what energy is created when an electron is added to a neutral atom of an element, forming a negative ion?

Iridium (Ir) is a element which is metal. Therefore, the correct option is option C among all the given options.

Metal is any of a group of substances with strong thermal and electrical conductivity, malleability, ductility, as well as high light reflection. Typically, metals are crystalline solids. The free-electron hypothesis provides the best justification for the high thermal and electrical conductivity and high of the simple elements.

They typically have a very straightforward crystal structure that is characterized by dense atom packing and a high level of symmetry. Metal atoms often have fewer than half of their total number of electrons in the outermost shell. This property makes metals less likely to combine to create compounds. Iridium (Ir) is a element which is metal.

Therefore, the correct option is option C. Iridium (Ir) is a element which is metal.

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Answer:

End point.

Explanation:

The end point is the point at which the indicator changes color in a titration.

The end point generally lags behind the neutralization point in a reaction where we have taken acidic or basic indicator.

Indicators show a change or appearance in color at particular pH. This pH is achieved after point of neutralization. However for some indicators the change in color can also be observed at point of neutralization or completion of reaction exactly. In that case equivalence point and end point will coincide.

The best tool for Derek to use for delivering 25.00 mL of a sodium hydroxide solution is a volumetric pipette. Volumetric pipettes ensure precise volume measurements needed in laboratory settings.

To accurately measure and deliver 25.00 mL of a sodium hydroxide solution, the best tool for Derek to use is a volumetric pipette. Volumetric pipettes are specifically designed for precise volume measurements and are commonly used in laboratory settings to ensure accuracy.

Here’s a step-by-step guide on how Derek can use the volumetric pipette:

By using a volumetric pipette, Derek can be confident that he has delivered exactly 25.00 mL of the sodium hydroxide solution, which is critical for accurate chemical preparations and reactions.

What happens when  nitrogen fills its valence  shell is that 3 electron are gained  creating N3- ion

calculation

Answer:

[tex]4Fe+3O_2\rightarrow 2Fe_2O_3[/tex]

Explanation:

The unbalanced reaction of the reaction between iron and oxygen is shown below as:-

[tex]Fe+O_2\rightarrow Fe_2O_3[/tex]

On the left hand side,  

There is 1 iron atom and 2 oxygen atoms

On the right hand side,  

There are 2 iron atoms and 3 oxygen atoms

Thus,  

Right side, [tex]Fe_2O_3[/tex] is multiplied by 2.

Left side, [tex]O_2[/tex] must be multiplied by 3 and [tex]Fe[/tex] by 4 so to balance iron and oxygen.

Thus, the balanced reaction is:-

[tex]4Fe+3O_2\rightarrow 2Fe_2O_3[/tex]

It means the waves collides and constructive interference occurred.

If the two waves coming from the opposite direction collide with each other, there are two way of their interference.

Hence in experiment there will be constructive interference.

Answer:

C.

Explanation:

I took the test!

Final answer:

The chemical formula for fluorine in its standard state is F₂, which is a diatomic gas due to fluorine's high electronegativity.

Explanation:

The chemical formula for fluorine in its standard state is F₂. Fluorine is a diatomic molecule, meaning it naturally pairs up with another fluorine atom to form a molecule in its most stable and common form, denoted as F₂ gas. Rule 3 of assigning oxidation states is vital for fluorine due to its strong electronegativity, which is the highest among all elements. Thus, the F-F molecule can provide a reference point for calculating oxidation states of other elements.

Explanation:

When the water freezes, the variable which changes is the temperature because as we reduce the temperature, the particles will come closer to each other and the average kinetic energy of the particles of water decreases. Hence, the water freezes below 0°C.

In the case of melting, the temperature is increased which means that the particles move away from each other and the average kinetic energy of the particles of water at this temperature increases. Hence, the water melts above 100°C.

The atomic weight of hydrogen is approximately 1 atomic mass unit. It is the lightest element with an atomic number of 1 and it consists mainly of one proton and one electron. The atomic weight represents the weighted average atomic mass of hydrogen's isotopes.

