The fact that a heat pump requires energy to move heat from a colder object (the outside of a house) to a hotter object (the inside of the house) is a real life observation of which thermodynamic law?

Answer:

0.333333 cal/g-°C

Explanation:

Energy = mass x specific heat capacity x temperature change.

(E = mcΔT)

Energy = 100.0 cal

specific heat capacity c= unknown

mass m = 4.0 g

temperature change ΔT = 100 - 25 =75°

100 = 4c(75)

c = 0.333333 cal/g-°C

Answer:

A solute is a solid which dissolves in a solvent. Muddy water contains water and soil, soil does not dissolve in water

Answer:

The metre is defined as the length of the path travelled by light in a vacuum in 1/299 792 458 of a second.

Answer:

36.1%

Explanation:

The following data were obtained from the question:

Mass of hydrated copper sulfate = 2 g

Mass of anhydrous copper sulfate = 1.278 g

Percentage of water =..?

Next, we shall determine the mass of water in the hydrated copper sulfate.

This can be obtained as follow:

Mass of hydrated copper sulfate = 2 g

Mass of anhydrous copper sulfate = 1.278 g

Mass of water =...?

Mass of water = Mass of hydrated copper sulfate – Mass of anhydrous copper sulfate

Mass of water = 2 – 1.278

Mass of water = 0.722 g

Finally, we can obtain the percentage of water in the hydrated copper sulfate as follow:

Mass of water = 0.722 g

Mass of hydrated copper sulfate = 2 g

Percentage of water =..?

Percentage of water = mass of water /mass of hydrate x 100

Percentage of water = 0.722/2 x 100

Percentage of water = 36.1%

Therefore, the percentage of water in the hydrated copper sulfate is 36.1%

Answer:

Niels Bohr, refined the model of an atom by proposing a quantized shell structure atomic model in order to describe how the electrons are able to maintain stable orbits around the nucleus

Based on the predictions of classical mechanics the electron motion of the Rutherford model was unstable as the electrons where expected to have lost some energy during motion and thus having to come rest in the nucleus

According to the modification by Neils Bohr in 1913, electrons move in  shells or orbits of fixed energy and emission of electromagnetic radiation takes place only when electrons changes the orbit in which they move

Explanation:

Answer:

Partial pressure of H₂ = 0.9556 atm

Explanation:

Given:

Barometric pressure = 753 torr

Vapor pressure of water = 26.74 torr

FInd:

Partial pressure of H₂

Computation:

Partial pressure of H₂ = Barometric pressure - Vapor pressure of water

Partial pressure of H₂ = 733 - 26.74  

Partial pressure of H₂ = 726.26 torr

1 atm = 760 torr

So,

Partial pressure of H₂ = 726.26/760

Partial pressure of H₂ = 0.9556 atm

Answer:

Tyndall Effect is the phenomenon of scattering of light by particles in a colloid or in a very fine suspension.

Starch solution would show Tyndall effect.

N/B: Heterogeneous mixtures show Tyndall effect.

Answer:The Tyndall effect is light scattering by particles in a colloid or in a very fine suspension. Also known as Willis–Tyndall scattering, it is similar to Rayleigh scattering, in that the intensity of the scattered light is inversely proportional to the fourth power of the wavelength, so blue light is scattered much more strongly than red light. An example in everyday life is the blue colour sometimes seen in the smoke emitted by motorcycles, in particular two-stroke machines where the burnt engine oil provides these particles.

Under the Tyndall effect, the longer wavelengths are more transmitted while the shorter wavelengths are more diffusely reflected via scattering. The Tyndall effect is seen when light-scattering particulate matter is dispersed in an otherwise light-transmitting medium, when the diameter of an individual particle is the range of roughly between 40 and 900 nm, i.e. somewhat below or near the wavelengths of visible light (400–750 nm).

It is particularly applicable to colloidal mixtures and fine suspensions; for example, the Tyndall effect is used in nephelometers to determine the size and density of particles in aerosols and other colloidal matter (see ultramicroscope and turbidimeter).

