How much energy is needed to heat enough water to make a cup of tea (250 ml), if the water is initially at 20.0°C and you want to increase the temperature to 85.0°C? (1.00 mL of water has a mass of 1.00 g.)

As the tea in the previous question steeps, it cools from 85.0°C to 75.0°C. How much energy is lost by the tea as it steeps?

Answer: EPA regulates the production and distribution of commercial and industrial chemicals, in order to ensure that chemicals for sale and use in the United States do not harm human health or the environment.

Explanation:

Answer:

The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons.

Based on the wave model of light, physicists predicted that increasing light amplitude would increase the kinetic energy of emitted photoelectrons, while increasing the frequency would increase measured current.

La pregunta está incompleta, la pregunta completa es;

"Para enfriar algo rápidamente, haga una mezcla de hielo cd sal o, si

tenga cuidado, alcohol. El punto de congelación bajará y el hielo

derretir rápidamente. A pesar de parecer haber perdido el frío, la mezcla

formado será en realidad unos pocos grados bajo cero y será

mucho más eficaz para enfriar que los cubitos de hielo sólido. "La

fenómeno reportado corresponde a una consecuencia de: *

una. Aumento del punto de ebullición

B. disminución de la presión de vapor

C. aumento de la presión de vapor

D. disminución del punto de congelación

Answer:

D

Explanation:

Esta pregunta recuerda las propiedades coligativas. Las propiedades coligativas son propiedades de sustancias que dependen de la cantidad de sustancia presente.

El punto de congelación es una propiedad coligativa. Se sabe que la presencia de impurezas reduce el punto de fusión y congelación. Esto se llama depresión del punto de congelación.

Por lo tanto, la observación registrada en la pregunta es el resultado de la disminución del punto de congelación.

IMK Your answer is option C

24 protons and 29 neutrons

Answer:

D

Explanation:

Ionic bonds form when a metal and a nonmetal exchange electrons.

A) atoms with relatively similar electronegativities share electrons between them and form covalent bonds

B) the force that holds atoms together in a metallic substance is known as a metallic bond. such a solid consists of closely packed atoms....in short, the valence electrons in metals, unlike those of covalent bonds, are nonlocalized and capable of wandering relatively freely throughout the entire molecule

C) bonds formed between two nonmetals are mainly covalent bonds

.The characteristic that can be written in A only is that ionic bonds are "formed between an atom that tends to lose electrons and an atom that tends to gain electrons" option D.

Ionic or electrovalent bonds are bonds formed between oppositely charged ions which are formed by a gain or loss of electrons and these ions are held together by strong electrostatic forces of attraction.

Therefore, characteristic that can be written in A only is that ionic bonds are "formed between an atom that tends to lose electrons and an atom that tends to gain electrons" option D.

Learn more about ionic bonds at: https://brainly.com/question/13526463

Answer:

pH = 4.27. Porcentaje de disociación: 0.03%

Explanation:

El pH de un ácido débil, HX, se obtiene haciendo uso de su equilibrio:

HX(aq) ⇄ H⁺(aq) + X⁻(aq)

Donde la constante de equilibrio, Ka, es

Ka = 1.65x10⁻⁸ = [H⁺] [X⁻] / [HX]

Como los iones H⁺ y X⁻ vienen del mismo equilibrio podemos decir:

[H⁺] = [X⁻]

[HX] es:

20g * (1mol/55g) = 0.3636moles / 2.100L = 0.1732M

Reemplazando es Ka:

1.65x10⁻⁸ = [H⁺] [H⁺] / [0.1732M]

2.858x10⁻⁹ = [H⁺]²

5.35x10⁻⁵M = [H⁺]

pH = -log[H⁺]

El porcentaje de disociacion es [X⁻] / [HX] inicial * 100

Reemplazando

5.35x10⁻⁵M / 0.1732M * 100

My answer is in the picture.

Stay safe always

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⏩ The scattering of a beam of light through a colloidal solution in its dispersed phase is known as [tex]\large\boxed{tyndall \ \ effect}[/tex].

⁺˚*･༓☾✧.* ☽༓･*˚⁺‧

ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ

꧁❣ ʀᴀɪɴʙᴏᴡˢᵃˡᵗ2²2² ࿐

Answer:

D. Something that splits up light into different colors

Explanation:

A prism separates light into various different colors. Thus, D is correct. :)

Answer: The velocity of the first ball is 0.875 m/s if the second ball travels at 1.5 m/s after collision.

