Answer in the correct significant figures: 31.2 x 4.13*

Answer:

Hope it helps!!!

............

In the Lewis structure, the Ca atom donates its two valence electrons to two F atoms.

The bonding in calcium fluoride (CaF₂) involves the transfer of electrons from calcium (Ca) to fluorine (F), resulting in the formation of ionic bonds.

Each F atom gains one electron to achieve a stable electron configuration of eight electrons in its outermost energy level. The electrostatic attraction between the positively charged Ca ion (Ca²⁺) and the negatively charged F ions (F⁻) holds the compound together.

It's important to note that the diagram represents a simplified 2-dimensional representation of the compound's structure. In reality, the compound adopts a three-dimensional crystal lattice structure, with each Ca ion surrounded by eight F ions and each F ion surrounded by four Ca ions.

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Answer:

The answer is "no changes in oxidation number "

Explanation:

Given equation:

[tex]3KOH + H_3PO_4 \longrightarrow K_3PO_4 + 3H_2O[/tex]

Answer:

603000 J

Explanation:

The following data were obtained from the question:

Energy required (Q) =...?

Mass (M) = 10000 g

Specific heat capacity (C) = 2.01 J/g°C

Overheating temperature (T2) = 121°C

Working temperature (T1) = 91°C

Change in temperature (ΔT) =.?

Change in temperature (ΔT) =T2 – T1

Change in temperature (ΔT) = 121 – 91

Change in temperature (ΔT) = 30°C

Finally, we shall determine the energe required to overheat the car as follow:

Q = MCΔT

Q = 10000 × 2.01 × 30

Q = 603000 J

Therefore, 603000 J of energy is required to overheat the car.

Answer:D. Oxygen gas

Explanation: because the experiment showed

Answer:

The shape of a molecule based on the number of electron pairs on the valence shell of its central atom

Explanation:

The improvement of the Sidgwick-Powell theory came to be known as the Valence Shell Electron Pair Repulsion theory (VSEPR). This theory approaches the determination of molecular shape from the perspective of the number of electron pairs on the valence shell of the central atom in the molecule.

Electron pairs on the valence shells of atoms leads to repulsion. Repulsion between two lone pairs is greater than repulsion between a lone pair and a bond pair which is also greater than repulsion between two bond pairs.

Lone pairs cause more repulsion, hence they distort molecules from the ideal shape predicted based on their electron domain geometry.

Answer:

The correct option is;

a. Delocalised electrons

Explanation:

The particles that enable electrical conductivity are the delocalised electrons

The metallic structure consists of identically shaped elements having positive ions that have a resultant alignment, surrounded by a vast array of deloclised electrons, which move freely in the metallic structure such that a metallic part usually has a high electrical conductivity.

Therefore, the freely moving delocalised electron in a metal give them the property of good conductors of electricity.

Answer:

1. The limiting reactant is H2O2.

2. The amount of excess reactant, N2H4 that remain unchanged is 11.15 moles.

3. 1.65 moles of N2.

4. 6.6 moles of H2O.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

N2H4 + 2H2O2 —> N2 + 4H2O

From the balanced equation above,

1 mole of N2H4 reacted with 2 moles of H2O2 to produce 1 mole of N2 and 4 moles of H2O.

1. Determination of the limiting reactant.

From the balanced equation above,

1 mole of N2H4 reacted with 2 moles of H2O2.

Therefore, 12.8 moles of N2H4 will react with = 12.8 x 2 = 25.6 moles of H2O2.

From the calculations made above, we can see that it will take a higher amount i.e 25.6 moles than what was given i.e 3.3 moles of H2O2 to react completely with 12.8 moles of N2H4.

Therefore, H2O2 is the limiting reactant and N2H4 is the excess reactant.

2. Determination of the excess reactant that remain unchanged.

The excess reactant is N2H4.

First, we shall determine the amount of the excess reactant that reacted. This is illustrated below:

From the balanced equation above,

1 mole of N2H4 reacted with 2 moles of H2O2.

Therefore, Xmol of N2H4 will react with 3.3 moles of H2O2 i.e

Xmol of N2H4 = (1 x 3.3)/2

Xmol of N2H4 = 1.65 moles

Therefore, 1.65 moles of N2H4 reacted.

Now, we shall determine the excess reactant that remain unchanged. This can be obtained as follow:

Amount of N2H4 given = 12.8 moles

Amount of N2H4 that reacted = 1.65 moles.

Amount of N2H4 that remain unchanged =?

