Which pure substance can be classified as an element? -H2 -NO3 -NaCl -H2SO4

In experiments, only one variable is changed at a time to establish a clear cause-and-effect relationship between the changed variable and the observed result. This approach is known as the control method.

In an ideal simple experiment, it is important to change only one variable from trial to trial to confirm the resulting impact is solely due to that one specific variable. This is because experiments are conducted to identify the cause-and-effect relationships between variables. Changing only one variable at a time (while keeping others constant) establishes a clear relationship between the changed variable and the observed result. If multiple variables are changed simultaneously, it would be challenging to decipher which variable caused the observed change in results. This approach of changing one variable at a time is also referred to as the control method.

https://brainly.com/question/24778201

#SPJ2

Answer:

one

Explanation:

The valence electron configuration for antimony (Sb) is:

Sb = 5s²5p³5d⁰

In SbCl₅²⁻, antimony has a -2 charge i.e. it has 2 additional electrons

Sb²⁻ = 5s²5p⁵5d⁰

Following a two electron transition from p→d orbital we have:

Sb²⁻ = 5s²5p³5d²

There is a total of 5 unpaired electrons (3 in the p and 2 in the d) which can form five bonds with the 5 Cl atoms.

Thus the hybridisation of Sb in SbCl₅²⁻ is sp³d²

The hybridization of [tex]{\text{SbCl}}_5^{2 - }[/tex] is [tex]\boxed{{\text{s}}{{\text{p}}^3}{{\text{d}}^2}}[/tex]. Antimony (Sb) can accept 12 electrons.

Further Explanation:

Prediction of hybridization:

The hybridization can be determined by calculating the number of hybrid orbitals (X) which is formed by the atom. The formula to calculate the number of hybrid orbitals (X) is as follows:

[tex]\boxed{{\text{X = }}\frac{1}{2}\left[ {{\text{VE}} + {\text{MA}} - c + a} \right]}[/tex]

Where,

Note: In MA only monovalent species should be considered and for divalent atoms or groups MA is equal to zero.

Generally, the least electronegative atom is considered as the central atom. Calculate the hybridization as follows:

1. If the value of X is 2 then it means two hybrid orbitals are to be formed and thus the hybridization is sp.

2. If the value of X is 3 then it means three hybrid orbitals are to be formed and thus the hybridization is [tex]s{p^2}[/tex].

3. If the value of X is 4 then it means four hybrid orbitals are to be formed and thus the hybridization is [tex]s{p^3}[/tex].

4. If the value of X is 5 then it means five hybrid orbitals are to be formed and thus the hybridization is [tex]s{p^3}d[/tex].

5. If the value of X is 6 then it means six hybrid orbitals are to be formed and thus the hybridization is [tex]s{p^3}{d^2}[/tex].

The ground state electronic configuration for antimony (Sb) is [tex]\left[ {{\text{Kr}}} \right]{\text{ }}4{d^{10}}5{s^2}5{p^3}[/tex]

Therefore, the valence electrons associated with antimony (Sb) atom are 5.

Since chlorine is a monovalent atom thus the total number of monovalent atoms surrounding the central atom (MA) is 5.  

Since the molecule is an anionic species and has -2 charge thus the value of a is 2.

Substitute these values in the above formula.

[tex]\begin{aligned}{\text{X}}&=\frac{1}{2}\left[{{\text{VE}}+{\text{MA}}-c+a}\right]\\&=\frac{1}{2}\left[{{\text{5}}+{\text{5}}-0+2}\right]\\&=\frac{1}{2}\left[{12}\right]\\&=\boxed6\\\end{aligned}[/tex]

Since the value of X is 6, it means 6 hybrid orbitals are to be formed and therefore the hybridization of [tex]{\mathbf{SbCl}}_{\mathbf{5}}^{{\mathbf{2}} - }[/tex] is [tex]{\mathbf{s}}{{\mathbf{p}}^{\mathbf{3}}}{{\mathbf{d}}^{\mathbf{2}}}[/tex].

The formula to calculate total number of valence electrons of [tex]{\mathbf{SbCl}}_{\mathbf{5}}^{{\mathbf{2}} - }[/tex] is as follows:

Total valence electrons= [(1) (Valence electrons of Sb) + (5) (Valence electrons of Cl) + Negative charge]

[tex]\begin{aligned} {\text{Total valence electrons}}\left({{\text{TVE}}}\right)&=\left[{\left({\text{1}}\right)\left({\text{5}}\right)+\left({\text{5}}\right)\left({\text{7}}\right)+\left(2\right)}\right]\\&=42\\\end{aligned}[/tex]

According to the Lewis structure of [tex]{\text{SbCl}}_{\text{5}}^{2 - }[/tex] ( refer to the image attached) central atom, Sb has an expanded valence shell in which 12 electrons are present. Therefore, Antimony (Sb) can accept 12 electrons.

