please someone explain this I dont get it at all. how do we know that the 4th electron came from 2p because it's at 4th ionisation? why is it talking about 3s?? how do overall know that aluminium is in group 3 from the table??? thanks​

Answer:

B. Oxygen

Explanation:

Basically count each arrow since each arrow represents an electron. Then use the periodic table to find the element with 8 electrons, which is oxygen. Also, if you know the orbital patterns, you can identify that the 2p orbital represents an element in Group 16.

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]

Explanation:

Your required answer is sulpher.

Hope it helps...

Answer:

Total energy consumed = 1,882.8 joules

Explanation:

Given:

Calories burned = 450 calories

Find:

Total energy consumed

Computation:

1 calorie = 4.184 joules

So,

450 calories = 4.184 × 450

450 calories = 1,882.8 joules

Total energy consumed = 1,882.8 joules

Answer:

1) electron=19 Proton=19 Neutron=39-19=20

2) 1

3) in pic

Answer:

(i)electrons = 19; Protons = 19 Neutrons =39-19=20

(ii) 1

(iii) 2,8,8,1

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Answer:

C6H14 + 13/2O2 -------> 6CO2 + 7H2O

Explanations

combustion means burning with excess oxygen

Answer:

For example, in a molecule of aspirin, C9H8O4, there are 9 carbon atoms, 8 hydrogen atoms and 4 oxygen atoms. compound.

Explanation:

The carbon atoms are in 0.650 gram tablet of aspirin (C9H8O4) is 3.24 x 10² atoms.

Atoms are defined as the smallest unit of matter that can be divided without releasing electrically charged particles.

After the Big Bang, the building blocks of matter were generated is known as atoms.

Molar mass of aspirin = 180.2 g

Number of carbon atoms

= 0.650 g x 1 mole aspirin / 180.2 g x 9 / 1 mole aspirin

= 3.24 x 10² atoms

Thus, the carbon atoms are in 0.650 gram tablet of aspirin (C9H8O4) is 3.24 x 10² atoms.

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Answer:

Calcium: Alkaline Earth

Sodium: Alkali Metal

Hope it helps!

Answer:

Calcium is in Alkaline Earth

Sodium is in Alkali Metal

If an object's mass is 70 g, and its volume is 10cm cubed,  its density is 7 centimeter cube.

The density of any solid substance is the unit of the area occupied by it in per centimeter of the cube of the volume in the given sample and calculated by dividing the mass and the volume of the compound unit will be centimeter cube.

The mass of the given object is 70 gram and the volume is given is 10 cm to find the density,

                       Density = mass of object / volume of object

substituting the value in the formula,

                 Density = 70 / 10

                 Density = 7 centimeter cube.

Therefore, the density of the given object will be 7 centimeter cube if  an object's mass is 70 g, and its volume is 10cm cubed.

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Answer:

a colloid and a solution

Explanation:

When solute particles completely dissolve in a solvent, a true solution is formed. The solute particles in this case are so little that they can not be seen with naked eyes. A true solution does not scatter rays of light.

In a false solution, the solute particles are larger than the solute particles in true solutions but are not large enough to be seen with naked eyes. False solutions scatter rays of light. False solutions are also called colloids.

The major difference between a solution and a colloid is that colloids scatter light rays (Tyndall effect) while a true solution does not scatter light rays.

Answer:

0.009871

Explanation:

[tex] 9.871\times 10^{-3} = 0.009871[/tex]

Answer:

.009871

Explanation:

Answer:

When you don't have a complete reaction.

Explanation:

Happens a lot between a solvent and a solute. The solute may not bind well with the solvent I.e. water.

Answer:

29

Explanation:

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

Explanation:

Answer:t

Explanation:

In everyday life, four states of matter are visible: solid, liquid, gas, and plasma.

Of course, matter also has other states, such as Bose-Einstein density and Fermion density, but these states are only observed under certain conditions.

Answer:

A. Weathering breaks down rocks; Deposition leaves them in new places.

Explanation:

Weathering is basically the complete process of rocks breaking apart.  In contrast, deposition is when the rocks are moved and carried away from their original place and put in new locations.

Answer:

a

Explanation:

Answer:

0.571moles

Explanation:

The Avogrado's number or constant denoted by NA will be used for this question.

The Avogrado's number = 6.022 × 10^23 particles, is contained in 1 mole of a substance.