Explanation:

Given: [tex]m_{1}[/tex] = 0.2 kg,      [tex]m_{2}[/tex] = 0.15 kg

[tex]v_{1}[/tex] = 2 m/s,    [tex]v_{2}[/tex] = 0 m/s,      [tex]v'_{1}[/tex] = ?,          [tex]v'_{2}[/tex] = 1.5 m/s

Formula used is as follows.

[tex]m_{1}v_{1} + m_{2}v_{2} = m_{1}v'_{1} + m_{2}v'_{2}[/tex]

where,

v = velocity before collision

v' = velocity after collision

Substitute the values into above formula as follows.

[tex]m_{1}v_{1} + m_{2}v_{2} = m_{1}v'_{1} + m_{2}v'_{2}\\0.2 kg \times 2 m/s + 0.15 kg \times 0 m/s = 0.2 kg \times v'_{1} + 0.15 kg \times 1.5 m/s\\0.4 kg m/s + 0 = 0.2v'_{1} + 0.225 kg m/s\\0.2v'_{1} kg = 0.175 kg m/s\\v'_{1} = \frac{0.175 kg m/s}{0.2 kg}\\= 0.875 m/s[/tex]

Thus, we can conclude that the velocity of the first ball is 0.875 m/s if the second ball travels at 1.5 m/s after collision.

Answer:

Rare earth elements are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium - that appear in low concentrations in the ground.

Explanation:

The rare earth elements (REE) are a set of seventeen metallic elements. These include the fifteen lanthanides on the periodic table plus scandium and yttrium. Rare earth elements are an essential part of many high-tech devices.

Answer:

5 grams of iron react with 5 grams of oxygen to produce iron 3 oxide.

The actual yield of the reaction is--- 5 grams.

What is the percent yield?

Explanation:

The balanced chemical equation of the reaction is:

[tex]4Fe(s)+3O_{2} (g)->2Fe_{2} O_3(s)[/tex]

1)Identify the limiting reagent.

2)Using the limiting reagent calculate the amount of theoretical yield formed.

Identification of limiting reagent:

4 mol of Fe reacts with 3mol. of O2

that is:

4mol(55.84g/mol) of Fe reacts with ---- 3mol (32.0g/mol)

=223.36g of Fe reacts with ---- 96g. of O2

then,

5g of Fe requires how many grams of O2?

[tex]=>5g. of Fe * \frac{96g O2}{223.36g Fe} \\=2.14g. of O_{2} .\\[/tex]

But provided 5g of O2.

So, O2 is present more than required.

Hence, O2 is the excess reagent and the limiting reagent is Fe.

The amount of product formed depends only on the amount of Fe only.

Theoretical yield:

From the balanced chemical equation:

4mol. of Fe forms ----- 2mol. of Fe2O3.

that is

223.36g of Fe forms --- 2(159.68g)of Fe2O3.

=>223.36g of Fe forms --- 319.36g of Fe2O3.

then,

5g of Fe forms ----? grams of Fe2O3

[tex]=>5g of Fe * \frac{319.36g Fe2O3}{223.36g of Fe} \\=7.14g. of Fe2O3\\[/tex]

[tex]%Error =\frac{actual yield}{theoretical yield} * 100\\\\ %error=\frac{5g}{7.14g} * 100\\ %error =70.0[/tex]% error=actual yield/ theoretical yield  x 100

%error=5g./7.14g  x100

=>%error=70.0

Hence, the answer is 70.0%.

Answer:

It would be B!

Explanation:

Since white fur is a form of camouflage, B would be the correct answer.

Answer:

Ionic compounds are formed from strong electrostatic interactions between ions, which result in higher melting points and electrical conductivity compared to covalent compounds. Covalent compounds have bonds where electrons are shared between atoms.

There are seven oxygen atoms, so the total charge is −2⋅7=−14 . So, two chromium atoms have a total oxidation number of +12 . Since one is not more electronegative than the other, we can divide the number by two to get one chromium's oxidation number. So, a chromium atom here has an oxidation number of +6 .

Hope it helps you I'm from ph❤️

Answer:

HNO3 and NaOH

Explanation:

A neutralization reaction is a reaction that occurs between an acid and a base to form salt and water only.