Learn more:

1. Molecular shape around the central atoms in the amino acid glycine: https://brainly.com/question/4341225

2. Component of John Dalton’s atomic theory:https://brainly.com/question/2357175

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Covalent bonding and molecular structure

Keywords: Hybridization, antimony, geometry, sp3d2, steric number, 6,d orbital, SbCl52-, Lewis structure, hybridization of SbCl52-, central atom, chlorine, shape, d2sp3, total valence charge.

Answer:

Density=mass / volume.

0.75= mass / 120.

mass= 0.75×120.

mass=90g

The estimated digit in the measurement 0.503 L is the last digit, 3.

In chemistry, the most basic form of matter which can't be broken down further by conventional chemical methods is an element, specifically its atoms. They are represented on the Periodic Table and have a unique number of protons.

In the field of Chemistry, the basic form of matter which cannot be further broken down by traditional chemical methods is known as an element. These elements are represented on the periodic table and include things such as Hydrogen, Oxygen, and Iron. An element's atoms all have the same number of protons, and this is what uniquely defines them. Therefore, when you ask about the most basic form of matter that can't be broken down any further, we are talking about these elements, or more specifically, their atoms.

https://brainly.com/question/36868053

#SPJ12

Water is a polar molecule because it has a dipole moment with one end having a slight positive charge and the other a negative charge due to uneven distribution of electron density. This polarity leads to water's unique properties including its solvent capabilities, high boiling point, and its ability to form hydrogen bonds.

When we say that water is a polar molecule, it means that it has a dipole moment where one end of the molecule has a slight positive charge and the other end has a slight negative charge. This is due to the uneven distribution of electron density as oxygen is more electronegative than hydrogen, causing the hydrogen atoms to carry a slight positive charge and the oxygen atom to carry a slight negative charge. This polarity results in water's unique properties such as its ability to dissolve many substances (its solvent capabilities), its high boiling point, and its ability to form hydrogen bonds with other water molecules.

#SPJ12

Final answer:

The third law of thermodynamics is aligned with our understanding of matter and heat transfer because it is consistent with the tendency of energy to spontaneously transfer from hotter to colder systems, a concept supported by the second law of thermodynamics and energy conservation principles.

Explanation:

The student's question addresses why the third law of thermodynamics is supported by our current understanding of matter, particularly considering that heat transfers occur only between systems with different temperatures. The third law of thermodynamics implies that as the temperature of a system approaches absolute zero, the entropy, or disorder, of the system approaches a minimum value. This law is supported by the fact that matter has a property called thermal conductivity, meaning that energy is transferred spontaneously from a higher temperature system to a lower temperature system because the disorder is more probable, and there is a tendency towards energy dispersion.

These concepts are also tied to heat, which is the process of energy transfer due to temperature differences, and the second law of thermodynamics, highlighting that energy transfers are never completely efficient and some energy is always lost as heat. Furthermore, the concept of energy conservation within the first law of thermodynamics states that the total energy of a system is conserved during such interactions. Overall, this understanding is crucial for comprehending the limitations and behaviors in the transfer of energy between systems.

The Huronian Supergroup is interesting to scientists due to its age, the presence of primitive rock, and evidence of past watery environments. It gives unique insight into the planet's early history.

The Huronian Supergroup rock formation is particularly interesting to scientists for many reasons. This rock formation is known for being one of the oldest exposed rock formations available for study, providing crucial insights into the early history of the Earth.

One significant feature is the presence of primitive rock, which has largely escaped chemical modification by heating. This kind of rock is usually only found in comets, asteroids, and small planetary moons, so its presence on Earth in the Huronian Supergroup is of particular interest to scientists because this material represents the original material out of which the planetary system was created.

The presence of layered sedimentary rock with evidence of evaporation also suggests that this area was once underwater, possibly a shallow saltwater lake. The presence of hematite within the rocks, which forms only in watery environments, also supports this theory. This information is vital to creating accurate models of the past climates and environments of the planet.

https://brainly.com/question/34277680

#SPJ11

An atom of boron contains five electrons. The first shell is filled with 2 electrons and the second shell will hold the remaining 3 electrons. The fifth electron will occupy a 2p orbital.

An atom of boron with atomic number 5 contains five electrons. The first shell, n = 1, is filled with 2 electrons, and the second shell, n = 2, can hold up to 8 electrons. Since boron only has 5 electrons, 3 electrons will occupy the n = 2 shell. The fifth electron will then occupy the next energy level, which is a 2p orbital.

There are three degenerate 2p orbitals with magnetic quantum numbers m₁ = −1, 0, +1. The electron can occupy any one of these p orbitals. When drawing an orbital diagram, we include empty boxes to represent the p orbitals in the same subshell that we are filling.

https://brainly.com/question/38401227

#SPJ3

We simply get the sum of the product of each mass and caloric values.

