At the midpoint of a titration curve ________. At the midpoint of a titration curve ________. The concentration of a conjugate base is twice that of the concentration of a conjugate acid The pH equals the pKa The ability of the solution to buffer is at its least effective The concentration of a conjugate base is 1/2 that of the concentration of a conjugate acid

Answer:

K = 2.96x10⁻¹⁰

Explanation:

Based on the initial reaction:

N2O4 ⇄ 2NO2; K = 1.5x10³

Using Hess's law, we can multiply this reaction changing K:

3 times this reaction:

3N2O4 ⇄ 6NO2; K = (1.5x10³)³ =3.375x10⁹

The inverse reaction has a K of:

6NO2 ⇄ 3N2O4 K = 1/3.375x10⁹;

The carbons on either side of the double bond are pointed in opposite directions.

Answer:

lead causes vessels to constrict, limiting the space for blood to flow (compare the size of the red circles.) This narrowing increases blood pressure, forcing the heart to work harder.

Answer:

By mimicking calcium and increasing cell stress, lead causes vessels to constrict, limiting the space for blood to flow. This forces the heart to work harder because the narrowing increases blood pressure.

Answer:

En la mejora de la investigación y la medicina.

Explicación:

La aparición del microscopio ha permitido la creación de nuevas áreas de estudio, tanto en la mejora de la investigación como en la medicina. La invención del microscopio nos permite crecer y desarrollarnos en el campo de la investigación y el estudio. Con este microscopio, los científicos pudieron descubrir la estructura de la célula, así como las partículas subatómicas que están presentes dentro del átomo. Gracias a este microscopio, los científicos pudieron crecer y desarrollarse en el campo de la creación de nuevos medicamentos.

Answer:

The correct option is 2.

Explanation:

In a nuclear reaction balanced we have that:

1. The sum of the mass number (A) of the reactants (r) is equal to the sum of the mass number of the products (p) [tex] \Sigma A_{r} = \Sigma A_{p} [/tex]

2. The sum of the atomic number (Z) of the reactants is also equal to the sum of the atomic number of the products [tex]\Sigma Z_{r} = \Sigma A_{p}[/tex]      

So, let's evaluate each option.

1) [tex]^{23}_{11}Na \rightarrow ^{24}_{11}Mg + ^{1}_{1}H[/tex]

The mass number of the reactant is:

[tex]A_{r} = 23 [/tex]

The sum of the mass number of the products is:

[tex] A_{p} = 24 + 1 = 25 [/tex]

This is not the correct option because it does not meet the first condition ([tex] \Sigma A_{r} = \Sigma A_{p}[/tex]).

2) [tex]^{24}_{11}Na \rightarrow ^{24}_{12}Mg + ^{0}_{-1}e[/tex]  

The mass number of the reactant and the products is:

[tex]A_{r} = 24 [/tex]

[tex] A_{p} = 24 + 0 = 24 [/tex]

Now, the atomic number of the reactants and the products are:

[tex]Z_{r} = 11 [/tex]

[tex] Z_{p} = 12 + (-1) = 11 [/tex]      

This nuclear reaction is balanced since it does meet the two conditions for a balanced nuclear equation, ([tex] \Sigma A_{r} = \Sigma A_{p}[/tex] and [tex] \Sigma Z_{r} = \Sigma Z_{p}[/tex]).  

3) [tex]^{24}_{13}Al \rightarrow ^{24}_{12}Mg + ^{0}_{-1}e[/tex]      

The mass number of the reactant and the products is:

[tex]A_{r} = 24 [/tex]

[tex] A_{p} = 24 + 0 = 24 [/tex]

Now, the atomic number of the reactants and the products are:

[tex]Z_{r} = 13 [/tex]

[tex] Z_{p} = 12 + (-1) = 11 [/tex]      

This reaction does not meet the second condition ([tex] \Sigma Z_{r} = \Sigma Z_{p}[/tex]) so this is not a balanced nuclear equation.

4) [tex]^{23}_{12}Mg \rightarrow ^{24}_{12}Mg + ^{1}_{0}n[/tex]

The mass number of the reactant and the products is:

[tex]A_{r} = 23 [/tex]

[tex] A_{p} = 24 + 1 = 25 [/tex]  

This reaction is not a balanced nuclear equation since it does not meet the first condition ([tex] \Sigma A_{r} = \Sigma A_{p}[/tex]).

Therefore, the correct option is 2.

I hope it helps you!

Answer:

The boiling point of heavy water is 101.4C

please mark me brainlest pls

Answer: 101.42 Celsius

Explanation:

The boiling point of heavy water is 101.42 Celsius which is higher than the boiling point of normal water (100 Celsius)due to its higher molar mass

Answer:

a

Explanation:

It's a duh

Answer:

Explanation:

The percentage error of a certain measurement can be found by using the formula

[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\ [/tex]

From the question

actual density = 7.80 g/cm³

error = 7.30 - 7.80 = 0.5

We have

[tex]p(\%) = \frac{0.5}{7.8} \times 100 \\ = 6.410256...[/tex]

We have the final answer as

Hope this helps you

Answer:

pure

Explanation:

because there no additional substance

Answer:

the third one...........