Neutralization reactions are commonly carried out by method of titration. That is, a measured volume of acid of unknown concentration is made to react with a known volume of standard base solution or vice versa.

Two reactants that could be titrated to obtain sodium nitrate are nitric acid and sodium hydroxide.

The reaction equation is as follows;

HNO3(aq) + NaOH(aq) ----> NaNO3(aq) + H2O

Answer:

Lithium, Magnesium, Zinc

Answer:urenium

Explanation: because his atomic number is 235

Answer:

We know when the no of protons (+ charge) is greater than the no of electrons (- charge), the nucleus pulls the electrons with greater force, hence making the size smaller. Clearly, the cations are smaller than the atoms, this largest atom/ion will be Ca.

K has 19 protons, 19 electrons

K+ has 19 protons, 18 electrons

Ca has 20 protons, 20 electrons

Ca2+ has 20 protons, 18 electrons

Li has 3 protons, 3 electrons

Clearly, the cations are smaller than the atoms, this largest atom/ion will be Ca.

Explanation:

Answer:

what???

Explanation:

what??????????

Answer:c

Explanation: it’s c

Answer:

Methane

Explanation:

Alkanes have the molecular formula of "CnH2n+2" which means for every carbon molecule there are two hydrogens plus two more. For example when there is one Carbon there are four hydrogens, this molecule is known as "Methane"

Answer:

B

Explanation:

hope the picture helps you to understand:)

Answer:

4000mL

Explanation:

Using the combined gas law equation;

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure (atm)

P2 = final pressure (atm)

V1 = initial volume (mL)

V2 = final volume (mL)

T1 = initial temperature (K)

T2 = final temperature (K)

According to the information given in this question:

V1 = 1000mL

T1 = 20K

P1 = 1.0atm

V2 = ?

P2 = 0.5atm

T2 = 40K

Using P1V1/T1 = P2V2/T2

1 × 1000/20 = 0.5 × V2/40

1000/20 = 0.5V2/40

50 = 0.5V2/40

50 × 40 = 0.5V2

2000 = 0.5V2

V2 = 2000/0.5

V2 = 4000mL

Answer:

University of University of South New York Jersey has is a the best in the world the most important most important aspect of aspect of life is life and marriage is in my a lot more of a urban

Answer: Weather currents change wind tempature and there for change the weather of the seasons.

The largest particle, Alpha, has the least penetrative power. Positive charge is carried by alpha particles. Two neutrons and two protons are bound together to form an alpha particle. The helium-4 nucleus was later identified as the alpha particle. Among the three types of radioactive emissions, alpha particles have the most mass. An alpha particle has approximately 8000 times the mass of a beta particle. The penetrative power of an alpha particle is reduced due to its large size.

Beta particles are negative-charged high-energy electrons or positrons. Beta particles have a higher penetrative power than alpha particles due to their smaller size.

Hope this helps and if it does, don't be afraid to give my answer a "Thanks" and maybe a Brainliest if it's correct?  

Answer:

= - 303.975 Joules

Explanation:

Given that:

The volume of the cylinder = 0.003 m^3

Now, to liters:

The volume = 0.003 *1000 L

= 3 L

For an open cylinder, we mean the atmospheric pressure is at standard condition.

Thus, the workdone = -PΔV

= - 1 atm (3 L)

= - 3 L atm

1 L atm to Joules

= 101.325 Joules

Therefore;

=- 3* 101.325 Joules

= - 303.975 Joules

Answer:

Synthetic detergents can be used for washing purposes even when the water is hard, whereas soaps are not suitable for washing with hard water. This is because of the fact that synthetic detergents can lather with hard water. Hence, Synthetic detergents better than soaps.

Synthetic detergents work on both soft and hard water, while soap works only with soft water.

Answer:

The total energy, i.e. sum of kinetic and potential energy, is constant.

i.e. E = KE + PE

Initially, PE = 0 and KE = 1/2 mv^2

At maximum height, velocity=0, thus, KE = 0 and PE = mgh

Since, total energy is constant (KE converts to PE when the ball is rising),

therefore, KE = PE 

or, 1/2 mv^2 = mgh

or, h = v^2 /2g = 13^2 / (2x9.8) = 8.622 m

Hope this helps.