The atomic weight of hydrogen is often considered to be 1. This value is based on a standard atomic weight scale where hydrogen, the lightest element with the atomic number, Z, of 1, sets the reference point for the scale. The atomic mass of hydrogen is approximately 1 atomic mass unit (u), which is a unit derived from the mass of a carbon-12 atom. Since a hydrogen atom consists of one proton and one electron, and has no neutrons, its atomic mass is very close to 1 u. The actual mass of a hydrogen atom is about 1.7 x 10⁻²⁷ kg. However, in chemical reactions and on the periodic table, a weighted average of the atomic masses of the different isotopes of hydrogen (such as protium with no neutrons, deuterium with one neutron, and tritium with two neutrons) is used, leading to a slightly different average atomic mass of approximately 1.008. It is critical in chemistry to distinguish between the atomic number, which is the number of protons in the nucleus of an atom, and the atomic mass or atomic weight, which is the weighted average mass of an atom's isotopes as they occur naturally.

Final answer:

To calculate the number of atoms in 4.2 moles of sulfur atoms, use Avogadro's number. To calculate the mass of these 4.2 moles, multiply the number of moles by the molar mass of sulfur.

Explanation:

To calculate the number of atoms in 4.2 moles of sulfur atoms, you can use Avogadro's number. Avogadro's number is equal to 6.022 x 10^23 atoms per mole. So, by multiplying the number of moles (4.2) by Avogadro's number, you can determine the number of atoms:

Number of atoms = 4.2 moles * (6.022 x 10^23 atoms/mole) = 2.53 x 10^24 atoms.

To calculate the mass of 4.2 moles of sulfur atoms, you need to know the molar mass of sulfur. The molar mass of sulfur is 32.07 g/mol. Multiply the number of moles by the molar mass to find the mass:

Mass = 4.2 moles * 32.07 g/mol = 134.754 g.

Final answer:

To find the oxidation numbers in Fe(NO3)2, we acknowledge that the sum is zero for a neutral compound. Each nitrate ion has an oxidation number of -1; thus, nitrogen is +5, and each oxygen is -2. Therefore, iron must have an oxidation number of +2 to balance the negative charge of the two nitrates.

Explanation:

To determine the oxidation numbers of elements in Fe(NO3)2, we follow the general rules for oxidation states. First, we know that the chemical compound as a whole is neutral, so the sum of all oxidation numbers in Fe(NO3)2 must be zero. Secondly, the oxidation number of oxygen is typically -2. In each nitrate ion (NO3−), there are three oxygen atoms contributing to a total of -6. The nitrate ion has a charge of -1, which means the nitrogen must have an oxidation number of +5 to balance the -6 from the oxygen atoms (x + 3(−2) = −1, x = +5).

Since there are two nitrate ions in Fe(NO3)2, this gives us a total negative charge of -2 from both nitrate ions. Consequently, the iron (Fe) must have an oxidation number of +2 to neutralize the charge from the nitrates (Fe2+). Thus, the complete set of oxidation numbers in Fe(NO3)2 is Fe2+ and two NO3− ions, with nitrogen being +5 and oxygen -2 in each nitrate ion.

atoms are made of 3 types of sub atomic particles; electrons, protons and neutrons

Of these particles, electrons are involved in the chemical reactions.

Therefore chemical properties of the element are determined by the electrons, and that too mostly the valence electrons. Valence electrons are the electrons in the outermost energy shell.

Atoms with same number of valence electrons have similar chemical properties. atoms having same number of valence electrons are classified into groups.

So elements of the same group have same number of valence electrons, hence similar chemical properties

Ca has 2 valence electrons so it belongs to group 2. Of the given elements

only Mg belongs to group 2. Therefore Mg has the most common properties with Ca

Answer:

The molecular formula is Fe₂O₃

Explanation:

The molar mass of the compound is 199.55 g/mol; this means that if we have 1 mol of the compound, we'd have 199.55 g, we'd also have:

Now we calculate the moles of each element present in the given masses, using their atomic masses:

Then in 1 mol of the compound, there's 2.50 mol Fe and 3.75 mol O:

We convert the coefficients into integers (Divide them by the lowest number among them and multiply them by two):

A testable, precise prediction of what you believe will occur in a scientific experiment that is based on your observations and past knowledge is called a scientific hypothesis. Here the correct option is D.