Answer:

wax melting off a candle

Answer:

Ozone layer depletion is the thinning of the ozone layer present in the upper atmosphere. This happens when the chlorine and bromine atoms in the atmosphere come in contact with ozone and destroy the ozone molecules. One chlorine can destroy 100,000 molecules of ozone. It is destroyed more quickly than it is created

Answer:

Ozone depletion, gradual thinning of Earth’s ozone layer in the upper atmosphere caused by the release of chemical compounds containing gaseous chlorine or bromine from industry and other human activities. The thinning is most pronounced in the polar regions, especially over Antarctica. Ozone depletion is a major environmental problem because it increases the amount of ultraviolet (UV) radiation that reaches Earth’s surface, which increases the rate of skin cancer, eye cataracts, and genetic and immune system damage. The Montreal Protocol, ratified in 1987, was the first of several comprehensive international agreements enacted to halt the production and use of ozone-depleting chemicals. As a result of continued international cooperation on this issue, the ozone layer is expected to recover over time.

Answer:

Because iodine is a liquid, it has no melting point. Iodine is not an electrical conductor because each molecule consists of two iodine atoms connected by a covalent bond that cannot be stimulated sufficiently to transmit electrical energy.

Explanation:

brainlist???

Explanation:

Because in an aqueous solution of iodine, iodine atoms are joined to each other by simple covalent bonds. Thus, when excitation occurs, the strength of the covalent bond is too weak to be able to transfer electrons, thus lacking the ability to conduct electricity.

Answer:

hope it help u !!!!

Explanation:

Stoichiometry is the relationship between the relative quantities of substances taking part in a reaction or forming a compound, typically a ratio of whole integers

Answer:

See explanation

Explanation:

The functional group is an atom, group of atoms or bond which is responsible for the chemical reactions of the members of a series of organic compounds.

The chemical properties of various groups of compounds in organic chemistry depends of the concept of functional groups. They help us to classify molecules into families or groups based on a common general molecular formula.

The nature of the functional group determines the overall chemical properties of the molecule such as polarity, water solubility, and so on. Chemical reactions occur only at the functional group.

For instance, for the reaction below, reaction occurs at the functional groups as follows;

CH3COOH + CH3OH -------> CH3COOCH3

Also, during amide formation, reaction occurs between the carbonyl chloride and an amine at the respective functional groups as shown;

CH3COCl + CH3NH2 -----> CH3CONHCH3 + HCl

Answer:

0.0013 moles

Explanation:

moles = volume/ molar volume of gas

=240/24000cm3 (convert dm3 to cm3)

=0.0013

Answer:

816L adicionales para mantener la concentración

Explanation:

Cuánta agua debe adicionar el cuidador para que se mantenga la concentración del desinfectante?

El desinfectante, NaClO, idealmente debe estar en una concentración de:

35.8g / 1000L = 0.0358g/L

Como el velador agregó 65g de desinfectante, la cantidad de agua necesaria es:

65g * (1L / 0.0358g) = 1816L de agua son necesarios

Asumiendo que el velador agregó 1000L, el cuidador debe agregar:

1816L - 1000L =

Answer:

333.3mL

Explanation:

Using the formula as follows:

C1V1 = C2V2

Where;

C1 = initial concentration (M)

C2 = final concentration (M)

V1 = initial volume (mL)

V2 = final volume (mL)

According to the information provided in this question,

C1 = 4.00M

C2 = 1.50M

V1 = 125mL

V2 = ?

Using C1V1 = C2V2

4 × 125 = 1.5 × V2

500 = 1.5V2

V2 = 500/1.5

V2 = 333.3mL

Therefore, the CuSO4 solution needs to be diluted to 333.3mL to make 1.50 M solution.

Answer:

The answer is SiO2

Explanation:

Because nonmetals are those who gain electrons and form ve ions

Answer:

A. 31.0

Explanation:

Remember the formula [tex]Density = \frac{mass}{Volume}[/tex], or [tex]D=\frac{m}{V}[/tex].

The problem tells us that the density is 1.89 g/L, and that the volume is 16.4 L.(Remember that if the units are in some form of liters, it is volume, similar to how if the units are in grams, it is mass.)

Plug in the numbers for density and volume, and you will get:

[tex]1.89=\frac{m}{16.4}[/tex]

Then, multiply both sides by 16.4 to get:

m = 30.996 g ≈ 31.0 g

Hope this helps!

Answer:

H2SO4(aq) + MgO(s) → H2O(l) + MgSO4(aq)

Explanation:

We must recall that the oxides of metals are bases. These metal oxides can react with dilute acids to yield salt and water.

Bearing that in mind, we want to obtain magnesium sulfate from a metal oxide and dilute acid.

In this case we need magnesium oxide and dilute sulphuric acid. The reaction occurs as follows;

H2SO4(aq) + MgO(s) → H2O(l) + MgSO4(aq)

Answer:

dont know, will let uk in 2 mins

Explanation:

Explanation:

hope this helps you to understand:)

Answer:

im not entirely sure what needs to be done but the 2NH3 is the product and the other half is the reactants .

if any elements are added to others it is the reactants

this is a breakdown of a compound because the arrow always indicates the direction of the reaction .

Answer:

Sugar was the solute and water was the solvent.

potassium reacts the most vigorously.

Answer:

20.25 W

Explanation:

Applying,

P = I²R.................... Equation 1

Where P = Power, I = current drawn by the test light, R = Resistance of the test light

From the question,

Given: I = 1.5 A, R = 9.00 Ω

Substitute these values into equation 1

P = (1.5²)(9)

P = 2.25×9

P = 20.25 W

Answer:

B) 0.211 M

Explanation:

Answer:

In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. The distinction between physical and chemical change is not clear cut.

Answer:

The products from the neutralization reaction are barium nitrate and water.  

The balanced chemical equation is

2 [tex]HNO_{3}[/tex] +  1 [tex]Ba(OH)_{2}[/tex]  -->  1 [tex]Ba(NO_3)_{2}[/tex] +  2 [tex]H_{2}O[/tex].