Total energy = 19 g * 9 kcal / g + 20 g * 4 kcal / g + 28 g * 4 kcal / g

Total energy = 363 kcal

Rounding of f to 2 significant fig:

Total energy = 360 kcal

The measure of heat and energy present in the fuel and food is called the calorific value. The calorific value is measured in kilojoule per kilogram (KJ/Kg)

The total energy of one meal is calculated by directly adding the energy given by carbohydrates, fats and proteins.

The energy can be calculated as:

       Then, the energy from 20 g of carbohydrate = 20* 4 kcal/g

       = 80 kcal/g

       Then, the energy from 19 g of fats= 19* 9 kcal/g

       = 171 kcal/g

       Then, the energy from 28 g of protein = 28* 4 kcal/g

       = 112 kcal/g

      Total energy = 80 kcal/g + 171 kcal/g + 112 kcal/g

       = 363 kcal/g

Therefore, the total amount of kcal of energy present in the cheeseburger is 363 kcal.

To learn more about total energy and calories refer to the link:

https://brainly.com/question/19928430

Final answer:

The net ionic equation for the reaction is Hg2^2+(aq) + 2Cl-(aq) → Hg2Cl2(s).

Explanation:

The net ionic equation for the reaction between aqueous Hg2(NO3)2 and aqueous sodium chloride to form solid Hg2Cl2 and aqueous sodium nitrate is as follows:

Hg2^2+(aq) + 2Cl-(aq) → Hg2Cl2(s)

This net ionic equation represents the actual chemical change that occurs in the reaction, focusing only on the species that are directly involved in the formation of the solid product and neglecting the spectator ions. The balanced molecular equation and complete ionic equation for this reaction include the spectator ions but are not essential to represent the fundamental chemical change.

Explanation:

In [tex]AlCl_{3}[/tex] compound, three chlorine atoms are attached to an aluminium atom.

Since atomic number of aluminium is 13 and it has three extra electrons. So, it donate single electron to each chlorine atom.

Therefore, octet of chlorine gets complete.

As, three chlorine atoms are attached to aluminium so, name of [tex]AlCl_{3}[/tex] is aluminium trichloride.

Answer:

Make a hypothesis ---> Conduct an experiment --->Analyze the experimental data ---> Communicate the results

Explanation:

The most abundant isotope of hydrogen is hydrogen-1, also known as protium, which accounts for over 99.98% of naturally occurring hydrogen, because its mass is closest to hydrogen's average atomic mass on the periodic table.

The most abundant isotope of hydrogen is hydrogen-1 (protium, 1H), which has one proton and no neutrons. This abundance is reflected in the atomic mass of hydrogen on the periodic table, which is approximately 1.008 amu. Since hydrogen-1 is closest to this average atomic mass, it is the most prevalent isotope. Protium represents over 99.98% of naturally occurring hydrogen. In contrast, hydrogen-2 (deuterium, 2H) with one neutron, and hydrogen-3 (tritium, 3H) with two neutrons, are much rarer. Deuterium occurs about 1 in every 10,000 hydrogen atoms, and tritium is even more scarce and is radioactive.

You can see the volume to the bottom of the meniscus. Upon seeing and reading it all you can say is that it is less than 3.6 mL and more than 3.4 mL. So, from what can I see it is 3.54 mL to the bottom of the meniscus.

Final answer:

The amount of liquid in the smaller graduated cylinder is measured by reading at the bottom of the meniscus, with the value estimated to the nearest tenth of a milliliter. To accurately measure 9.7 mL of water, a graduated cylinder is used, allowing for readings with three significant figures. Significance in measurements is determined by the precision of the measuring device.

Explanation:

To determine how many milliliters of liquid the smaller graduated cylinder contains, one should make a reading at the bottom of the meniscus. When measuring the volume of liquid in a graduated cylinder, you must mentally subdivide the distance between the milliliter marks to estimate the measurement more precisely. If the meniscus falls between the 21 and 22 mL marks, you estimate to the nearest tenth of a milliliter to measure the volume as accurately as possible.

For instance, if you are to deliver 9.7 mL of water, you would use a graduated cylinder with markings adequate to measure to the nearest tenth of a milliliter, allowing you to read the volume with three significant figures. This is because graduated cylinders are typically precise enough to measure small amounts in milliliters with that level of precision.

To convert to milliliters and consider significant figures, remember that when working with measured quantities, like the volume of 22.4 L/mol for molar volume, three significant figures is typically the maximum number of significant figures used. Therefore, when reading a graduated cylinder, always consider the precision of the device to determine the correct number of significant figures to report for your measurement.