Amount of N2H4 that remain unchanged = (Amount of N2H4 given) – (Amount of N2H4 that reacted = 1.65 moles)

Amount of N2H4 that remain unchanged = 12.8 – 1.65

Amount of N2H4 that remain unchanged = 11.15 moles.

3. Determination of the amount of N2 produced.

In this case, the limiting reactant will be used because it will give the maximum yield of N2 as all of it is used up in the reaction.

The limiting reactant is H2O2 and the amount of N2 produced can be obtained as follow:

From the balanced equation above,

2 moles of H2O2 reacted to produce 1 mole of N2.

Therefore, 3.3 moles of H2O2 will react to produce = (3.3 x 1)/2 = 1.65 moles of N2.

Therefore, 1.65 moles of N2 were obtained from the reaction.

4. Determination of the amount of H2O produced.

In this case, the limiting reactant will be used because it will give the maximum yield of H2O as all of it is used up in the reaction.

The limiting reactant is H2O2 and the amount of H2O produced can be obtained as follow:

From the balanced equation above,

2 moles of H2O2 reacted to produce 4 moles of H2O.

Therefore, 3.3 moles of H2O2 will react to produce = (3.3 x 4)/2 = 6.6 moles of H2O.

Therefore, 6.6 moles of H2O were produced from the reaction.

Answer:

Photometer

Explanation:

A photometer (photo comes from the Greek for light) measures the light coming from 140,000 stars in Kepler's stationary field of view. If a planet transits (passes in front of) any star the amount of light from the star is reduced enough so that the photometer senses it and relays the information back to the Kepler team.

Scientific instruments are tools used for researching the universe and natural sciences. A Photometer is sensitive enough to detect a planet transiting a star. Thus, option D is correct.

A Photometer is a device that converts light energy into electrical voltage by the photoelectric effect given by Einstein. It uses Quantum mechanics to convert the energy possessed by the photons and electrons. It follows Ohm's law to convert energy.

It is used to detect the planets transiting stars as they can detect the light energy as it uses the electromagnetic radiation of various wavelengths to convert them by the photodiode, resistor, and a multiplier.

Therefore, option D. a photometer is used to detect the planets in the universe transiting stars.

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Your question is incomplete, but most probably your full question was, What scientific instrument is sensitive enough to detect a planet transiting a star?

Answer:

The noble as structures attained are helium and argon

Explanation:

The electron configuration of chlorine atom is 1s²2s²2p⁶3s²3p⁵

The elecron configuation of hydrogen is 1s¹

The electron configuration of argon atom is 1s²2s²2p⁶3s²3p⁶

The elecron configuation of helium gas is 1s²

Therefore, in the hydrogen chloride molecule the hydrogen and the chlorine each share one electron from the other atom to attain the the stable noble gas structure of helium for hydrogen and argon for chlorine.

Answer:

[tex]\large \boxed{\text{a)188.4 g; b) 98.67 $\, \%$}}[/tex]

Explanation:

We will need a balanced chemical equation with masses and molar masses, so, let's gather all the information in one place.

Mᵣ:                      98.08           392.18

             2Cr + 3H₂SO₄ ⟶ Cr₂(SO₄)₃ + 3H₂

To solve the stoichiometry problem, you must

a) Mass of Cr₂(SO₄)₃

(i) Mass of pure H₂SO₄

[tex]\text{Mass of pure} = \text{165 g impure} \times \dfrac{\text{85.67 g pure} }{\text{100 g impure}} = \text{141.36 g pure}[/tex]

(ii) Moles of H₂SO₄

[tex]\text{Moles of H$_{2}$SO}_{4} = \text{141.36 g H$_{2}$SO}_{4} \times \dfrac{\text{1 mol H$_{2}$SO}_{4}}{\text{98.08 g H$_{2}$SO}_{4}} = \text{1.441 mol H$_{2}$SO}_{4}[/tex]

(iii) Moles of Cr₂(SO₄)₃

The molar ratio is 1 mol Cr₂(SO₄)₃:3 mol H₂SO₄ [tex]\text{Moles of Cr$_{2}$(SO$_{4}$)}_{3} = \text{1.441 mol H$_{2}$SO}_{4} \times \dfrac{\text{1 mol Cr$_{2}$(SO$_{4}$)}_{3}}{\text{3 mol H$_{2}$SO}_{4}} = \text{0.4804 mol Cr$_{2}$(SO$_{4}$)}_{3}[/tex]

(iv) Mass of Cr₂(SO₄)₃ [tex]\text{Mass of Cr$_{2}$(SO$_{4}$)}_{3} = \text{0.4804 mol Cr$_{2}$(SO$_{4}$)}_{3} \times \dfrac{\text{392.18 g Cr$_{2}$(SO$_{4}$)}_{3}}{\text{1 mol Cr$_{2}$(SO$_{4}$)}_{3}} = \textbf{188.4 g Cr$_{2}$(SO$_{4}$)}_{3}\\\text{The mass of Cr$_{2}$(SO$_{4}$)$_{3}$ formed is $\large \boxed{\textbf{188.4 g}}$}[/tex]

b) Percentage yield

It is impossible to get a yield of 485.9 g. I will assume you meant 185.9 g.