A scientific theory must satisfy two requirements in order to be accepted: it must be testable and falsifiable. A theory is not scientific if it cannot be verified through observation. A hypothesis is a rough explanation for a group of facts that can be put to the test by specific follow-up research.

Among the given options, if a plant is exposed to only blue light, the plant will grow more slowly can be proved by performing an experiment. Thus it is an example of a scientific hypothesis.

Thus the correct option is D.

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Option C: The dissociation of a polar covalent compound in water.

Sugar is made up of sucrose molecules containing polar covalent bonds. They have same type of oxygen-hydrogen covalent bonds that are present in water.

Since, sugar is not an ionic compound, option a and option b are incorrect. Also, due to same type of bonding in water and sugar molecules there will be no such force of attraction between them, this will opt out the option d.

Thus, dissolution of sugar in water is the dissociation of a polar covalent compound in water and option c is correct.

Final answer:

The dissolution of sugar in water is due to the strong pull of water molecules on a polar covalent compound, like sugar, and is best explained by option d.

Explanation:

The dissolution of sugar in water is best described by option d, a strong pull of water molecules on a polar covalent compound. Sugar molecules are classified as polar covalent compounds because they contain regions of hydrogen-oxygen polar bonds. Due to the polarity of the water molecule, it can interact with these polar regions within sugar molecules through intermolecular forces. These interactions facilitate the separation of the sugar molecules into the solution, where they are surrounded by water molecules, leading to dissolution.

Water itself is a polar molecule, having a partial negative charge on the oxygen atom and a partial positive charge on the hydrogen atoms. Water molecules can surround the sugar molecules, aligning their charges with the opposite charges in the sugar molecule. This is what strongly pulls the sugar molecules apart and allows them to interact with more water molecules until they are evenly dispersed — thus the sugar is dissolved in the water due to the hydration process.

Answer:

A) CHCl3

Explanation:

Polarity arises due to the difference in the electronegativity between two atoms forming a chemical bond. This difference also creates a dipole. A molecule is said to be polar if it has a net dipole moment. In symmteric molecules the dipole moments tend to cancel out making them non-polar.

A) CHCl3 is a tetrahedral molecule in which the central C atom is bonded to 3 Cl and 1 H atom. This molecule is not symmteric since there are 3 C-Cl and  C-H bonds. Therefore, it will have a net dipole and will be polar

B) CCl4 is also a tetrahedral molecule, but symmetric in nature. Hence it will be non-polar

C) CO2 is a linear molecule where the dipole moments cancel out making it non-polar

C) CH4 is also a tetrahedral molecule and symmetric in nature. Hence it will be non-polar

A. CHCl₃ (chloroform) is the polar compound due to its tetrahedral structure with non-identical atoms and the resulting imbalance in electron distribution.

The compound likely to be a polar compound is CHCl₃. CHCl₃, or chloroform, is a polar molecule due to the uneven distribution of charge within its tetrahedral structure. Although the molecule has a tetrahedral geometry, the atoms bonded to the central carbon are not identical; there is one hydrogen and three chlorine atoms. Chlorine is more electronegative than carbon, and carbon is more electronegative than hydrogen, resulting in polar C-Cl bonds with a larger bond moment compared to the C-H bond. The difference in electronegativity and the arrangement of the atoms causes the bond dipole moments not to cancel out, yielding an overall dipole moment for the molecule. In contrast, molecules such as CCl₄ and CO₂ have symmetrical shapes and equal sharing of electrons, which result in nonpolar characteristics, while CH₄ also has a symmetrical tetrahedral structure with no significant differences in the electronegativity of the bonded atoms, rendering it nonpolar as well.

Answer is: the quantity of heat that is required to raise the sample’s temperature by 1°C (or Kelvin).

Heat capacity of a sample is expressed in units of thermal energy per degree temperature (J/K).

Heat capacity is often defined relative to a unit of mass (J/kg·K or J/g·K), prefixed with the term specific.

For example, specific heat capacity of water is 4.184 J/g·K (Cp(H₂O) = 4.184 J/g·K).