To get the number of atom/particles in a substance, the formula: N= n × NA is used.

Where; N= Number of atoms in

substance

n= number of moles

NA= Avogadro's constant

Hence, to find the number of moles of copper equivalent to 3.44 × 10^23, we say: n= N / NA

That is, n = 3.44 × 10^23 / 6.022 × 10^23

= 0.5712

Therefore, 0.571 moles of Copper (Cu) is equivalent to 3.44 × 10^23 atoms of Copper.

Answer:

B

Explanation:

Isotopes have the same number of protons but different number of neutrons.

The true statement is,

So, option C is correct one.

The isotopes have different physical properties like freezing point , mass, melting or boiling point etc because they have different mass number .

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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.

Answer:

When a chlorine atom gains an electron, its outermost principal energy level achieves an octet. In this case, the ion has the same outermost shell as the original atom, but now that shell has eight electrons in it. Once again, the octet rule has been satisfied.

Explanation:

Answer:

YES

Explanation:

If we put a plant in a room with an orange light source, then it will grow more efficiently than a plant exposed to other colors.

Yes the wavelength of light (R.O.Y.G.B.I.V.) affect a plant’s growth.

The wavelength of light can be defined as the distance between the two successive  troughs of the light wave, and  It is denoted by the Greek letter lambda (λ), simply it can be said as the distance between one crest or trough of one wave and the next wave is known as wavelength.

The Visible Light having wave length ranges from 400 nm to 700 nm and the spectrum of visible light has a number of colors having different wavelengths.

For example, The violet color have the shortest form of wavelength whereas the red color have the longest wavelength, wavelength is inversely proportional to the frequency like  longer the wavelength of the light have lower is the frequency.

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Answer:

Ethanamine (also known as ethylamine)

Explanation:

The compound that is requested by the question is ethanamine. Its trivial name is ethylamine.

It is a compound that contained the ethyl moiety (CH3CH2-) as well as the amine moiety (-NH2).

Ethanamine has a structure that can easily be determined by the statements in the question.

The structure of ethanamine is shown in the image attached.

Answer:

What is the name of this compound?

                                                                                    H       H

                                                                                    │       │

                                                               H ── N ── C ── C ── H

                                                                          │       │        │

                                                                          H      H        H

❌ A) ethanal

❌ C) ethanoic acid

❌ D) methyl ethanoate

I Took Question Test And Have Day.

Answer:

The correct option is;

d) LiF

Explanation:

The Lattice energy of ionic compounds can be calculated using the modified Coulomb's law as follows;

[tex]U = \dfrac{k' \cdot Q_1\cdot Q_2}{r_0}[/tex]

Where;

Q₁ and Q₂ =  The ionic charges

k' = A constant depending on the ionic and valence configuration

r₀ = The distance between the two nucleus

Given the four compounds each of the metallic ions are of the same group (group one) have the same (only one) valence electron, and are combined to the same ion (fluoride ion) such that Q₂, is the same for all compounds, the factor that will influence the lattice energy more will be the r₀

The sizes of the atoms Li, Na, K and Cs increases as arranged as such Li has the least r₀, and therefore LiF the least  lattice energy

From chemistry test online, we have;

The lattice energy of LiF = -1045 kJ/mole

The lattice energy of NaF = -924 kJ/mole

The lattice energy of KF = -822 kJ/mole

The lattice energy of CsF = -737 kJ/mole.

Answer:

I think it's 7089 because that's my answer to your questions

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:

5.49

Explanation:

pH = - log[3.26 x 10-6] =5.49

Answer:

The words science and technology can and often are used interchangeably. But the goal of science is the pursuit of knowledge for its own sake while the goal of technology is to create products that solve problems and improve human life. Simply put, technology is the practical application of science.

Explanation:

Check the following images

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Answer:

there are 6 significant figures in 107.051

Answer:

There Are 6 Significant Numbers

Explanation: But some problems stop at the . so it could 3 if im right but go with 6!

The transformation of liquid into solid when it reaches when it's temperature is below freezing point.

Answer:

Freezing:

When liquid is converted to solid, the process is called freezing.

Conditions for freezing:

1) Temperature must be lowered.

2) The temperature should be below 0 degree centigrade.

Example:

The conversion of "liquid water" into "ice".

=> We can use a "freezer" to freeze things.

18.8gBa(NO3)2 》》》》gN 》》》》 2.016gN