what element has 20 protons 25 neutrons and 20 electrons

Answer:

C. The reaction rate at known reaction concentrations

Explanation:

The rate of a reaction is the measure of the speed of a chemical reaction. To find the rate constant of a reaction, the concentration of the reactants must be known.

Answer:

C. ApE x Approved

Explanation:

Trust

1 is true

2 is d 7

3 is

            1             e

            2             b

            3             d

            4             a

            5             c

1.Sodium metal reacts rapidly with water to form a colorless solution of sodium hydroxide ... strip is placed in a test tube containing 5 mL of hydrochloric acid, HCl. Both liquids ... If it fizzes and bubbles

2.When salt is mixed with water, the salt dissolves because the covalent bonds of water are stronger than the ionic bonds in the salt molecules.

3.When platinum is heated, then cooled to its original state, we say this is a physical change. 19. ... Scratches glass. Sour taste ... A bar of lead is more easily bent than is a bar of aluminum of the same size.

Answer:

6.56×10¹⁴ Hz

Explanation:

From the question given above, the following data were obtained:

Wavelength = 457 nm

Frequency =?

Next, we shall convert 457 nm to metre (m). This can be obtained as follow:

1 nm = 1×10¯⁹ m

Therefore,

457 nm = 457 nm × 1×10¯⁹ m / 1 nm

457 nm = 4.57×10¯⁷ m

Thus, 457 nm is equivalent to 4.57×10¯⁷ m

Finally, we shall determine the frequency of the blue light as follow:

Wavelength = 4.57×10¯⁷ m

Velocity of light = 3×10⁸ m/s

Frequency =?

Velocity = wavelength x frequency

3×10⁸ = 4.57×10¯⁷ × frequency

Divide both side by 4.57×10¯⁷

frequency = 3×10⁸ / 4.57×10¯⁷

frequency = 6.56×10¹⁴ Hz

Therefore, the frequency of the blue light is 6.56×10¹⁴ Hz

Answer: equivalence point

When equal moles of an acid and a base are mixed, after reaction the two are compounds are said to be at the equivalence point.

The equivalence point is called the moment when the equivalents of the titrated substance and those of the titrant substance are equal.

When a strong acid is neutralized with a strong base, the pH undergoes a sharp change just at the equivalence point.

At the time of neutralization, it is true that the number of equivalents of acid that have reacted is equal to the number of equivalents of the base.

This equivalence point is very easily detected since a sharp pH jump is observed in its vicinity, which can be detected in a pH meter or with an indicator.

Therefore, we can conclude that the equivalence point of a reaction is the point at which an equivalent amount of acid and base has been added.

Learn more here: https://brainly.com/question/9297714

Answer:

4Fe + 6H2O + 3O2 -------> 4Fe(OH)3

Explanation:

The chemical reaction involves the fewest oxygen atoms is 4Fe + 6H2O + 302 4Fe(OH)3. Therefore, option B is correct.

The chemical reaction, the transformation of one or more chemicals (the reactants) into one or more distinct compounds (the products). Chemical elements or chemical compounds make up substances.

When atoms establish or break chemical bonds, chemical processes take place. Reactants are the substances that begin a chemical reaction, while products are the compounds that are created as a result of the reaction.

We can learn about a substance's qualities by studying chemical reactions. We can learn about a substance's chemical characteristics by looking at how it interacts with other substances. These characteristics can be utilized to recognize an unidentified sample.

Thus, option B is correct.

To learn more about chemical reaction, follow the link;

https://brainly.com/question/3461108

#SPJ2

Explanation:

Given parameters:

Density of the ethanol  = 0.789g/mL

Volume of the ethanol in the cylinder = 900mL

Unknown:

Mass of the ethanol  = ?