The statement that defines the heat capacity of a sample is the quantity of heat that is required to raise the sample’s temperature by 1°C (or Kelvin).

Heat capacity of a substance refers to the quantity of heat that is required to raise the temperature of the substance by 1°C or K.

The heat capacity of a substance can be measured in Jg/°C or JK/g.

The heat capacity of water molecule is 4.184 Jg/°C.

Therefore, the statement that defines the heat capacity of a sample is the quantity of heat that is required to raise the sample’s temperature by 1°C (or Kelvin).

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To find the molecular formula of a compound, one must first determine the empirical formula based on mass percentages, calculate the molar mass using the ideal gas law, and then compare the empirical formula mass with the molar mass.

To establish the molecular formula for the gaseous compound, we start by calculating its empirical formula using the percentages given: 82.66% carbon (C) and 17.34% hydrogen (H). With the assumption of a 100 g sample, we have 82.66 g of C and 17.34 g of H. Converting these masses to moles, we use the atomic mass of carbon (12.01 g/mol) and hydrogen (1.01 g/mol), yielding:

The empirical formula is obtained by dividing by the smaller number of moles:

Since we cannot have half a hydrogen in a formula, we multiply by 2 to get whole numbers, giving us an empirical formula of C2H5. Next, we calculate the molar mass (MM) using the provided conditions (158 mL at 556 mmHg and 25
C with a mass of 0.275 g). We apply the ideal gas law:

PV = nRT

Converting the pressure to atmospheres (556 mmHg / 760 mmHg/atm) and the volume to liters (158 mL / 1000 mL/L), and using the value of R (0.0821 Latm/molk), the molar mass can be calculated. Finally, comparing the empirical formula mass (EM) to the MM obtained allows for the determination of the molecular formula by finding the ratio between MM and EM, which tells us how many empirical units are in the molecular formula.

To summarize:

Your answer will be C. It's not D i just took the test

Answer:

This is the evidence of physical change.

Explanation:

When the substance is heated, its form is changed but identity remain the same, it is then a physical change. In physical change substance can only change their phases but not lose the identity. For example it may change its state from solid to liquid and liquid to gas.

Physical change:

The changes that occur only due to change in shape or form but their chemical or internal composition remain unchanged.

These changes were reversible.

They have same chemical property.

These changes can be observed with naked eye.

Example s:

Water converting to Ice .

Water converting to gas.

In this water molecule remain the same only they rearrange themselves that change its state of mater not composition.

Chemical change:

The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.

These changes are irreversible .

These changes occur due to chemical reactions .

These may not be observed with naked eye .

Examples:

combustion of fuel or wood: that oil or wood convert into energy, CO2 and ash in case of wood .

Boiling of egg: that change the chemical composition of protein in the egg

The modern periodic table arranges elements in order of increasing atomic number, which corresponds to the number of protons in an atom's nucleus. The increasing atomic number across the table helps predict properties and interactions of elements.

The modern periodic table is an essential tool in chemistry, used to catalog and organize the known elements. The table is arranged in order of increasing atomic number, which is equivalent to the number of protons in an atom's nucleus.

For instance, Hydrogen has an atomic number of 1 and is the first element on the table, while Helium has an atomic number of 2 and is the second element. As you move down and across the table, the atomic number continues to increase.

This help scientists to predict the properties of various elements, their reactivity, and how they might interact with other elements.

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"The density of the water is given by the mass and the volume." The volume occupied by water is 1.63 L and ice cannot be contained in water as it has more volume.

Volume has been inversely related to the density as increased volume decreases the density by their inverse relation. The division of the mass and volume gives the density of the substances.

Given,

Density of water = 0.997 g/cm³

Density of ice = 0.917 g/cm³

The volume of the soft drink bottle = 1.50 L

The volume of ice is calculated as:

Volume = mass ÷ density

V = 1495.5 ÷ 0.917

= 1630 cm³

The unit conversion is done as:

1 cm³ = 1 mL

1630 cm³ = 1630 mL = 1.630 L

Ice cannot be fitted into the soft drink bottles as the volume of ice 1.63 L is more than the volume of the bottle, 1.50 L.

Therefore, the volume of ice is 1.630 L.

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