[tex]\text{Percentage yield} = \dfrac{\text{Actual yield}}{\text{Theoretical yield}} \times 100 \, \% = \dfrac{\text{185.9 g}}{\text{188.4 g}} \times 100 \, \% = \mathbf{98.67 \, \%}\\\\\text{The percentage yield is $\large \boxed{\mathbf{98.67 \, \%}}$}[/tex]

Answer:

a. the 3 represents the principal energy level

Explanation:

3 is the principal energy level. The p is the sublevel. 4 is the possible occupying electron.

Answer:

Natural dyes, although pure from chemicals, are often times more expensive than chemical dyes.

Answer: natural dyes is dye that it is anything that grow on earth that haven't been possessed and artificial dye mean that it is good for something in your body or something else

Explanation:i search it up

Answer:

0.35 g.

Explanation:

We'll begin by calculating the number of mole of Fe(NO3)3 in 35 mL of 0.250 M Fe(NO3)3 solution.

This is illustrated below:

Molarity of Fe(NO3)3 = 0.250 M

Volume = 35 mL = 35/1000 = 0.035 L

Mole of Fe(NO3)3 =?

Molarity = mole /Volume

0.250 = mole of Fe(NO3)3 / 0.035

Cross multiply

Mole of Fe(NO3)3 = 0.25 x 0.035

Mole of Fe(NO3)3 = 8.75×10¯³ mole

Next, we shall determine the number of mole of KOH in 55 mL of 0.180 M

KOH solution. This is illustrated below:

Molarity of KOH = 0.180 M

Volume = 55 mL = 55/1000 = 0.055 L

Mole of KOH =.?

Molarity = mole /Volume

0.180 = mole of KOH /0.055

Cross multiply

Mole of KOH = 0.180 x 0.055

Mole of KOH = 9.9×10¯³ mole.

Next, we shall write the balanced equation for the reaction. This is given below:

3KOH + Fe(NO3)3 —> Fe(OH)3 + 3KNO3

From the balanced equation above,

3 moles of KOH reacted with 1 mole of Fe(NO3)3 to produce 1 mole of Fe(OH)3.

Next, we shall determine the limiting reactant. This can be obtained as follow:

From the balanced equation above,

3 moles of KOH reacted with 1 mole of Fe(NO3)3.

Therefore, 9.9×10¯³ mole of KOH will react with = (9.9×10¯³ x 1)/3 = 3.3×10¯³ mole of Fe(NO3)3.

From the above illustration, we can see that only 3.3×10¯³ mole out of 8.75×10¯³ mole of Fe(NO3)3 given is needed to react completely with 9.9×10¯³ mole of KOH.

Therefore, KOH is the limiting reactant and Fe(NO3)3 is the excess reactant.

Next, we shall determine the number of mole of Fe(OH)3 produced from the reaction.

In this case, we shall use the limiting reactant because it will give the maximum yield of Fe(OH)3 as all of it is consumed in the reaction.

The limiting reactant is KOH and the mole of Fe(OH)3 produce can be obtained as follow:

From the balanced equation above,

3 moles of KOH reacted to produce 1 mole of Fe(OH)3.

Therefore, 9.9×10¯³ mole of KOH will react to produce = (9.9×10¯³ x 1)/3 = 3.3×10¯³ mole of Fe(OH)3.

Finally, we shall convert 3.3×10¯³ mole of Fe(OH)3 to grams. This can be obtained as follow:

Molar mass of Fe(OH)3 = 56 + 3(16 + 1) = 56 + 3(17) = 107 g/mol

Mole of Fe(OH)3 = 3.3×10¯³ mole

Mass of Fe(OH)3 =?

Mole = mass /Molar mass

3.3×10¯³ = Mass of Fe(OH)3 / 107

Cross multiply

Mass of Fe(OH)3 = 3.3×10¯³ x 107

Mass of Fe(OH)3 = 0.3531 ≈ 0.35 g.