Solution:

Since density is the mass per unit volume of a substance;

      mass  = density x volume

Now insert the parameters and solve;

   mass  = 0.789g/mL x 900mL

   mass  = 710g

In scientific notation we have 7.10 x 10²g

Answer:

Strontium (Sr)

Explanation:

Atomic number 38

Relative atomic mass 87.62

Answer:

The correct is the letter B

Answer: The [tex]K_b[/tex] for the weak base is [tex]3.5\times 10^{-3}[/tex]

Explanation:

[tex]A^-+H_2O\rightarrow HA+OH^-[/tex]

cM                   0          0

[tex]c-c\alpha[/tex]           [tex]c\alpha[/tex]       [tex]c\alpha[/tex] 

So dissociation constant will be:

[tex]K_b=\frac{[HA][OH^-]}{[A^-]}[/tex]

[tex]K_b=\frac{(c\alpha)^{2}}{c-c\alpha}[/tex]

Given :

c= 0.0910 M and pH = 10.50

pOH = 14-pH = 14-10.50 = 3.5

Also [tex]pOH=-log[OH^-][/tex]

[tex][OH^-]=antilog(-3.5)= 3.2\times 10^{-4}M[/tex]

[tex][OH^-]=c\alpha=3.2\times 10^{-4}[/tex]

[tex]K_b=\frac{(3.2\times 10^{-4})^2}{(0.0910-3.2\times 10^{-4}}[/tex]

[tex]K_b=\frac{(3.2\times 10^{-4})^2}{(0.09068}[/tex]

[tex]K_b=3.5\times 10^{-3}[/tex]

Thus [tex]K_b[/tex] for the weak base is [tex]3.5\times 10^{-3}[/tex]

The Kb for the unknown weak base is 3.5 × 10⁻³.

Dissociation constant for a weak base at equilibrium is the ratio of the product of concentration of product to the concentration of un-ionized base.

Chemical reaction for a weak base at initial and equilibrium state can be represented as follow:

[tex]\[\mathop {{{\rm{A}}^{\rm{ - }}}}\limits_{\scriptstyle{\rm{c}}\hfill\atop\scriptstyle{\rm{c - c\alpha }}\hfill} {\rm{ + }}{{\rm{H}}_{\rm{2}}}{\rm{O}}\mathop { \to {\rm{HA}}}\limits_{\scriptstyle{\rm{0}}\hfill\atop\scriptstyle{\rm{c\alpha }}\hfill} {\rm{ + }}\mathop {{\rm{O}}{{\rm{H}}^{\rm{ - }}}}\limits_{\scriptstyle{\rm{0}}\hfill\atop\scriptstyle{\rm{c\alpha }}\hfill} \][/tex]

Kb = [HA] [OH⁻] / [A⁻]

Kb = (c∝)² / (c - c∝)

In the question given that,

pH = 10.50

Concentration of weak base c = 0.0910 M

We know that, pOH = 14 - pH

pOH = 14 - 10.50 = 3.5

Also we now that,

pOH = -log[OH⁻]

[OH⁻] = c∝ = antilog (-3.5) = 3.2 × 10⁻⁴ M

Now we put all these values in the above equation of Kb, we get

Kb = (3.2 × 10⁻⁴)² / (0.0910 - 3.2 × 10⁻⁴) = 3.5 × 10⁻³

Hence, 3.5 × 10⁻³ is the value of Kb.

To know more about dissociation constant, visit the below link:

https://brainly.com/question/3006391

Answer:

4

General Formulas and Concepts:

Chemistry

Explanation:

Step 1: Define

Al₂(SO₃)₃ - Aluminum Sulfide

2Al₂(SO₃)₃

Step 2: Identify

In Aluminum Sulfide, we have 2 Al's for every 3 SO₃²⁻'s.

So far, we have 2 Al's in total.

BUT, since we have a 2 coefficient in 2Al₂(SO₃)₃, we need to multiply by 2.

Therefore, we have 4 Al's in total.

Electronic configuration of carbon at excited state is 1s₂, 2s₂, 2p₂. so, option A is correct.

What is electronic configuration ?

According to electronic configurations, each electron moves individually within an orbital while being surrounded by an average field produced by all other orbitals.

Electronic configuration includes the number of shell, orbit, orbital. s, p, d, f different shell present in it.

One orbital can house a maximum of two electrons, and there are four different types of orbitals (s, p, d, and f). More electrons can be held in the p, d, and f orbitals since they contain various sublevels.

As was said, each element's position on the periodic table determines the specific electron configuration of that element.

Thus, option A is correct.

To learn more about electronic configuration follow the link below;

https://brainly.com/question/14283892

#SPJ6

Answer:

B. habitat

Explanation:

got it right on my test hope this helps:)

Answer:

It's habitat.