It is named after the 19th-century physicist John Tyndall.

Explanation:

Answer:

266 liters Carbon iv oxide will be formed

Explanation:

The first thing we need to do here is to calculate the number of moles of oxygen reacted.

This can be calculated using the ideal gas equation;

Mathematically;

PV = nRT

From the question;

P = pressure = 10.5 atm

V = volume = 400 liters

n = number of moles = ?

T = temperature = 125 + 273 = 398K

R = molar gas constant = 0.0821 L•atm•K^-1•mol^-1

Substituting these values, we have ;

n = PV/RT

n = (10.25 * 400)/(398 * 0.0821) = 125 moles

From the question;

15 moles oxygen gave 10 moles CO2

125 moles oxygen will give x moles CO2

x = (125 * 10)/15 = 83 moles

Now, we want to know the volume of CO2, present in 83 moles using the given reaction conditions.

Mathematically;

PV = nRT

V = nRT/P

= (83 * 0.0821 * 398)/10.25 = 265.65 which is approximately 266 Liters

The question is incomplete, the complete question is;

Atom Number of protons Number of electrons Number of neutrons

1 39 39 52

2 40 40 50

3 39 39 54

4 40 40 51

Based on the information that is given, which atom in the table has the highest mass?

a. 1

b. 2

c. 3

d. 4

Answer:

c

Explanation:

The relative atomic mass is given as; number of protons + number of neutrons. If we take the relative atomic mass of each of the options;

1) 39 +52 = 91

2) 40+50 = 90

3) 39 + 54 = 93

4) 40 + 51 = 91

Thus 3 has the highest mass as seen above, hence the answer given.

Answer:

The solubility of KNO₃ at 40° C is 1 mol/dm³

Explanation:

The solubility of a substance is the number of moles of that substance (solute)  contained in a unit volume of solvent at that particular temperature.

Now, Solubility = n/V where n = number of moles of KNO₃ and V = volume of saturated solution = 50.0 cm³ = 0.05 dm³

n = m/M where m = mass of KNO₃ = 5.05 g and M = molar mass of KNO₃ = 101 g/mol

n = 5.05 g/101 g/mol = 0.05 mol

Solubility = n/V

= 0.05 mol/0.05 dm³

= 1 mol/dm³

So, the solubility of KNO₃ at 40° C is 1 mol/dm³

Answer:

b) 1s22s22p63s23p5

Explanation:

Answer:

b) 1s22s22p63s23p5

Explanation:

edge 2021

Answer:

It has been balanced by using the half-reaction method.

Explanation:

I- and IO3- gives I2

We divide the reaction into two half-reactions

(2 I- >> I2 + 2e-) x5 ( oxidation  : I goes from -1 to 0 )

2 IO3- + 12H+ + 10e- >> I2 + 6H2O ( reduction : I goes from +5 to 0 )

10 I- >> 5I2 + 10e-

2IO3- + 12H+ + 10e- >> I2 + 6H2O

-----------------------------------------------------

10 I- + 2IO3- + 12H+ >> 6I2 + 6H2O

To get the smallest numbers we divide by 2 :

5 I- + IO3- + 6H+ >> 3I2 + 3H2O

It has been balanced by using the half-reaction method. Hence, option B is correct.

A chemical reaction that takes place between an oxidizing substance and a reducing substance.

We divide the reaction into two half-reactions

[tex](2 I^-[/tex] → [tex]I_2 + 2e^-)[/tex] x 5 ( oxidation  : I goes from -1 to 0 )

[tex]2 IO^{3-} + 12H^+ + 10e^-[/tex] → [tex]I_2 + 6H_2O[/tex] ( reduction : I goes from +5 to 0 )

[tex]10 I^-[/tex] →[tex]5I_2 + 10e^-[/tex]

[tex]2IO^{3-} + 12H^+ + 10e^-[/tex] → [tex]I_2 + 6H_2O[/tex]

[tex]10 I^- + 2IO^{3-} + 12H^{+}[/tex]→ [tex]6I_2 + 6H_2O[/tex]

To get the smallest numbers we divide by 2 :

[tex]5 I^- + IO^{3-} + 6H^+[/tex] → [tex]3I_2 + 3H_2O[/tex]

Hence, option B is correct.