Therefore, 0.35 g of Fe(OH)3 was produced from the reaction.

Answer:

29

Explanation:

Copper is a chemical element with the symbol Cu and atomic number is 29

Explanation:

Answer:

Inverse proportion occurs when one value increases and the other decreases. For example, more workers on a job would reduce the time to complete the task. They are inversely proportional.

Answer:

A

Explanation:

Answer:

Explanation:

The glass (which does not crystallize even though it is accepted) of a window is NOT a mineral, since it is neither a substance of natural origin (although it is manufactured from natural components) nor does it have a defined crystalline structure, that is, the atoms they are not arranged in an orderly and regular way along axes and planes forming flat faces that keep a symmetry.

Remember that a mineral is defined as a solid, inorganic, homogeneous substance, of natural origin, with a crystalline structure and a determined and well-defined chemical composition within narrow margins and that has regular and characteristic physical properties.

Explanation: No, glass is not a mineral. ... Definable chemical composition: SiO2 *Actually, most industrially-produced glass is not pure silica, but having impurities is still a definable chemical composition so this part of the definition is ok. Orderly arrangement of atoms in a lattice: NO.

Answer:

Explanation:

Simple molecules have very small masses. Instead of writing their actual masses in grams or kilograms, we usually use their relative formula masses. These are calculated using the chemical formula and the relative atomic masses of the elements in it.

Relative formula mass

Relative atomic mass has the symbol Ar. The Ar for an element is a measure of the mass of its atoms compared to the mass of carbon-12 atoms. The greater the Ar value, the more mass an element's atoms have. The periodic table shows the Ar value for each element. For example, the Ar for carbon is 12, and the Ar for magnesium is 24. This means that a magnesium atom has twice the mass of a carbon atom.

Calculating relative formula mass

Relative formula mass is given the symbol Mr. To calculate the Mr for a substance:

work out how many atoms of each element there are in the chemical formula

add together the Ar values for all the atoms of each element present

For example, the formula for carbon dioxide is CO2. It consists of one carbon atom (Ar = 12) and two oxygen atoms (Ar = 16):

Mr of CO2 = 12 + 16 + 16 = 44

It could also be calculated this way:

Mr of CO2 = (1 × 12) + (2 × 16) = 12 + 32 = 44

Ar and Mr values are just numbers. They have no units because they are relative masses.

Relative formula masses of ionic compounds

Ionic compounds such as sodium chloride do not exist as molecules. However, their relative formula masses are calculated in the same way. The formulae used are their empirical formulae.

Answer:

1a) .68 moles 1b)4.1E-23 molecules.

2a) .37 moles 2b) 2.27E-23 molecules

Explanation:

1a) CO2 is equal to 44 grams (C→12 grams,O→16 grams[·2]) .30g/44g is .68 moles.

1b) multiply 1A by advogadros number (6.022E-23)

2a) NaCl is 58 grams. 22/58 is .37 moles.

2b) multiply 2A by advogadros number.

you'd answer #3 the same way #1 and #2

The branch of science that deals with chemicals and bonds are called chemistry. The moles are units to calculate the quantity required to use the element.

The correct answer is mentioned below.

According to the question, the moles to the option is as follows:-

[tex]n =\frac{M}{M.M}\\ \\\frac{30}{44} \\\\=0.681\\\\[/tex]

The number of molecules is [tex]0.68 *6022*10^{23} =4.09496*10^{23[/tex].

2. moles of 22 grams of NaCl is

[tex]\frac{22}{44}\\ \\=0.5\\\\[/tex]

Molecules will be [tex]0.5*6.022*10^{23} = 3.011*10^{23}[/tex]

3. moles of 50-gram ammonia

[tex]\frac{50}{17} \\\\2.94\\[/tex]

The number of molecules is [tex]2.94*6.022*10^{23} = 1770*10^{23[/tex]

For more information about the moles, refer to the link:-

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you can determine this by

Explanation:

eam=%abudance×mass+%abudance×mass

eam=19.8%×10.013/100+80.2%×11.009/100

eam=198.2574/100+882.9218/100

eam=1081.1792/100

eam=10.811792

eam=10.812

Answer:

The number of balloons is 948.8.