Explanation:

I took the Module 3 Exam and got it right.

The average atomic mass of the element, Uk is 67.44 amu.

The average atomic mass of the element Uk is determined from the sum of the isotopic masses of the isotopes of the element and their relative abundances.

The isotopic masses and relative abundance of the isotopes are given below:

Isotope:Uk-66; Isotopic mass = 65.994; relative abundance = 58.00%

Isotope:Uk-69; Isotopic mass = 68.958; relative abundance = ?

Isotope:Uk-71; Isotopic mass = 70.975; relative abundance = 10.00%

Relative abundance of Uk-69 = 100% - (58 + 10)% = 32%

The average atomic mass of Uk =  (65.994 * 58.00%) + (68.958 * 32%) + (70.975 * 10.00%)

The average atomic mass of Uk = 67.44 amu

In conclusion,  the average atomic mass of an element is obtained from the of the isotopic masses of the isotopes of the element and their relative abundances.

Learn more about average atomic mass at: https://brainly.com/question/23093395

#SPJ1

Answer:

yh thats true lol, ty for that very interesting fact

If the pH is higher the concentration of hydrogen ions becomes less and the solution becomes less acidic.

As the pH becomes lower, the concentration of hydrogen ions becomes greater, and the solution becomes more acidic.

HOPE IT'S HELPFUL : )

Answer:

V ≈ 646.50 L

General Formulas and Concepts:

Chemistry - Gas Laws

Explanation:

Step 1: Define

RxN:   N₂H₄ (g) + O₂ (g) → N₂ (g) + 2H₂O (l)

Given:   34.9 °C, 755.08 torr, 914.894 g H₂O

Step 2: Identify Conversions

Kelvin Conversion

Molar Mass of H - 1.01 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of H₂O - 2(1.01) + 16.00 = 18.02 g/mol

Step 3: Convert

Stoichiometry:   [tex]914.894 \ g \ H_2O(\frac{1 \ mol \ H_2O}{18.02 \ g \ H_2O} )(\frac{1 \ mol \ N_2}{2 \ mol \ H_2O} )[/tex] = 25.3955 mol N₂

Temperature:    34.9 + 273.15 = 308.05 K

Step 4: Find Volume

Step 5: Check

We are given 5 sig figs as our lowest. Follow sig fig rules and round.

646.502 L ≈ 646.50 L

Answer: the weight loss of zinc per hour is 6.1 g/h

Option c) 6.1 g/h is the correct answer.

Explanation:

Given that

copper cathode area is =  100 cm²

zinc anode area = 1 cm²

current density at the copper cathode = 0.05 A/cm²

The corrosion current can be converted to a rate of metal loss from its surface by using Faraday's law

W = ItM / nF

W is weight loss of metal , I is current ,

I = iCu × ACu = 0.05 A/cm² x 100 cm² = 5.0 A

M is atomic weight of metal

Atomic mass of Zn = 65.38 g/mol

n = number of electron

F = Faraday’s constant = 96,500 C/mol

so we substitute

W loss of Zn = (5 A) × (3600/h) (65.38 g/mol) / [2 × (96,500 C/mol) ]

= 1176840 / 193000

= 6.098 ≈ 6.1 g/h

Therefore the weight loss of zinc per hour is 6.1 g/h

Option c) 6.1 g/h is the correct answer.

The exclusion zone restricts access to the area around Chernobyl. The soil is still radioactively contaminated after the Chernobyl nuclear explosion. Chernobyl had four nuclear reactors. Uranium dioxide, UO2, was the fuel in the reactors in Chernobyl.

Control rods slow chemical reactions because they absorb neutrons. This prevents the neutrons from reacting with additional uranium Protons and neutrons are found in the nucleus of an atom.

Isotopes are atoms of the same element that have the same number of protons and electrons but different numbers of neutrons. Iodine -131 half-life of eight days, strontium – 90 half-life of 29 years, cesium-137 half-life of 30 years In fission, the nucleus of a Uranium dioxide U-235 atom is bombarded by a neutron.

This splits the nucleus to release a daughter nuclei, more neutrons, and energy. If we start with a 30 g sample of Uranium dioxide I-131, there would be 7.5 grams of I-131.be after 16 days When one atom of uranium goes through fission, the reaction releases a small amount of energy. When the reaction is repeated on the mole scale though, the self-sustaining reaction becomes significantly larger, producing exponentially more energy.