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Answer:

La clorofila capta la energía luminosa del sol. (verdadero) La fotosíntesis degrada las sustancias orgánicas que nesecitas las células(falso)

Explanation:

La clorofila es la encargada de dar el pigmento de color verde en las plantas y la que transforma la energia luminica en energia quimica, es por eso que es verdadera.

La fotosintesis NO degrada las sustancias organicas, sino que transforma un sustrato inorganico en una fuente energetica organica para las plantas.

Esto se debe por que las plantas o vegetales son autonomas, es decir que se autoabastecen energeticamente sin necesidad de ingerir alimentos como en el caso de los mamiferos.

Answer:

After the reaction, there will 0.60 g of magnesium oxide and 0.25 g of oxygen gas present in the tube

Explanation:

Equation of the reaction between magnesium and oxygen is given as follows:

2Mg(s) + O₂(g) ---> 2MgO(s)

From the equation of reaction, 2 moles of magnesium reacts with i mole of oxygen gas to produce 1 mole of magnesium oxide

molar mass of magnesium is 24.0 g; molar mass of oxygen gas = 32.0 g; molar mass of magnesium oxide = 40.0 g

Therefore 24 g of magnesium reacts with 32 g of oxygen gas

I.00 g of magnesium will react with (24.0 / 32.0) * 1.00 g of oxygen = 0.75 g of oxygen gas.

Therefore, magnesium is the limiting reagent. Once it is used up, the reaction will stop and the excess oxygen will be left in the tube together with the product, magnesium oxide.

mass of excess oxygen = 1.00 - 0.75 = 0.25 g

mass of magnesium oxide formed = (24.0 / 40.0 g) * 1 = 0.60 g

Answer:

Chemical Changes are also called Chemical Reactions. Chemical reactions involve combining different substances. The chemical reaction produces a new substance with new and different physical and chemical properties. Matter is never destroyed or created in chemical reactions.

Explanation:

Answer:

Atoms consist of a nucleus made of protons and neutrons orbited by electrons.

Isotopes are atoms that have same number of protons but they differ in the number of neutrons and in atomic mass.

Answer:

Isotopes are atoms that have the same numbers of protons but different numbers of neutrons. An ion is an atom that has gained or lost electrons, so it now has more or fewer electrons than it does protons. So an ion has a negative or positive charge.

Hope it helps :)

Answer:

3.125g/mol

Explanation:

To find the molar mass of the gas, we need to initially find the number of moles (n) contained in the gas. To find the number of moles, we use the general gas law whose equation is:

PV=nRT

Where; P= Pressure

V= Volume occupied by gas

n= number of moles

R= general gas constant

(0.0821 L atm mol/K)

T= absolute temperature

According to the question; P= 2.0atm, V= 2.0L, n= ?, T= 298K

To find n, we make it the subject of the formula:

n= PV/RT

n= 2.0 × 2.0 / 0.0821 × 298

n= 4/ 24.4658

n= 0.16mol

If number of moles (n) of the gas is 0.16mol and it weighs 0.500g, its molar mass can be found using:

number of moles (n) = mass (g) / molar mass

Making MM subject of the formula;

molar mass = mass / number of moles

MM= 0.500/0.16

MM= 3.125

Hence, the molar mass of the gas is 3.125g/mol.

Answer:

B) 82 protons

Explanation:

The number of protons for an element never change. 82 Is the atomic number for Pb which is how many protons it has. An isotope means it has more neutrons.

Answer:

The amount of isopropyl alcohol contained in 150 ml of the solution is 117.15 grams

Explanation:

The density of a substance is the mass per unit volume, therefore, we have;

The density of the isopropyl alcohol = 0.785 g/ml at 25°C

The  density = mass/volume

Mass = Density × Volume

The mass of the 150 ml of isopropyl alcohol is therefore;

Mass = 0.785 g/ml × 150 ml = 117.15 g

The amount in grams contained in 150 ml of sample = 117.15 g.

