Elements in the same periodic table have the same

a) number of electrons
b) number of neutrons
c) atomic number
d) number of outer electrons

Answer:In science, a model is a representation of an idea, an object or even a process or a system that is used to describe and explain phenomena that cannot be experienced directly. Models are central to what scientists do, both in their research as well as when communicating their explanations.

Explanation:

Answer:

A Mixture of two elements

Explanation:

Answer:

The correct answer is D: the reactants are generally two ionic compounds in aqueous solution.

Explanation:

A type of reaction in which two reactants participate and exchange ions with each other as the reaction proceeds. Such type of reaction is known as a double displacement reaction. In double displacement reaction, the product formed is precipitate.

Below is the pathway of the double displacement reaction:

AB + CD → AD + CB

In double displacement reaction usually, ionic compounds are involved. The bond formation between the reacting species may be ionic or covalent in nature.

Final answer:

In a double-replacement reaction, two ionic compounds in aqueous solution exchange ions to form two new products, requiring one product to be insoluble for a reaction to occur.

Explanation:

In a double-replacement reaction, the reactants are generally two ionic compounds in aqueous solution. These reactions involve the exchange of anions and cations between the reactants to form two new products. For a reaction to occur, one of the products must be insoluble in water, forming a solid precipitate, or a molecular compound such as water; if both products remain soluble, no reaction has taken place. Energy in terms of heat or light is not a characteristic feature of double-replacement reactions, unlike some other types of chemical reactions.

Examples include reactions where a precipitate, gas, or molecular compound forms, all of which signify a chemical change. The general formula for these reactions is AB + CD → AD + BC, indicating the switch between anions and cations.

To determine which compounds an unknown sample could be, based on its percent composition, involves calculating the empirical formula from the given percentages and comparing it with the provided compound options.

The question involves determining which compounds an unknown sample could be, based on its percent composition of 52.14% carbon, 13.13% hydrogen, and 34.73% oxygen. This requires an understanding of percent composition and the ability to calculate an empirical formula based on the given percentages. Given the complexity of the sample compositions and potential empirical formulas, it's essential to evaluate each option through stoichiometric calculations and compare their empirical formulas derived from the provided compositions to the actual compounds mentioned.

Answer:

The answer is:

The correct option is option C.

[tex]V=36L[/tex]

To calculate the volume of the gas sample, we need to use the Ideal Gas Law, this equation is used to relate the pressure, the volume, the mass and the temperature of a gas, so, we can isolate the volume from it.

The Ideal Gas Law equation is equal to:

[tex]PV=nRT[/tex]

Where,

P is the pressure (in atm)

V is the volume (in liter)

n is the mass of the gass (in mole)

T is the temperature of the gass (absolute temperature)

So, from the statement we know that:

[tex]Pressure=1.3atm\\Temperature=298K\\n=1.9moles\\R=0.082057\frac{L.atm}{mol.K}[/tex]

Then, substituting and calculating we have:

[tex]PV=nRT\\\\V=\frac{nRT}{P}=\frac{1.9moles*0.082057\frac{L.atm}{mol.K}*298K}{1.3atm}=35.74L[/tex]

Now, rounding to the nearest whol number we have that the volume is equal to 36 L.

Hence, the correct option is option C.

Have a nice day!

Answer:

A negative beta particle

Yes

Explanation:

The incomplete equation of the reaction:

                  ²⁰³₈₀Hg → ²⁰³₈₁Tl + ?

In order to balance nuclear equations, we must conserve the mass number and atomic number.

For the mass number; 203 = 203 + a

                                         a = 0

             Atomic number; 80 = 81 + b

                                           b = -1

The unknown has no mass number but an atomic number of -1

This a  negative beta particle and it is designated as ⁰₋₁e

Answer:

1) Electron

2) Yes

Final answer:

The coefficients that will balance the equation N₂ + H₂ → NH₃ are 1 for N₂, 3 for H₂, and 2 for NH₃.

Explanation:

Chemical equations express chemical reactions using symbols and formulas. Reactants on the left side transform into products on the right side. Balancing ensures conservation of mass. Coefficients in chemical equations represent the numerical ratios of reactants and products. They ensure the conservation of mass and atoms. Adjusting coefficients balances the equation, reflecting the correct stoichiometry of the reaction.

The coefficients that will balance the skeleton equation N₂ + H₂ → NH₃ are: 1 for N₂, 3 for H₂, and 2 for NH₃. The coefficients of a balanced equation represent the mole ratio required for the reaction to occur. In this case, one mole of N₂ reacts with three moles of H₂ to produce two moles of NH₃.

Answer:

Calcium Bromide

Explanation:

Metals like Calcium reacts with halogens like bromine to form Metal halides.