To know more about  Uranium dioxide, visit : https://brainly.com/question/28203717

#SPJ9

Answer:

K^+ and NO3-

Explanation:

The correct answer to the question is Option C. K⁺ and NO₃¯

Spectator ions are ions that remains unchanged in a reaction i.e they can be seen in the reactants and products of a particular reaction.

To obtain the spectator ions in the reaction between KCl (aq) and AgNO₃ (aq), we shall write the ionic equation. This is illustrated below:

KCl (aq) —> K⁺(aq) + Cl¯(aq)

AgNO₃ (aq) —> Ag⁺(aq) + NO₃¯(aq)

KCl (aq) + AgNO₃ (aq) —>

K⁺(aq) + Cl¯(aq) + Ag⁺(aq) + NO₃¯(aq) —> AgCl(s) + K⁺(aq) + NO₃¯(aq)

From the ionic above, we can see that K⁺ and NO₃¯ appears on both side of the equation.

Therefore, K⁺ and NO₃¯ are the spectator ions.

Thus, Option C. K⁺ and NO₃¯ gives the correct answer to the question.

Learn more: https://brainly.com/question/2024427

Answer:

The answer is 2.31×10^12

Explanation:

(4.2×10^9)(5.5×10^2)

(4.2×5.5)×(10^9×10^2)

23.1×10^9+2

23.1×10^11

Answer:2.31×10^12

Answer:runner has a1 and a2 it is heterozygous because it is two different gene verions.

Explanation:

Answer:

The correct answer is 82.18%.

Explanation:

Based on the given information, the mass of the pure soluble bromide compound is 0.4708 grams, and the mass of the formed silver bromide is found to be 0.9093 grams.

The molecular weight of AgBr is 187.77 g/mol, and the molecular weight of Br is 79.9 g/mol.

So, 0.9093 grams of AgBr comprise (79.9 * 0.9093)/187.77 = 0.3869 grams of bromine.

Now, 0.4708 grams of sample comprise 0.3869 grams of bromine. Therefore, 100 grams of sample comprise (0.3869*100) / 0.4708 g = 82.18 grams of bromine.

The mass % of bromine in the original compound is 82.18%.

Answer:

good luckkkkkkkkkkkkkkk

Answer:

Barium chloride + Sodium phosphate    →   barium phosphate + sodium chloride

Explanation:

Double replacement:

It is the reaction in which two compound exchange their ions and form new compounds.

AB + CD → AC +BD

Chemical equation:

BaCl₂ + Na₃PO₄         →     Ba₃(PO₄)₂ + NaCl

Balanced chemical equation:

3BaCl₂ + 2Na₃PO₄         →     Ba₃(PO₄)₂ + 6NaCl

The cation and anion of both reactants are exchanged with each other.

Ba²⁺ react with PO₄³⁻ and form Ba₃(PO₄)₂ while Cl⁻ react with Na⁺ and form sodium chloride.  

Molecular equation:

Barium chloride + Sodium phosphate    →   barium phosphate + sodium chloride

Answer:

Explanation:

The final pressure can be found by using the formula for Boyle's law which is

[tex]P_1V_1 = P_2V_2[/tex]

Since we are finding the new pressure

[tex]P_2 = \frac{P_1V_1}{V_2} \\[/tex]

From the question we have

[tex]P_2 = \frac{25 \times 2}{100} = \frac{50}{100} = \frac{1}{2} \\ [/tex]

We have the final answer as

Hope this helps you

Balanced equation :

3H₂+N₂⇒2NH₃

Equalization of chemical reaction equations can be done using variables. Steps in equalizing the reaction equation:

1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c etc.

2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index between reactant and product

3. Select the coefficient of the substance with the most complex chemical formula equal to 1

Unbalanced⇒the number of atoms from both sides (reactants and products) is not the same

H₂+N₂⇒NH₃

H=2(left), H=3(right)

N=2(left), N=1(right)

Balanced ⇒ the number of atoms from both sides (reactants and products) is equal

3H₂+N₂⇒2NH₃

H=3x2=6(left), H=2x3=6(right)

N=2(left), N=2x1=2(right)