Answer:

–1

Explanation:

The electronic configuration of the neutral atom is given below:

2 8 7

From the electronic configuration of the neutral atom, we can see that the atom has 7 electrons in it's outermost shell. This implies that the element needs 1 more electron to complete it's octet configuration.

Therefore the charge on the ion of the element will be –1 indicating that the atom has received 1 electron to complete it's octet configuration.

Answer:

The correct answer is

Explanation:

hope this helps u!!

Answer:

A meteorologist studies meteorology which is the study of the atmosphere in order to predict/forecast the weather.

Explanation:

I hope this helps.

Answer:

they study the atmosphere and atmospheric events of our weather

Explanation:

Answer:

78.01 g/mol

Explanation:

To find the molar mass of Al(OH)₃, we have to look at the mass of each individual element on the periodic table.

Al - 26.98

O - 3(16.00) = 48.00

H - 3(1.01) = 3.03

Now add it all together.

26.98 + 48.00 + 3.03 = 78.01 or 78 g/mol

Hope that helps.

Answer:

neutrons :

Explanation:

Protons are positively charged, while electrons are negatively charged. Neutrons are electrically neutral, as the name suggests. The electric charge, noted Q , is a physical quantity.

Answer:

(b)

Explanation:

The 3s^2, 3p^6  orbitals form  -3 charge.

This is the element phosphorous and an example of a -3 ion is in aluminium phosphide, AlP3.

The electronic configuration which represents the element forming a simple ion having with a charge of -3 is; 1s², 2s², 2p⁶, 3s², 3p³. Option B is correct.

In this electronic configuration, the element has a total of 16 electrons. To form a simple ion with a charge of -3, the element needs to gain three electrons. This is achieved by adding three extra electrons to the existing configuration.

When the element gains three electrons, the electron configuration becomes:

1s², 2s², 2p⁶, 3s², 3p⁶

This configuration represents the stable octet configuration, where the element has a complete outer shell with eight electrons. Since the charge is -3, it means the element has gained three extra electrons to achieve a stable configuration.

Therefore, the correct electronic configuration representing the element that forms a simple ion with a charge of -3 is 1s², 2s², 2p⁶, 3s², 3p³

Hence, B. is the correct option.

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Answer:

10.2 L of CO₂

Explanation:

Our reaction is:

2C + O₂  →  2CO₂

We convert the mass of C, to moles:

5.50 g / 12g/mol = 0.458 moles

Ratio is 2:2, so if 2 moles of C can produce 2 moles of CO₂ then 0.458 moles of C would produce 0.458 moles of gas.

By the Ideal Gases Law, we know that 1 mol of gas is contained in 22.4L, so:

0.458 mol . 22.4L / 1mol = 10.2 L

Answer:

Transition metals (Group C) have different numbers of valence electrons compared to the other groups mentioned. Therefore option C is correct.

Transition metals (Group 3-12) have varying numbers of valence electrons. This is because their valence electrons are located in more than one energy level or subshell.

The number of valence electrons for transition metals can range from 1 to 12, depending on the specific element within the group. The varying numbers of valence electrons in transition metals contribute to their diverse chemical properties and ability to form multiple oxidation states.

Therefore, transition metals (Group C) have different numbers of valence electrons compared to the other groups mentioned.

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Answer: 22.5 percent of incoming solar radiation goes directly to the surface of the Earth and is absorbed.

Explanation: Transfer of radiation through a planet's atmosphere. A planet and its atmosphere, in our solar system, can radiate back to space only as much energy as it absorbs from incoming solar radiation.

Answer:

Explanation:

I have the notes

"Only about 40 percent actually reaches the surface of the earth"

"our atmosphere and clouds reflect bout 40 percent of incoming solar radiation back into outer space"

"The remaining 60 percent is responsible for warming the earth"

"About 20 percent of this radiation is absorbed directly by the atmosphere"

Answer:

because water gas has high heat content more than producer gas

Explanation:

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