Explanation:

The number of balloons can be calculated as follows:

[tex] N = \frac{V_{f}}{V_{T}} [/tex]

Where:

[tex]V_{f}[/tex]: is the volume at 1.086 atm

[tex]V_{T}[/tex]: is the balloon volume = 2.414 L  

The volume at 1.086 atm can be found using Boyle's law:

[tex] P_{i}V_{i} = P_{f}V_{f} [/tex]

[tex] V_{f} = \frac{P_{i}V_{i}}{P_{f}} = \frac{169.1 atm*14.71 L}{1.086 atm} = 2290.5 L [/tex]

Now, the number of balloons is:

[tex] N = \frac{V_{f}}{V_{T}} = \frac{2290.5 L}{2.414 L} = 948.8 [/tex]

Therefore, the number of balloons is 948.8.

I hope it helps you!        

Answer:

Lavoiser proposed a theory in charge of writing the combustion correctly, denying the phlogiston.

Lavoiser said that combustion is carried out in a medium where there is oxygen, giving as a product water and carbon dioxide.

This combustion results in the decrease in the volume of the material that burns.

Furthermore lavoiser discovered the importance of oxygen in animal respiration.

Explanation:

Lavoisier argued that if or if the presence of oxygen must be present, it is an irreversible and spontaneous process.

Answer:

Virus is living due to reproduction and non-living due to crystal appearance.

Explanation:

Characteristics that viruses display is the ability of reproduction in which they increase in population which is a living character and have DNA or RNA which help them to make exact copies of itself. Virus is parasitic in nature because it causes harm to the living host such as humans, animals and plants. Some characteristics that viruses don't display are that they are not like living cells, have no membrane around them, no organelles such as mitochondria, golgi bodies, endoplasmic reticulum and lysosomes etc. Viruses are present in crystal form outside the cell.

Answer:

A few of the positive particles aimed at a gold foil seemed to bounce back.

Explanation:

Rutherford's experiment took the search for the structure of the atom a step further. In this experiment, a narrow beam of alpha particles emitted from a source was used to bombard a thin gold foil.

The scattering of the alpha particles was detected by a movable ZnS screen. It was found that most of the alpha particles followed a straight path through the gold foil but some were scattered through large angles and some even scattered backwards.

Following this experiment, Rutherford decided on his planetary model of the atom in which the nucleus is at the core of the atom with electrons moving round the nucleus in orbits. Rutherford was awarded a Nobel prize for this work.

Answer:

a

Explanation:

edge 2020

This question is incomplete, here´s the complete question.  

How does the percentage of monounsaturated and polyunsaturated fatty acids in olive oil compare to that of canola oil? Match the words in the left column to the appropriate blanks in the sentences on the right.

Olive oil has about ____ monounsaturated fats, while canola oil has about ___.

Olive oil has about ___ polyunsaturated fats, while canola oil has about ___.

6%

10%

30%

84%

5%

65%

Answer:

Olive oil has about 84% monounsaturated fats, while canola oil has about 65%.

Olive oil has about 5% polyunsaturated fats, while canola oil has about 30%.

Explanation:

Olive and canola oil are the major sources of monounsaturated fatty acids. Although vegetable oils usually have high concentrations of polyunsaturated fatty acids and less monounsaturated fats, olive and canola oils have comparatively less polyunsaturated fatty acids, and more monounsaturated fatty acids.

Answer:

The scientific term for table salt is Sodium chloride.

Explanation:

The answer is sodium chloride.

It is composed of sodium and chloride. Like,

[tex] {na}^{ + } + {cl}^{ + } = nacl[/tex]

so, it's name is sodium chloride.

Respuesta:

21.8 L

Explicación:

Paso 1: Escribir la reacción balanceada

CaCO₃ ⇒ CaO + CO₂

Paso 2: Convertir 450 g de CaCO₃ a moles

La masa molar de CaCO₃ es 100.09 g.

450 g × (1 mol/100.09 g) = 4.50 mol

Paso 3: Calcular los moles de CO₂ que se forman a partir de 4.50 moles de CaCO₃

La relación molar de CaCO₃ a CO₂ es 1:1. Los moles de CO₂ formados son 1/1 × 4.50 mol = 4.50 mol.

Paso 4: Convertir la temperatura a Kelvin

Usaremos la siguiente expresión.

K = °C + 273.15 = 200°C + 273.15 = 473 K

Paso 5: Calcular el volumen de CO₂

Usaremos la ecuación del gas ideal.

P × V = n × R × T

V = n × R × T / P

V = 4.50 mol × (0.082 atm.L/mol.K) × 473 K / 8 atm

V = 21.8 L

a sentence for 'could': could u pass me the salt?

a sentence for 'would': what would you do if u were the president of usa?

sentence for 'should': you should practise ur spellings before the exam. :)

hope this helps!