so we calculate the number of moles as follows:

moles of Ar = 6.34 g/(39.9 g/mol)= 0.159

Now, we calculate the total number of moles (nt):

nt= moles of Kr + moles of Ar = 0.047 moles + 0.159 moles = 0.206 moles

The mole fraction of each gas is now calculated:

X(Kr)= moles of Kr/nt = 0.047 moles/0.206 = 0.228

X(Ar)= moles of Ar/nt = 0.159 moles/0.206 = 0.772

Finally, with the mole fractions and the total pressure we calculate the partial pressure of each gas as follows:

P(Kr) = X(Kr) x Pt = 0.228 x 733 mmHg= 167.12 mmHg

P(Ar) = X(Ar) x Pt = 0.772 x 733 mmHg= 565.88 mmHg

Answer:

[tex]C_2=9.066x10^{-4}M[/tex]

Explanation:

Hello,

In this case, the first step is to compute the molarity of the first solution, for which we consider the molar mass of iron (III) nitrate that is 241.86 g/mol to compute the moles in 100.00 mL (0.1 L) of solution:

[tex]M=\frac{0.5482g*\frac{1mol}{241.86 g} }{0.1L}=0.0227 M[/tex]

Which is actually the concentration of iron (III) ions. Therefore, for 10.00 mL of such solution, the concentration until a dilution to 250.0 mL results being:

[tex]C_2=\frac{C_1V_1}{V_2} =\frac{0.0227M*10.00mL}{250.0mL} \\\\C_2=9.066x10^{-4}M[/tex]

Best regards.

Answer: spectator ions

Explanation:

A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.

Spectator ions are defined as the ions which does not get involved in a chemical equation or they are ions which are found on both the sides of the chemical reaction present in ionic form.

The total ionic chemical equation is:

[tex]Ag^+(aq)+NO_3^-(aq)+Na^+(aq)+Cl^-(aq)\rightarrow AgCl+Na^+(aq)+NO_3^-(aq)[/tex]

The ions which are present on both the sides of the equation are sodium and nitrate ions which are called as spectator ions and hence are not involved in net ionic equation.

Answer:

D

Explanation:

When Na and Cl react, Na gives up one electron to Cl to fill both their valence electron shells. Both atoms are more stable, chlorine gains the electrons, and chloride is the anion.

Answer: D. After reacting, each ion has a stable octet. (For Gradpoint)

Explanation:

Here is the correct question.

Draw the molecule by placing atoms on the grid and connecting them with bonds. Include all lone pairs of electrons.

NF3

SBr2

CCl4

Answer:

Explanation:

The objective here is to draw the molecule three molecules by placing atoms on the grids and connecting them with their respective bonds, therefore including all the lone pairs of electrons.

See the attachment below for the diagrams.

The first compound is know as Nitrogentrifluoride. A non-flammable greenhouse gas. It is majorly used for he production of semi conductors. It has a trigonal planar structure.

SBr2: Sulfur dibromide is a yellowish liquid toxic gas. It results as a reaction between SCl_2 and HBr. Its has a Bent Structure.

CCl_4 : carbon tetrachloride has the presence of a colourless liquid with a sweet smell. Carbon tetrachloride is used for different domestic uses such as: cleaning surfaces, fumigating, cleaning metals etc. It has a tetrahedral structure.

Answer:

The amount of  ampicillin stock is  [tex]V_3 = 7.5 mL[/tex]

The amount of deionized  is 22.5 \ mL

Explanation:

From the question we are told that

   The volume of stock solution of ampicillin in de-ionized water is [tex]V_0 = 100 mL[/tex]

   The concentration (in mg ) of ampicillin in de-ionized is [tex]C_0 = 100 mg/mL[/tex]

    The volume of ampicillin in deionized water to produce is [tex]V_2 = 30ml[/tex]

The concentration (in mg )  of ampicillin in de-ionized water to produce is [tex]C_2 = 25 mg/mL[/tex]

The chemical process can be mathematically represented as

            [tex]V_3 100 = 30 * 25[/tex]

=>          [tex]V_3 = \frac{30*25}{100}[/tex]

             [tex]V_3 = 7.5 mL[/tex]

The amount of  ampicillin stock is  [tex]V_3 = 7.5 mL[/tex] and amount of 25 mL  (30 - 7.5 = 22.5 mL ) of deionized water

Complete Question

The complete question is shown on the first uploaded image

Answer:

The step wise mechanism  is shown on the second uploaded image

Explanation:

Answer:

1.11 L

Explanation:

Given data

Step 1: Calculate the moles corresponding to 86.9 g of oxalic acid

The molar mass of oxalic acid is 90.03 g/mol.

[tex]86.9g \times \frac{1mol}{90.03g} = 0.965 mol[/tex]

Step 2: Calculate the volume of a 0.871 M solution that contains 0.965 moles of oxalic acid

The molarity is equal to the moles of solute (n) divided by the volume of the solution (V).

[tex]M = \frac{n}{V} \\V = \frac{n}{M} = \frac{0.965mol}{0.871 mol/L} =1.11 L[/tex]

Answer:

2. Muscular System

Explanation:

The muscular system is associated with body motion. Hence, the right answer is option 2.