Metal + Halogen → Metal halide

The generally accepted names for compounds and elements are the IUPAC names,

Therefore for calcium and bromine, the IUPAC name of the salt formed is calcium bromide.

Answer:

Calcium bromide

Explanation:

   Calcium bromide is mainly used as dense aqueous solutions for drilling fluids. It is also used in medicines, freeze mixtures and photography.

  The nomenclature follows the general rule:

                               Anion Name + Cation Name

    But this is only effective for those salts that are classified as simple salts, which means, salts that dissociate into water and form only one cation and one anion.

    When we work with a salt called double, for example, this rule goes through some adjustments.  It is one that presents in its constitution the presence of two cations accompanying an anion or two anions accompanying a cation. For this reason, when these salts undergo the dissociation phenomenon in water, they release two cations or two anions, depending on the salt with which they are working.

   The double salt that has in its constitution two cations accompanying an anion is called double salt as the cation. To name such a salt, we must use the following naming rule:

           Anion name + name of the two cations

The name of each cation is written according to the order of electropositivity. Thus, the most electropositive cation will be written first.

Answer:

S(s) + O2(g) → SO2(g)

The correct chemical equation that represents the burning of sulfur to form sulfur dioxide is S(s) + O2(g) -> SO2(g). This equation illustrates that one mole of sulfur reacts with one mole of oxygen to produce sulfur dioxide.

The question is asking for the correct formula equation which represents the burning of sulfur to produce sulfur dioxide. The burning of sulfur in the presence of oxygen (O2) results in the formation of sulfur dioxide (SO2). This process can be represented by the following chemical equation:

S(s) + O2(g) —> SO2(g)

This shows that one mole of sulfur (S) reacts with one mole of Oxygen (O2) to produce one mole of sulfur dioxide (SO2).

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Answer:

used to date rocks and other objects based on the known decay rate of radioactive isotopes.

Explanation:

Different methods of radiometric dating can be used to estimate the age of a variety of natural and even man-made materials.

Answer: 2.retains water, 4. are fine grained

Explanation:

Clay is a kind of soil. It exhibit fine grained particles. It retains the organic matter and inorganic minerals. The ability to retain water is because of fine grained size aggregate of clay. As this kind of soil can retain moisture and exhibit minerals it is suitable for the growth of plants.

Answer:H20

Explanation:

because it is the base that contributes electrons

Answer : The Lewis-base in this reaction is, water [tex]H_2O[/tex]

Explanation :

According to the Lewis acid-base theory,

Lewis acid : It is a substance that can accepts pairs of electrons to form a covalent bond.

Lewis-base : It is a substance that can donates pairs of electrons to form a covalent bond.

The given balanced equation is:

[tex]Fe^{3+}+6H_2O\rightarrow [Fe(H_2O)_6]^{3+}[/tex]

In this reaction, [tex]Fe^{3+}[/tex] ion is Lewis-acid and [tex]H_2O[/tex] is a Lewis-base. The [tex]H_2O[/tex] donates electrons to [tex]Fe^{3+}[/tex] ion to form [tex][Fe(H_2O)_6]^{3+}[/tex].

Hence, the Lewis-base in this reaction is, water [tex]H_2O[/tex]

Answer:

The cell wall in plant cells is responsible for cell protection, providing structural support, and giving shape to the cell.

Explanation:

The cell wall in plant cells is responsible for cell protection, providing structural support, and giving shape to the cell.

Answer:

The first option

Explanation:

Answer:

First Question, A, An atom consists of protons, electrons, and neutrons.

Second Question, B, A nucleus consists of protons and neutrons.

Explanation:

Answer:

The three models describes the structure of an atom based on different views.

Explanation:

Plum pudding model described the atom of consisting of negatively charged electrons embedded in positively charged substrates; this was later proven to be false. The Bohr's model described the electrons in an atom to orbit round the nucleus at different energy, the closer it's to the nucleus, the lesser the energy it needs. The Rutherford model claims the the nucleus of the atom contains protons and neutrons which forms the mass of the atom, the electrons surrounds the nucleus and it forms the volume of the atom.

The atom has been the smallest unit of matter. It has been revealed with the varies studies and models proposed to deliver the accepted and well illustrated model.

The Plum pudding model has been the first atomic model proposed by J.J. Thomson. The  Rutherford model has been the well illustrated model of the atom.

The Plum pudding model has been proposed by J.J. Thomson, the Nuclear model by Rutherford, and the Bohr model has been proposed  by Bohr.

The atomic models have been proposed for the atom. All the models have been focused with a central positive nucleus, and negative electrons outside the nucleus.

The plum pudding model considered electrons to be distributed unequally outside the nucleus. The Nuclear model has been considered electrons to be present outside the nucleus in the orbital shells. The Bohr model has been able to explain the quantum address of the electron.

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valence of magnesium is 2

and valence of sulfate-ion is 2 too

answer: MgSO4•7H2O

Answer: [tex]MgSO_4.7H_2O[/tex]

Explanation:

[tex]MgSO_4[/tex] is an ionic compound because aluminium element is a metal and hydrogen element is a non-metal. The bond formed between a metal and a non-metal is always ionic in nature.

The nomenclature of ionic compounds is given by:

1. Positive is written first.

2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written in case of [tex]SO_4^{2-}[/tex] is '-ate'.

Hence, the name of [tex]MgSO_4[/tex] is magnesium sulphate.

The water of crystallization is written as hydrate with the number of water molecules. As the name is heptahydrate, that means 7 water molecules are present.

Therefore, the correct answer is [tex]MgSO_4.7H_2O[/tex]

Answer:

D. Changing the temperature will change Keq.

Explanation:

The equilibrium constant expresses the relationship between the molar concentration of reactants and products. This constant is the Keq. It is temperature dependent and constant at a given temperature.

A change in temperature of an equilibrium system shifts the system to a new equilibrium point. A rise in temperature shifts the equilibrium position to the direction that absorbs heat and vice versa.

In summary, a shift in equilibrium which results from temperature change is actually a change in value of the equilibrium constant.

Answer: D. changing the temperature will change the K eq

Explanation:

The mass of CdCl₂ present in 10.0 mL of a 9 M solution is 16.47 grams.

Given:

Molar mass of CdCl₂ = 183 g/mol

Volume of solution = 10.0 mL = 0.010 L

Molarity of solution (concentration) = 9 M

The molarity (M) of a solution is defined as the number of moles of solute per liter of solution.

Molarity is commonly used to express the concentration of solutions in various chemical reactions and experiments.

To calculate the moles of CdCl₂:

Moles = Molarity x Volume

Moles = 9 M x 0.010 L

Moles = 0.09 mol

Now, to calculate the mass of CdCl₂:

Mass = Moles x Molar mass

Mass = 0.09 mol x 183 g/mol

Mass = 16.47 g

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Answer:

The letter n represents Moles

Explanation:

The Ideal Gas Law. The letter P represents Pressure, the letter V represents Volume, the letter n represents Moles, the letter R represents a constant (a certain number to make the equation work together), the letter T represents temperature.

Yes, In the ideal gas law, 'n' represents the number of moles of a gas. This quantity, along with pressure, volume, and temperature, forms part of the equation PV = nRT, which describes the state of an ideal gas.

The ideal gas law is an equation that describes the relationship between pressure, volume, temperature, and the number of moles of a gas and is generally written as PV = nRT. Here, P stands for pressure, V is volume, R is the ideal gas constant, and T is the temperature in Kelvin. Chemists use moles when working with this law to relate the amount of substances in a more manageable way, as opposed to counting the vast number of individual particles directly.

The law illustrates that, for an ideal gas, if the density (connected to the number of moles) or the temperature goes up, the pressure of the gas also tends to increase. However, this relationship is most accurate when gases do not have strong interactions between particles. In cases where gas particles do interact strongly, such as when gases are not in the ideal state, the ideal gas law may not accurately predict the behavior of the gas.

Answer: In Thomson's model, the atom is composed of electrons called “corpuscles,” he calls the model the plum pudding model of the atom

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Answer:

Hydrogen bonding attracts water molecules to one another and slows the rate of evaporation- last choice

Answer: Option (a) is the correct answer.

Explanation:

Vapor pressure is defined as the pressure exerted by vapors or gas on the surface of a liquid.

So, the greater the intermolecular forces present between the molecules of a substance, lower the vapor pressure.

Evaporation is defined as the ability of a substance's molecules to readily convert into vapors.

In water molecules, there exists hydrogen bonding which is a strong bonding. As a result, molecules are not able to readily convert into vapors due to which no force will exert easily on the surface of water molecules.

Hence, water will have an unusually low vapor pressure.

Thus, we can conclude that water have an unusually low vapor pressure for a liquid because the oxygen-hydrogen bond in a water molecule is unusually strong, which decreases the rate of evaporation.

Answer:

- 90.6 kJ/mol.

Explanation:

ΔHrxn = ∑ΔHf(products) - ∑ΔHf(reactants)

∴ ΔHrxn = ∑ΔHf(products) - ∑ΔHf(reactants)

∴ ΔHrxn = [(2*ΔHf(KCl)) + (3*ΔHf(O₂))] - [(2*ΔHf(KClO₃))] = [(2*(- 436.7 kJ/mol)) + (3*(0)] - [(2*(- 391.4 kJ/mol)] = [- 873.4 kJ/mol] - [- 782.8 kJ/mol] = - 90.6 kJ/mol.