Answer:

E = 16 J

Explanation:

We have,

You put scruffy can run up to 2 m/s on his fastest days scruffy has a mass of 8 kg

It is required to find the maximum kinetic energy on his fastest days. If v is the velocity, then kinetic energy is given by :

[tex]E=\dfrac{1}{2}mv^2[/tex]

Plugging all the values,

[tex]E=\dfrac{1}{2}\times 8\times 2^2 \\\\E=16\ J[/tex]

So, the maximum kinetic energy on his fastest day is 16 J.

Answer:

Avogadro's number represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units / mole. This number can be used to convert the number of atoms or molecules into number of moles.

1.83 moles K (6.022 x 10^23 atoms / mole ) = 1.10 x 10^24 atoms K

Explanation:

1.83 moles K (6.022 x 10^23 atoms / mole ) = 1.10 x 10^24 atoms

Answer:

the final state of the hydrogen atom = 3

Explanation:

From the given information;

Let first calculate the amount of energy by the ground state atom during the atoms absorbs  photon light  by using the formula:

[tex]E_{absorbs} = \dfrac{hc}{\lambda}[/tex]

where;

h = planck's constant = [tex]6.626*10^{-34 }\ \ Js[/tex]

c = speed of light = [tex]3.0*10^8 \ \ m/s[/tex]

λ = wavelength = 92.57 nm = 92.57 × 10⁻⁹ m

[tex]E_{absorbs} = \dfrac{6.626*10^{-34 }\ \ Js * 3.0*10^8 \ \ m/s}{92.57*10^{-9} \ \ m}[/tex]

[tex]E_{absorbs} = 2.15 *10^{-18} \ J[/tex]

The energy emitted by the hydrogen atom is calculated by using the same formula from above ; but here , the wavelength λ = 954.3 nm = 954.3 × 10⁻⁹ m

[tex]E_{absorbs} = \dfrac{6.626*10^{-34 }\ \ Js * 3.0*10^8 \ \ m/s}{954.3*10^{-9} \ \ m}[/tex]

[tex]E_{absorbs} = 2.08 *10^{-19} \ J[/tex]

The change in the energy absorbed is:

[tex]\Delta E= 2.15 *10^{-18} \ J - 2.08 *10^{-19} \ J[/tex]

[tex]\Delta E= 1.94 *10^{-18} \ J[/tex]

The final state of the atom can be determined by using the relation:

[tex]\Delta E = R_H [\dfrac{1}{1^2}-\dfrac{1}{n^2_f}][/tex]

where;

[tex]R_H[/tex] = Rydberg constant = 2.18 × 10⁻¹⁸ J

[tex]\dfrac{\Delta E}{R_H} = [\dfrac{1}{1^2}-\dfrac{1}{n^2_f}] \\ \\ \\ \dfrac{1.94*10^{-18} \ J}{2.18*10^{-18} \ J } = [\dfrac{1}{1^2}-\dfrac{1}{n^2_f}] \\ \\ \\ 0.889 = [\dfrac{1}{1^2}-\dfrac{1}{n^2_f}] \\ \\ \\ 1 - 0.889 = \dfrac{1}{n^2_f} \\ \\ \\ 0.111= \dfrac{1}{n^2_f} \\ \\ \\ {n^2_f} = \dfrac{1}{0.111} \\ \\ \\ {n^2_f} = 9 \\ \\ \\ {n_f} = \sqrt{9} \\ \\ \\ \mathbf{n_f = 3}[/tex]

Thus; the final state of the hydrogen atom = 3

[tex]E_a_b_s_o_r_b_e_d = (6.626 * 10^-^3^4 J.s) * (3.00 * 10^8 m/s) / (92.57 *10^-^9 m)[/tex]We can use the fact that the energy of the photon is given by the equation: to determine the final position of the hydrogen atom.

E = hc / λ

Where:

E is the energy of the photon,

h is Planck's constant [tex](6.626 * 10^-^3^4 J.s)[/tex],

c is the speed of light in a vacuum [tex](3.00 * 10^8 m/s)[/tex], and

λ is the wavelength of the photon.

Let's first determine the energy of the absorbed photon:

[tex]E_a_b_s_o_r_b_e_d = hc /[/tex]λ[tex]_a_b_s_o_r_b_e_d[/tex]

[tex]E_a_b_s_o_r_b_e_d = (6.626 * 10^-^3^4 J.s) * (3.00 * 10^8 m/s) / (92.57 *10^-^9 m)[/tex]

The energy of the photon released will then be determined by:

[tex]E_e_m_i_t_t_e_d = hc[/tex] / λ[tex]_e_m_i_t_t_e_d[/tex]

E[tex]_e_m_i_t_t_e_d[/tex] = [tex](6.626 * 10^-^3^4 J.s) * (3.00 * 10^8 m/s) / (945.3 *10^-^9 m)[/tex]

The energy difference between the absorbed and released photons must now be determined:

ΔE = [tex]E_e_m_i_t_t_e_d - E_a_b_s_o_r_b_e_d[/tex]

The energy levels of hydrogen are given by the equation:

ΔE = -13.6 eV *[tex](1 / n^2_f_i_n_a_l - 1 / n^2_i_n_i_t_i_a_l)[/tex]

Where

[tex]n_f_i_n_a_l[/tex] and [tex]n_i_n_i_t_i_a_l[/tex] are the principal quantum numbers of the final and initial states, respectively, and -13.6 eV is the ionization energy of hydrogen.

Learn more about energy levels, here:

https://brainly.com/question/30546209

#SPJ6