The enthalpy change of the reaction 2KClO3 -> 2KCl + 3O2 is calculated by subtracting the sum of the enthalpies of the reactants from the sum of the enthalpies of the products. The calculation results in an enthalpy change of 90.6 kJ, meaning the reaction is endothermic.

The enthalpy change of the reaction can be calculated by subtracting the sum of the enthalpies of the reactants from the sum of the enthalpies of the products. This is also known as Hess's law.

In this reaction, the reactants are 2 moles of KClO3 and the products are 2 moles of KCl and 3 moles of O2. Hence, the enthalpy of the reaction can be calculated as follows:

Enthalpy change = [2 * (-391.4 kJ/mol)] - [2 * (-436.7 kJ/mol) + 3 * 0 kJ/mol]

= (-782.8 kJ) - (-873.4 kJ)

= 90.6 kJ

Therefore, the enthalpy change of this reaction is 90.6 kJ. If the enthalpy change is positive, the reaction is endothermic meaning it absorbs heat from the surroundings.

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Answer:

Using the table on the right, complete each unit conversion by typing in the correct answer.

85.0 kg =

187 lb    

5.000 km =

3.125 mi

8.000 fl oz =

236.8 mL

14.600 oz =

414.64 g

Explanation:

Bolded ones are the answers for all of the questions!! You're welcomeee

Final answer:

To convert 85.0 kg to pounds, you multiply by the conversion factor of 2.205 lb/kg. The result should maintain the original number of significant figures, which in this case is three, so following the significant figures rule, the answer is rounded to 187 lb.

Explanation:

The student has asked for the conversion of 85.0 kilograms (kg) to pounds (lb). To perform the conversion, the appropriate conversion factor needs to be applied. Given that 1 kg is approximately equivalent to 2.205 lb, you would multiply the mass in kilograms by this conversion factor to find the equivalent weight in pounds. It's important to keep in mind the significant figures of the inexact number when calculating the final answer.

Here's the calculation:

85.0 kg x 2.205 lb/kg = 187.425 lb

However, since we are starting with 85.0 kg (which has three significant figures), our final answer should also have three significant figures. Therefore, we round 187.425 to 187 lb to match the significant figures.

Answer:

The total charge of cations plus anions must equal zero.

Explanation:

The result Barium sulfide which is arrived upon because the total charge of cation plus anions =0

+2+(-2)=0 as seen above. The product is an electrically neutral compound.

Ba²⁺+ S²⁻⇒BaS

The product is a solid which is in the looks of black ash.

Answer:

The answer is: The total charge of cations plus anions must equal zero.

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Explanation:

Answer:

0.004167 J/g°C is the specific heat of a substance.

Explanation:

[tex]Q=m\times c\times \Delta T[/tex]

[tex]Q=m\times c\times (T_{2}-T_1)[/tex]

Where:

Q =  heat absorbed(positive) or released (negative)

m = Mass of substance

c =  specific heat of a substance

[tex]T_1[/tex] = Initial temperature

[tex]T_2[/tex] = Final temperature

We have:

m = [tex]1.0\times 10^4 g[/tex]

c = ? , [tex]T_1=10^oC,T_2=70^oC[/tex]

Q = [tex]2.5\times 10^3 J[/tex]

[tex]2.5\times 10^3 J=1.0\times 10^4 g\times c\times (70^oC-10^oC)[/tex]

[tex]c=\frac{2.5\times 10^3 J}{1.0\times 10^4 g\times (70^oC-10^oC)}[/tex]

[tex]c=0.004167 J/g^oC[/tex]

0.004167 J/g°C is the specific heat of a substance.

Answer:

D

Explanation:

O

2  is the limiting reagent because the least moles of this are used in the reaction.

Final answer:

Oxygen (O2) is the limiting reactant in the reaction 4NH3 + 5O2 = 4NO + 6H2O when 4 grams of O2 and 2 grams of NH3 are used, as it has a smaller ratio of moles to its coefficient in the balanced equation compared to NH3. So the correct option is D.

Explanation:

The limiting reactant in the chemical reaction 4NH3 + 5O2 = 4NO + 6H2O can be determined by calculating the moles of the reactants and comparing their mole ratio with the stoichiometry of the balanced equation. First, calculate the moles of NH3 and O2 using their molar masses (NH3: 17 g/mol, O2: 32 g/mol):

Next, divide the moles of each reactant by their respective coefficients in the balanced equation:

Since the ratio for NH3 is larger than the ratio for O2, O2 is the limiting reactant. This means that not all of the NH3 will be used up in the reaction.